Expansions: new ${authresults {mch}} for an Authentication-Results header
[exim.git] / src / src / smtp_in.c
CommitLineData
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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
8d67ada3
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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
134static auth_instance *authenticated_by;
135static BOOL auth_advertised;
136#ifdef SUPPORT_TLS
137static BOOL tls_advertised;
138#endif
6c1c3d1d 139static BOOL dsn_advertised;
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140static BOOL esmtp;
141static BOOL helo_required = FALSE;
142static BOOL helo_verify = FALSE;
143static BOOL helo_seen;
144static BOOL helo_accept_junk;
145static BOOL count_nonmail;
146static BOOL pipelining_advertised;
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147static BOOL rcpt_smtp_response_same;
148static BOOL rcpt_in_progress;
059ec3d9 149static int nonmail_command_count;
8f128379 150static BOOL smtp_exit_function_called = 0;
8c5d388a 151#ifdef SUPPORT_I18N
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152static BOOL smtputf8_advertised;
153#endif
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154static int synprot_error_count;
155static int unknown_command_count;
156static int sync_cmd_limit;
157static int smtp_write_error = 0;
158
2679d413 159static uschar *rcpt_smtp_response;
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160static uschar *smtp_data_buffer;
161static uschar *smtp_cmd_data;
162
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163/* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
164final fields of all except AUTH are forced TRUE at the start of a new message
165setup, to allow one of each between messages that is not counted as a nonmail
166command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
167allow a new EHLO after starting up TLS.
168
169AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
170counted. However, the flag is changed when AUTH is received, so that multiple
171failing AUTHs will eventually hit the limit. After a successful AUTH, another
172AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
173forced TRUE, to allow for the re-authentication that can happen at that point.
174
175QUIT is also "falsely" labelled as a mail command so that it doesn't up the
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176count of non-mail commands and possibly provoke an error.
177
178tls_auth is a pseudo-command, never expected in input. It is activated
179on TLS startup and looks for a tls authenticator. */
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180
181static smtp_cmd_list cmd_list[] = {
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182 /* name len cmd has_arg is_mail_cmd */
183
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184 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
185 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
186 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
187 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
188 #ifdef SUPPORT_TLS
189 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
69d8eed7 190 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, FALSE },
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191 #endif
192
193/* If you change anything above here, also fix the definitions below. */
194
195 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
196 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
197 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
18481de3 198 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
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199 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
200 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
201 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
202 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
203 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
204 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
205};
206
207static smtp_cmd_list *cmd_list_end =
208 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
209
210#define CMD_LIST_RSET 0
211#define CMD_LIST_HELO 1
212#define CMD_LIST_EHLO 2
213#define CMD_LIST_AUTH 3
214#define CMD_LIST_STARTTLS 4
b3ef41c9 215#define CMD_LIST_TLS_AUTH 5
059ec3d9 216
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217/* This list of names is used for performing the smtp_no_mail logging action.
218It must be kept in step with the SCH_xxx enumerations. */
219
220static uschar *smtp_names[] =
221 {
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222 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
223 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
224 US"STARTTLS", US"VRFY" };
b4ed4da0 225
e524074d 226static uschar *protocols_local[] = {
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227 US"local-smtp", /* HELO */
228 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
229 US"local-esmtp", /* EHLO */
230 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
231 US"local-esmtpa", /* EHLO->AUTH */
232 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
059ec3d9 233 };
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234static uschar *protocols[] = {
235 US"smtp", /* HELO */
236 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
237 US"esmtp", /* EHLO */
238 US"esmtps", /* EHLO->STARTTLS->EHLO */
239 US"esmtpa", /* EHLO->AUTH */
240 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
241 };
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242
243#define pnormal 0
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244#define pextend 2
245#define pcrpted 1 /* added to pextend or pnormal */
246#define pauthed 2 /* added to pextend */
059ec3d9 247
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248/* Sanity check and validate optional args to MAIL FROM: envelope */
249enum {
2ef7ed08 250 ENV_MAIL_OPT_NULL,
d27f98fe 251 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
8ccd00b1 252#ifndef DISABLE_PRDR
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253 ENV_MAIL_OPT_PRDR,
254#endif
6c1c3d1d 255 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
8c5d388a 256#ifdef SUPPORT_I18N
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257 ENV_MAIL_OPT_UTF8,
258#endif
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259 };
260typedef struct {
261 uschar * name; /* option requested during MAIL cmd */
262 int value; /* enum type */
263 BOOL need_value; /* TRUE requires value (name=value pair format)
264 FALSE is a singleton */
265 } env_mail_type_t;
266static env_mail_type_t env_mail_type_list[] = {
267 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
268 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
269 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
8ccd00b1 270#ifndef DISABLE_PRDR
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271 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
272#endif
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273 { US"RET", ENV_MAIL_OPT_RET, TRUE },
274 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
8c5d388a 275#ifdef SUPPORT_I18N
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276 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
277#endif
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278 /* keep this the last entry */
279 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
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280 };
281
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282/* When reading SMTP from a remote host, we have to use our own versions of the
283C input-reading functions, in order to be able to flush the SMTP output only
284when about to read more data from the socket. This is the only way to get
285optimal performance when the client is using pipelining. Flushing for every
286command causes a separate packet and reply packet each time; saving all the
287responses up (when pipelining) combines them into one packet and one response.
288
289For simplicity, these functions are used for *all* SMTP input, not only when
290receiving over a socket. However, after setting up a secure socket (SSL), input
291is read via the OpenSSL library, and another set of functions is used instead
292(see tls.c).
293
294These functions are set in the receive_getc etc. variables and called with the
295same interface as the C functions. However, since there can only ever be
296one incoming SMTP call, we just use a single buffer and flags. There is no need
297to implement a complicated private FILE-like structure.*/
298
299static uschar *smtp_inbuffer;
300static uschar *smtp_inptr;
301static uschar *smtp_inend;
302static int smtp_had_eof;
303static int smtp_had_error;
304
305
7e3ce68e 306/* forward declarations */
bd8fbe36 307static int smtp_read_command(BOOL check_sync, unsigned buffer_lim);
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308static int synprot_error(int type, int code, uschar *data, uschar *errmess);
309static void smtp_quit_handler(uschar **, uschar **);
310static void smtp_rset_handler(void);
311
059ec3d9 312/*************************************************
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313* Recheck synchronization *
314*************************************************/
315
316/* Synchronization checks can never be perfect because a packet may be on its
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317way but not arrived when the check is done. Normally, the checks happen when
318commands are read: Exim ensures that there is no more input in the input buffer.
319In normal cases, the response to the command will be fast, and there is no
320further check.
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321
322However, for some commands an ACL is run, and that can include delays. In those
323cases, it is useful to do another check on the input just before sending the
324response. This also applies at the start of a connection. This function does
325that check by means of the select() function, as long as the facility is not
326disabled or inappropriate. A failure of select() is ignored.
327
328When there is unwanted input, we read it so that it appears in the log of the
329error.
330
331Arguments: none
332Returns: TRUE if all is well; FALSE if there is input pending
333*/
334
335static BOOL
925ac8e4 336wouldblock_reading(void)
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337{
338int fd, rc;
339fd_set fds;
340struct timeval tzero;
341
9067f574 342#ifdef SUPPORT_TLS
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343if (tls_in.active >= 0)
344 return !tls_could_read();
9067f574 345#endif
f4630439 346
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347if (smtp_inptr < smtp_inend)
348 return FALSE;
349
f4630439
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350fd = fileno(smtp_in);
351FD_ZERO(&fds);
352FD_SET(fd, &fds);
353tzero.tv_sec = 0;
354tzero.tv_usec = 0;
355rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
356
357if (rc <= 0) return TRUE; /* Not ready to read */
bd8fbe36 358rc = smtp_getc(GETC_BUFFER_UNLIMITED);
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359if (rc < 0) return TRUE; /* End of file or error */
360
361smtp_ungetc(rc);
362rc = smtp_inend - smtp_inptr;
363if (rc > 150) rc = 150;
364smtp_inptr[rc] = 0;
365return FALSE;
366}
367
925ac8e4
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368static BOOL
369check_sync(void)
370{
371if (!smtp_enforce_sync || sender_host_address == NULL || sender_host_notsocket)
372 return TRUE;
373
374return wouldblock_reading();
375}
376
377
378/* If there's input waiting (and we're doing pipelineing) then we can pipeline
379a reponse with the one following. */
380
381static BOOL
382pipeline_response(void)
383{
384if ( !smtp_enforce_sync || !sender_host_address
385 || sender_host_notsocket || !pipelining_advertised)
386 return FALSE;
387
388return !wouldblock_reading();
389}
390
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391
392
393/*************************************************
394* Log incomplete transactions *
395*************************************************/
396
397/* This function is called after a transaction has been aborted by RSET, QUIT,
398connection drops or other errors. It logs the envelope information received
399so far in order to preserve address verification attempts.
400
401Argument: string to indicate what aborted the transaction
402Returns: nothing
403*/
404
405static void
406incomplete_transaction_log(uschar *what)
407{
408if (sender_address == NULL || /* No transaction in progress */
409 !LOGGING(smtp_incomplete_transaction))
410 return;
411
412/* Build list of recipients for logging */
413
414if (recipients_count > 0)
415 {
416 int i;
417 raw_recipients = store_get(recipients_count * sizeof(uschar *));
418 for (i = 0; i < recipients_count; i++)
419 raw_recipients[i] = recipients_list[i].address;
420 raw_recipients_count = recipients_count;
421 }
422
423log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
424 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
425}
426
427
428
429
0d81dabc
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430/* Refill the buffer, and notify DKIM verification code.
431Return false for error or EOF.
432*/
433
434static BOOL
435smtp_refill(unsigned lim)
436{
437int rc, save_errno;
438if (!smtp_out) return FALSE;
439fflush(smtp_out);
440if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
441
442/* Limit amount read, so non-message data is not fed to DKIM */
443
444rc = read(fileno(smtp_in), smtp_inbuffer, MIN(IN_BUFFER_SIZE, lim));
445save_errno = errno;
446alarm(0);
447if (rc <= 0)
448 {
449 /* Must put the error text in fixed store, because this might be during
450 header reading, where it releases unused store above the header. */
451 if (rc < 0)
452 {
453 smtp_had_error = save_errno;
454 smtp_read_error = string_copy_malloc(
455 string_sprintf(" (error: %s)", strerror(save_errno)));
456 }
457 else smtp_had_eof = 1;
458 return FALSE;
459 }
460#ifndef DISABLE_DKIM
461dkim_exim_verify_feed(smtp_inbuffer, rc);
462#endif
463smtp_inend = smtp_inbuffer + rc;
464smtp_inptr = smtp_inbuffer;
465return TRUE;
466}
467
f4630439 468/*************************************************
059ec3d9
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469* SMTP version of getc() *
470*************************************************/
471
472/* This gets the next byte from the SMTP input buffer. If the buffer is empty,
473it flushes the output, and refills the buffer, with a timeout. The signal
474handler is set appropriately by the calling function. This function is not used
4c04137d 475after a connection has negotiated itself into an TLS/SSL state.
059ec3d9 476
bd8fbe36 477Arguments: lim Maximum amount to read/buffer
059ec3d9
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478Returns: the next character or EOF
479*/
480
481int
bd8fbe36 482smtp_getc(unsigned lim)
059ec3d9
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483{
484if (smtp_inptr >= smtp_inend)
0d81dabc 485 if (!smtp_refill(lim))
059ec3d9 486 return EOF;
059ec3d9
PH
487return *smtp_inptr++;
488}
489
0d81dabc
JH
490uschar *
491smtp_getbuf(unsigned * len)
492{
493unsigned size;
494uschar * buf;
495
496if (smtp_inptr >= smtp_inend)
497 if (!smtp_refill(*len))
498 { *len = 0; return NULL; }
499
500if ((size = smtp_inend - smtp_inptr) > *len) size = *len;
501buf = smtp_inptr;
502smtp_inptr += size;
503*len = size;
504return buf;
505}
506
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507void
508smtp_get_cache(void)
509{
9960d1e5 510#ifndef DISABLE_DKIM
584e96c6
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511int n = smtp_inend - smtp_inptr;
512if (n > 0)
513 dkim_exim_verify_feed(smtp_inptr, n);
584e96c6 514#endif
9960d1e5 515}
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516
517
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518/* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
519previous BDAT chunk and getting new ones when we run out. Uses the
520underlying smtp_getc or tls_getc both for that and for getting the
521(buffered) data byte. EOD signals (an expected) no further data.
522ERR signals a protocol error, and EOF a closed input stream.
523
524Called from read_bdat_smtp() in receive.c for the message body, but also
525by the headers read loop in receive_msg(); manipulates chunking_state
526to handle the BDAT command/response.
527Placed here due to the correlation with the above smtp_getc(), which it wraps,
528and also by the need to do smtp command/response handling.
529
bd8fbe36 530Arguments: lim (ignored)
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531Returns: the next character or ERR, EOD or EOF
532*/
533
534int
bd8fbe36 535bdat_getc(unsigned lim)
7e3ce68e
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536{
537uschar * user_msg = NULL;
538uschar * log_msg;
539
540for(;;)
541 {
79de4f37
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542#ifndef DISABLE_DKIM
543 BOOL dkim_save;
544#endif
545
bd8fbe36
JH
546 if (chunking_data_left > 0)
547 return lwr_receive_getc(chunking_data_left--);
7e3ce68e
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548
549 receive_getc = lwr_receive_getc;
0d81dabc 550 receive_getbuf = lwr_receive_getbuf;
7e3ce68e 551 receive_ungetc = lwr_receive_ungetc;
bd8fbe36 552#ifndef DISABLE_DKIM
79de4f37 553 dkim_save = dkim_collect_input;
bd8fbe36
JH
554 dkim_collect_input = FALSE;
555#endif
7e3ce68e 556
f4630439
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557 /* Unless PIPELINING was offered, there should be no next command
558 until after we ack that chunk */
559
560 if (!pipelining_advertised && !check_sync())
561 {
40525d07
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562 unsigned n = smtp_inend - smtp_inptr;
563 if (n > 32) n = 32;
564
f4630439
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565 incomplete_transaction_log(US"sync failure");
566 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol synchronization error "
567 "(next input sent too soon: pipelining was not advertised): "
9e0ed81f 568 "rejected \"%s\" %s next input=\"%s\"%s",
f4630439 569 smtp_cmd_buffer, host_and_ident(TRUE),
9e0ed81f
JH
570 string_printing(string_copyn(smtp_inptr, n)),
571 smtp_inend - smtp_inptr > n ? "..." : "");
572 (void) synprot_error(L_smtp_protocol_error, 554, NULL,
573 US"SMTP synchronization error");
f4630439
JH
574 goto repeat_until_rset;
575 }
576
7e3ce68e
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577 /* If not the last, ack the received chunk. The last response is delayed
578 until after the data ACL decides on it */
7e3ce68e
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579
580 if (chunking_state == CHUNKING_LAST)
584e96c6
JH
581 {
582#ifndef DISABLE_DKIM
e983e85a 583 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
584e96c6 584#endif
7e3ce68e 585 return EOD;
584e96c6 586 }
7e3ce68e 587
925ac8e4 588 smtp_printf("250 %u byte chunk received\r\n", FALSE, chunking_datasize);
bd8fbe36
JH
589 chunking_state = CHUNKING_OFFERED;
590 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
7e3ce68e
JH
591
592 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
593 QUIT, RSET or NOOP but handling them seems obvious */
594
595next_cmd:
bd8fbe36 596 switch(smtp_read_command(TRUE, 1))
7e3ce68e
JH
597 {
598 default:
599 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
600 US"only BDAT permissible after non-LAST BDAT");
601
602 repeat_until_rset:
bd8fbe36 603 switch(smtp_read_command(TRUE, 1))
7e3ce68e
JH
604 {
605 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
606 case EOF_CMD: return EOF;
607 case RSET_CMD: smtp_rset_handler(); return ERR;
608 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
609 US"only RSET accepted now") > 0)
610 return EOF;
611 goto repeat_until_rset;
612 }
613
614 case QUIT_CMD:
615 smtp_quit_handler(&user_msg, &log_msg);
616 /*FALLTHROUGH*/
617 case EOF_CMD:
618 return EOF;
619
620 case RSET_CMD:
621 smtp_rset_handler();
622 return ERR;
623
624 case NOOP_CMD:
625 HAD(SCH_NOOP);
925ac8e4 626 smtp_printf("250 OK\r\n", FALSE);
7e3ce68e
JH
627 goto next_cmd;
628
629 case BDAT_CMD:
630 {
631 int n;
632
633 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
634 {
635 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
636 US"missing size for BDAT command");
637 return ERR;
638 }
639 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
640 ? CHUNKING_LAST : CHUNKING_ACTIVE;
641 chunking_data_left = chunking_datasize;
bd8fbe36
JH
642 DEBUG(D_receive) debug_printf("chunking state %d, %d bytes\n",
643 (int)chunking_state, chunking_data_left);
7e3ce68e
JH
644
645 if (chunking_datasize == 0)
646 if (chunking_state == CHUNKING_LAST)
647 return EOD;
648 else
649 {
650 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
651 US"zero size for BDAT command");
652 goto repeat_until_rset;
653 }
654
655 receive_getc = bdat_getc;
0d81dabc 656 receive_getbuf = bdat_getbuf;
7e3ce68e 657 receive_ungetc = bdat_ungetc;
bd8fbe36 658#ifndef DISABLE_DKIM
79de4f37 659 dkim_collect_input = dkim_save;
bd8fbe36 660#endif
7e3ce68e
JH
661 break; /* to top of main loop */
662 }
663 }
664 }
665}
666
0d81dabc
JH
667uschar *
668bdat_getbuf(unsigned * len)
669{
670uschar * buf;
671
672if (chunking_data_left <= 0)
673 { *len = 0; return NULL; }
674
675if (*len > chunking_data_left) *len = chunking_data_left;
676buf = lwr_receive_getbuf(len); /* Either smtp_getbuf or tls_getbuf */
677chunking_data_left -= *len;
678return buf;
679}
680
1ebe15c3 681void
45bd315d
JH
682bdat_flush_data(void)
683{
e99a3a6c 684while (chunking_data_left)
db57e575 685 {
e99a3a6c
JH
686 unsigned n = chunking_data_left;
687 (void) bdat_getbuf(&n);
db57e575 688 }
45bd315d
JH
689
690receive_getc = lwr_receive_getc;
0d81dabc 691receive_getbuf = lwr_receive_getbuf;
45bd315d
JH
692receive_ungetc = lwr_receive_ungetc;
693
694if (chunking_state != CHUNKING_LAST)
bd8fbe36 695 {
45bd315d 696 chunking_state = CHUNKING_OFFERED;
bd8fbe36
JH
697 DEBUG(D_receive) debug_printf("chunking state %d\n", (int)chunking_state);
698 }
45bd315d
JH
699}
700
7e3ce68e
JH
701
702
703
059ec3d9
PH
704/*************************************************
705* SMTP version of ungetc() *
706*************************************************/
707
708/* Puts a character back in the input buffer. Only ever
709called once.
710
711Arguments:
712 ch the character
713
714Returns: the character
715*/
716
717int
718smtp_ungetc(int ch)
719{
7e3ce68e 720*--smtp_inptr = ch;
059ec3d9
PH
721return ch;
722}
723
724
7e3ce68e
JH
725int
726bdat_ungetc(int ch)
727{
728chunking_data_left++;
729return lwr_receive_ungetc(ch);
730}
731
059ec3d9
PH
732
733
734/*************************************************
735* SMTP version of feof() *
736*************************************************/
737
738/* Tests for a previous EOF
739
740Arguments: none
741Returns: non-zero if the eof flag is set
742*/
743
744int
745smtp_feof(void)
746{
747return smtp_had_eof;
748}
749
750
751
752
753/*************************************************
754* SMTP version of ferror() *
755*************************************************/
756
757/* Tests for a previous read error, and returns with errno
758restored to what it was when the error was detected.
759
760Arguments: none
761Returns: non-zero if the error flag is set
762*/
763
764int
765smtp_ferror(void)
766{
767errno = smtp_had_error;
768return smtp_had_error;
769}
770
771
772
58eb016e
PH
773/*************************************************
774* Test for characters in the SMTP buffer *
775*************************************************/
776
777/* Used at the end of a message
778
779Arguments: none
780Returns: TRUE/FALSE
781*/
782
783BOOL
784smtp_buffered(void)
785{
786return smtp_inptr < smtp_inend;
787}
788
789
059ec3d9
PH
790
791/*************************************************
792* Write formatted string to SMTP channel *
793*************************************************/
794
795/* This is a separate function so that we don't have to repeat everything for
796TLS support or debugging. It is global so that the daemon and the
797authentication functions can use it. It does not return any error indication,
798because major problems such as dropped connections won't show up till an output
799flush for non-TLS connections. The smtp_fflush() function is available for
800checking that: for convenience, TLS output errors are remembered here so that
801they are also picked up later by smtp_fflush().
802
803Arguments:
804 format format string
925ac8e4 805 more further data expected
059ec3d9
PH
806 ... optional arguments
807
808Returns: nothing
809*/
810
811void
925ac8e4 812smtp_printf(const char *format, BOOL more, ...)
059ec3d9
PH
813{
814va_list ap;
815
925ac8e4
JH
816va_start(ap, more);
817smtp_vprintf(format, more, ap);
ce552449
NM
818va_end(ap);
819}
820
821/* This is split off so that verify.c:respond_printf() can, in effect, call
822smtp_printf(), bearing in mind that in C a vararg function can't directly
fb08281f 823call another vararg function, only a function which accepts a va_list. */
ce552449
NM
824
825void
925ac8e4 826smtp_vprintf(const char *format, BOOL more, va_list ap)
ce552449 827{
fb08281f
DW
828BOOL yield;
829
830yield = string_vformat(big_buffer, big_buffer_size, format, ap);
ce552449 831
059ec3d9
PH
832DEBUG(D_receive)
833 {
fb08281f
DW
834 void *reset_point = store_get(0);
835 uschar *msg_copy, *cr, *end;
836 msg_copy = string_copy(big_buffer);
837 end = msg_copy + Ustrlen(msg_copy);
838 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
839 memmove(cr, cr + 1, (end--) - cr);
840 debug_printf("SMTP>> %s", msg_copy);
841 store_reset(reset_point);
059ec3d9
PH
842 }
843
fb08281f 844if (!yield)
2679d413
PH
845 {
846 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
847 smtp_closedown(US"Unexpected error");
9bfb7e1b 848 exim_exit(EXIT_FAILURE, NULL);
2679d413 849 }
2679d413
PH
850
851/* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
852have had the same. Note: this code is also present in smtp_respond(). It would
853be tidier to have it only in one place, but when it was added, it was easier to
854do it that way, so as not to have to mess with the code for the RCPT command,
855which sometimes uses smtp_printf() and sometimes smtp_respond(). */
856
857if (rcpt_in_progress)
858 {
859 if (rcpt_smtp_response == NULL)
860 rcpt_smtp_response = string_copy(big_buffer);
861 else if (rcpt_smtp_response_same &&
862 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
863 rcpt_smtp_response_same = FALSE;
864 rcpt_in_progress = FALSE;
865 }
059ec3d9 866
2679d413 867/* Now write the string */
059ec3d9
PH
868
869#ifdef SUPPORT_TLS
817d9f57 870if (tls_in.active >= 0)
059ec3d9 871 {
925ac8e4 872 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer), more) < 0)
817d9f57 873 smtp_write_error = -1;
059ec3d9
PH
874 }
875else
876#endif
877
2679d413 878if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
059ec3d9
PH
879}
880
881
882
883/*************************************************
884* Flush SMTP out and check for error *
885*************************************************/
886
887/* This function isn't currently used within Exim (it detects errors when it
888tries to read the next SMTP input), but is available for use in local_scan().
889For non-TLS connections, it flushes the output and checks for errors. For
890TLS-connections, it checks for a previously-detected TLS write error.
891
892Arguments: none
893Returns: 0 for no error; -1 after an error
894*/
895
896int
897smtp_fflush(void)
898{
817d9f57 899if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
059ec3d9
PH
900return smtp_write_error;
901}
902
903
904
905/*************************************************
906* SMTP command read timeout *
907*************************************************/
908
909/* Signal handler for timing out incoming SMTP commands. This attempts to
910finish off tidily.
911
912Argument: signal number (SIGALRM)
913Returns: nothing
914*/
915
916static void
917command_timeout_handler(int sig)
918{
919sig = sig; /* Keep picky compilers happy */
920log_write(L_lost_incoming_connection,
921 LOG_MAIN, "SMTP command timeout on%s connection from %s",
817d9f57 922 (tls_in.active >= 0)? " TLS" : "",
059ec3d9
PH
923 host_and_ident(FALSE));
924if (smtp_batched_input)
925 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
8f128379
PH
926smtp_notquit_exit(US"command-timeout", US"421",
927 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
9bfb7e1b 928exim_exit(EXIT_FAILURE, US"receiving");
059ec3d9
PH
929}
930
931
932
933/*************************************************
934* SIGTERM received *
935*************************************************/
936
937/* Signal handler for handling SIGTERM. Again, try to finish tidily.
938
939Argument: signal number (SIGTERM)
940Returns: nothing
941*/
942
943static void
944command_sigterm_handler(int sig)
945{
946sig = sig; /* Keep picky compilers happy */
947log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
948if (smtp_batched_input)
949 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
8f128379
PH
950smtp_notquit_exit(US"signal-exit", US"421",
951 US"%s: Service not available - closing connection", smtp_active_hostname);
9bfb7e1b 952exim_exit(EXIT_FAILURE, US"receiving");
059ec3d9
PH
953}
954
955
956
a14e5636 957
cee5f132 958#ifdef SUPPORT_PROXY
a3c86431 959/*************************************************
a3bddaa8
TL
960* Restore socket timeout to previous value *
961*************************************************/
962/* If the previous value was successfully retrieved, restore
963it before returning control to the non-proxy routines
964
965Arguments: fd - File descriptor for input
966 get_ok - Successfully retrieved previous values
967 tvtmp - Time struct with previous values
968 vslen - Length of time struct
969Returns: none
970*/
971static void
f267271d 972restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
a3bddaa8
TL
973{
974if (get_ok == 0)
f267271d 975 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
a3bddaa8
TL
976}
977
978/*************************************************
a3c86431
TL
979* Check if host is required proxy host *
980*************************************************/
981/* The function determines if inbound host will be a regular smtp host
1811cb4c
JH
982or if it is configured that it must use Proxy Protocol. A local
983connection cannot.
a3c86431
TL
984
985Arguments: none
986Returns: bool
987*/
988
989static BOOL
990check_proxy_protocol_host()
991{
992int rc;
a3c86431 993
1811cb4c
JH
994if ( sender_host_address
995 && (rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
996 sender_host_address, NULL)) == OK)
a3c86431
TL
997 {
998 DEBUG(D_receive)
999 debug_printf("Detected proxy protocol configured host\n");
1000 proxy_session = TRUE;
1001 }
1002return proxy_session;
1003}
1004
1005
1006/*************************************************
3f251b3c
PP
1007* Read data until newline or end of buffer *
1008*************************************************/
1009/* While SMTP is server-speaks-first, TLS is client-speaks-first, so we can't
1010read an entire buffer and assume there will be nothing past a proxy protocol
1011header. Our approach normally is to use stdio, but again that relies upon
1012"STARTTLS\r\n" and a server response before the client starts TLS handshake, or
1013reading _nothing_ before client TLS handshake. So we don't want to use the
1014usual buffering reads which may read enough to block TLS starting.
1015
1016So unfortunately we're down to "read one byte at a time, with a syscall each,
1017and expect a little overhead", for all proxy-opened connections which are v1,
1018just to handle the TLS-on-connect case. Since SSL functions wrap the
1019underlying fd, we can't assume that we can feed them any already-read content.
1020
1021We need to know where to read to, the max capacity, and we'll read until we
1022get a CR and one more character. Let the caller scream if it's CR+!LF.
1023
1024Return the amount read.
1025*/
1026
1027static int
da88acae 1028swallow_until_crlf(int fd, uschar *base, int already, int capacity)
3f251b3c 1029{
2c0f3ea1
JH
1030uschar *to = base + already;
1031uschar *cr;
1032int have = 0;
1033int ret;
1034int last = 0;
1035
1036/* For "PROXY UNKNOWN\r\n" we, at time of writing, expect to have read
1037up through the \r; for the _normal_ case, we haven't yet seen the \r. */
da88acae 1038
2c0f3ea1
JH
1039cr = memchr(base, '\r', already);
1040if (cr != NULL)
1041 {
1042 if ((cr - base) < already - 1)
da88acae 1043 {
2c0f3ea1
JH
1044 /* \r and presumed \n already within what we have; probably not
1045 actually proxy protocol, but abort cleanly. */
1046 return 0;
da88acae 1047 }
2c0f3ea1
JH
1048 /* \r is last character read, just need one more. */
1049 last = 1;
1050 }
1051
1052while (capacity > 0)
1053 {
1054 do { ret = recv(fd, to, 1, 0); } while (ret == -1 && errno == EINTR);
1055 if (ret == -1)
1056 return -1;
1057 have++;
1058 if (last)
1059 return have;
1060 if (*to == '\r')
1061 last = 1;
1062 capacity--;
1063 to++;
1064 }
1065
1066/* reached end without having room for a final newline, abort */
1067errno = EOVERFLOW;
1068return -1;
3f251b3c
PP
1069}
1070
1071/*************************************************
a3c86431
TL
1072* Setup host for proxy protocol *
1073*************************************************/
1074/* The function configures the connection based on a header from the
1075inbound host to use Proxy Protocol. The specification is very exact
1076so exit with an error if do not find the exact required pieces. This
1077includes an incorrect number of spaces separating args.
1078
1079Arguments: none
f267271d 1080Returns: Boolean success
a3c86431
TL
1081*/
1082
1811cb4c 1083static void
a3c86431
TL
1084setup_proxy_protocol_host()
1085{
1086union {
1087 struct {
1088 uschar line[108];
1089 } v1;
1090 struct {
1091 uschar sig[12];
36719342
TL
1092 uint8_t ver_cmd;
1093 uint8_t fam;
1094 uint16_t len;
a3c86431
TL
1095 union {
1096 struct { /* TCP/UDP over IPv4, len = 12 */
1097 uint32_t src_addr;
1098 uint32_t dst_addr;
1099 uint16_t src_port;
1100 uint16_t dst_port;
1101 } ip4;
1102 struct { /* TCP/UDP over IPv6, len = 36 */
1103 uint8_t src_addr[16];
1104 uint8_t dst_addr[16];
1105 uint16_t src_port;
1106 uint16_t dst_port;
1107 } ip6;
1108 struct { /* AF_UNIX sockets, len = 216 */
1109 uschar src_addr[108];
1110 uschar dst_addr[108];
1111 } unx;
1112 } addr;
1113 } v2;
1114} hdr;
1115
eb57651e
TL
1116/* Temp variables used in PPv2 address:port parsing */
1117uint16_t tmpport;
1118char tmpip[INET_ADDRSTRLEN];
1119struct sockaddr_in tmpaddr;
1120char tmpip6[INET6_ADDRSTRLEN];
1121struct sockaddr_in6 tmpaddr6;
1122
da88acae
PP
1123/* We can't read "all data until end" because while SMTP is
1124server-speaks-first, the TLS handshake is client-speaks-first, so for
1125TLS-on-connect ports the proxy protocol header will usually be immediately
1126followed by a TLS handshake, and with N TLS libraries, we can't reliably
1127reinject data for reading by those. So instead we first read "enough to be
1128safely read within the header, and figure out how much more to read".
1129For v1 we will later read to the end-of-line, for v2 we will read based upon
1130the stated length.
1131
1132The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
1133data is needed total. For v1, where the line looks like:
1134PROXY TCPn L3src L3dest SrcPort DestPort \r\n
1135
1136However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
1137We seem to support that. So, if we read 14 octets then we can tell if we're
1138v2 or v1. If we're v1, we can continue reading as normal.
1139
1140If we're v2, we can't slurp up the entire header. We need the length in the
114115th & 16th octets, then to read everything after that.
1142
1143So to safely handle v1 and v2, with client-sent-first supported correctly,
1144we have to do a minimum of 3 read calls, not 1. Eww.
1145*/
1146
1147#define PROXY_INITIAL_READ 14
1148#define PROXY_V2_HEADER_SIZE 16
1149#if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
1150# error Code bug in sizes of data to read for proxy usage
1151#endif
1152
eb57651e 1153int get_ok = 0;
f267271d
JH
1154int size, ret;
1155int fd = fileno(smtp_in);
36719342 1156const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
9e7e0f6a 1157uschar * iptype; /* To display debug info */
a3c86431 1158struct timeval tv;
a3bddaa8 1159struct timeval tvtmp;
f267271d 1160socklen_t vslen = sizeof(struct timeval);
1811cb4c 1161BOOL yield = FALSE;
a3c86431 1162
a3bddaa8 1163/* Save current socket timeout values */
f267271d 1164get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
a3bddaa8 1165
a3c86431
TL
1166/* Proxy Protocol host must send header within a short time
1167(default 3 seconds) or it's considered invalid */
1168tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
1169tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
f267271d 1170if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
1811cb4c 1171 goto bad;
a3bddaa8 1172
a3c86431
TL
1173do
1174 {
eb57651e 1175 /* The inbound host was declared to be a Proxy Protocol host, so
2c0f3ea1
JH
1176 don't do a PEEK into the data, actually slurp up enough to be
1177 "safe". Can't take it all because TLS-on-connect clients follow
1178 immediately with TLS handshake. */
3f251b3c 1179 ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
a3c86431
TL
1180 }
1181 while (ret == -1 && errno == EINTR);
1182
1183if (ret == -1)
f267271d 1184 goto proxyfail;
a3c86431 1185
da88acae
PP
1186/* For v2, handle reading the length, and then the rest. */
1187if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
a3c86431 1188 {
da88acae
PP
1189 int retmore;
1190 uint8_t ver;
1191
1192 /* First get the length fields. */
1193 do
1194 {
1195 retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
1196 } while (retmore == -1 && errno == EINTR);
1197 if (retmore == -1)
3f251b3c 1198 goto proxyfail;
da88acae 1199 ret += retmore;
3f251b3c
PP
1200
1201 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
36719342
TL
1202
1203 /* May 2014: haproxy combined the version and command into one byte to
2c0f3ea1
JH
1204 allow two full bytes for the length field in order to proxy SSL
1205 connections. SSL Proxy is not supported in this version of Exim, but
1206 must still separate values here. */
36719342
TL
1207
1208 if (ver != 0x02)
1209 {
1210 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
1211 goto proxyfail;
1212 }
da88acae 1213
36719342 1214 /* The v2 header will always be 16 bytes per the spec. */
5d036699 1215 size = 16 + ntohs(hdr.v2.len);
da88acae
PP
1216 DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
1217 size, (int)sizeof(hdr));
1218
1219 /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
1220 amount that we need. Double-check that the size is not unreasonable, then
1221 get the rest. */
1222 if (size > sizeof(hdr))
a3c86431 1223 {
da88acae 1224 DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
a3c86431
TL
1225 goto proxyfail;
1226 }
da88acae
PP
1227
1228 do
1229 {
1230 do
1231 {
1232 retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
1233 } while (retmore == -1 && errno == EINTR);
1234 if (retmore == -1)
1235 goto proxyfail;
1236 ret += retmore;
1237 DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
1238 } while (ret < size);
1239
1240 } /* end scope for getting rest of data for v2 */
1241
1242/* At this point: if PROXYv2, we've read the exact size required for all data;
1243if PROXYv1 then we've read "less than required for any valid line" and should
1244read the rest". */
1245
1246if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
1247 {
1248 uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
1249
36719342 1250 switch (cmd)
a3c86431
TL
1251 {
1252 case 0x01: /* PROXY command */
1253 switch (hdr.v2.fam)
1254 {
eb57651e
TL
1255 case 0x11: /* TCPv4 address type */
1256 iptype = US"IPv4";
1257 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
5d036699
JH
1258 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1259 if (!string_is_ip_address(US tmpip, NULL))
eb57651e
TL
1260 {
1261 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
f267271d 1262 goto proxyfail;
eb57651e 1263 }
e6d2a989 1264 proxy_local_address = sender_host_address;
eb57651e
TL
1265 sender_host_address = string_copy(US tmpip);
1266 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
e6d2a989 1267 proxy_local_port = sender_host_port;
eb57651e
TL
1268 sender_host_port = tmpport;
1269 /* Save dest ip/port */
1270 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
5d036699
JH
1271 inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
1272 if (!string_is_ip_address(US tmpip, NULL))
eb57651e
TL
1273 {
1274 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
f267271d 1275 goto proxyfail;
eb57651e 1276 }
7a2fa0bc 1277 proxy_external_address = string_copy(US tmpip);
eb57651e 1278 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
7a2fa0bc 1279 proxy_external_port = tmpport;
a3c86431 1280 goto done;
eb57651e
TL
1281 case 0x21: /* TCPv6 address type */
1282 iptype = US"IPv6";
1283 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
5d036699
JH
1284 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1285 if (!string_is_ip_address(US tmpip6, NULL))
eb57651e
TL
1286 {
1287 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
f267271d 1288 goto proxyfail;
eb57651e 1289 }
e6d2a989 1290 proxy_local_address = sender_host_address;
eb57651e
TL
1291 sender_host_address = string_copy(US tmpip6);
1292 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
e6d2a989 1293 proxy_local_port = sender_host_port;
eb57651e
TL
1294 sender_host_port = tmpport;
1295 /* Save dest ip/port */
1296 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
5d036699
JH
1297 inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
1298 if (!string_is_ip_address(US tmpip6, NULL))
eb57651e
TL
1299 {
1300 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
f267271d 1301 goto proxyfail;
eb57651e 1302 }
7a2fa0bc 1303 proxy_external_address = string_copy(US tmpip6);
eb57651e 1304 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
7a2fa0bc 1305 proxy_external_port = tmpport;
a3c86431 1306 goto done;
eb57651e
TL
1307 default:
1308 DEBUG(D_receive)
1309 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
1310 hdr.v2.fam);
1311 goto proxyfail;
a3c86431
TL
1312 }
1313 /* Unsupported protocol, keep local connection address */
1314 break;
1315 case 0x00: /* LOCAL command */
1316 /* Keep local connection address for LOCAL */
9e7e0f6a 1317 iptype = US"local";
a3c86431
TL
1318 break;
1319 default:
eb57651e 1320 DEBUG(D_receive)
36719342 1321 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
a3c86431
TL
1322 goto proxyfail;
1323 }
1324 }
5d036699 1325else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
a3c86431 1326 {
3f251b3c
PP
1327 uschar *p;
1328 uschar *end;
a3c86431
TL
1329 uschar *sp; /* Utility variables follow */
1330 int tmp_port;
3f251b3c 1331 int r2;
a3c86431
TL
1332 char *endc;
1333
3f251b3c 1334 /* get the rest of the line */
da88acae 1335 r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
3f251b3c
PP
1336 if (r2 == -1)
1337 goto proxyfail;
1338 ret += r2;
1339
1340 p = string_copy(hdr.v1.line);
1341 end = memchr(p, '\r', ret - 1);
1342
da88acae 1343 if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
a3c86431
TL
1344 {
1345 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
1346 goto proxyfail;
1347 }
1348 *end = '\0'; /* Terminate the string */
a5d4db40 1349 size = end + 2 - p; /* Skip header + CRLF */
a3c86431 1350 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
3f251b3c 1351 DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
a3c86431 1352 /* Step through the string looking for the required fields. Ensure
2c0f3ea1 1353 strict adherence to required formatting, exit for any error. */
a3c86431
TL
1354 p += 5;
1355 if (!isspace(*(p++)))
1356 {
1357 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1358 goto proxyfail;
1359 }
1360 if (!Ustrncmp(p, CCS"TCP4", 4))
1361 iptype = US"IPv4";
1362 else if (!Ustrncmp(p,CCS"TCP6", 4))
1363 iptype = US"IPv6";
1364 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1365 {
1366 iptype = US"Unknown";
1367 goto done;
1368 }
1369 else
1370 {
1371 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1372 goto proxyfail;
1373 }
1374
1375 p += Ustrlen(iptype);
1376 if (!isspace(*(p++)))
1377 {
1378 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1379 goto proxyfail;
1380 }
1381 /* Find the end of the arg */
1382 if ((sp = Ustrchr(p, ' ')) == NULL)
1383 {
1384 DEBUG(D_receive)
1385 debug_printf("Did not find proxied src %s\n", iptype);
1386 goto proxyfail;
1387 }
1388 *sp = '\0';
5d036699 1389 if(!string_is_ip_address(p, NULL))
a3c86431
TL
1390 {
1391 DEBUG(D_receive)
1392 debug_printf("Proxied src arg is not an %s address\n", iptype);
1393 goto proxyfail;
1394 }
e6d2a989 1395 proxy_local_address = sender_host_address;
a3c86431
TL
1396 sender_host_address = p;
1397 p = sp + 1;
1398 if ((sp = Ustrchr(p, ' ')) == NULL)
1399 {
1400 DEBUG(D_receive)
1401 debug_printf("Did not find proxy dest %s\n", iptype);
1402 goto proxyfail;
1403 }
1404 *sp = '\0';
5d036699 1405 if(!string_is_ip_address(p, NULL))
a3c86431
TL
1406 {
1407 DEBUG(D_receive)
1408 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1409 goto proxyfail;
1410 }
7a2fa0bc 1411 proxy_external_address = p;
a3c86431
TL
1412 p = sp + 1;
1413 if ((sp = Ustrchr(p, ' ')) == NULL)
1414 {
1415 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1416 goto proxyfail;
1417 }
1418 *sp = '\0';
5d036699 1419 tmp_port = strtol(CCS p, &endc, 10);
a3c86431
TL
1420 if (*endc || tmp_port == 0)
1421 {
1422 DEBUG(D_receive)
1423 debug_printf("Proxied src port '%s' not an integer\n", p);
1424 goto proxyfail;
1425 }
e6d2a989 1426 proxy_local_port = sender_host_port;
a3c86431
TL
1427 sender_host_port = tmp_port;
1428 p = sp + 1;
1429 if ((sp = Ustrchr(p, '\0')) == NULL)
1430 {
1431 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1432 goto proxyfail;
1433 }
5d036699 1434 tmp_port = strtol(CCS p, &endc, 10);
a3c86431
TL
1435 if (*endc || tmp_port == 0)
1436 {
1437 DEBUG(D_receive)
1438 debug_printf("Proxy dest port '%s' not an integer\n", p);
1439 goto proxyfail;
1440 }
7a2fa0bc 1441 proxy_external_port = tmp_port;
a3c86431 1442 /* Already checked for /r /n above. Good V1 header received. */
a3c86431
TL
1443 }
1444else
1445 {
1446 /* Wrong protocol */
eb57651e 1447 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
da88acae 1448 (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
a3c86431
TL
1449 goto proxyfail;
1450 }
1451
1811cb4c
JH
1452done:
1453 DEBUG(D_receive)
1454 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1455 yield = proxy_session;
1456
1457/* Don't flush any potential buffer contents. Any input on proxyfail
1458should cause a synchronization failure */
1459
a3c86431 1460proxyfail:
1811cb4c 1461 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
a3c86431 1462
1811cb4c
JH
1463bad:
1464 if (yield)
1465 {
1466 sender_host_name = NULL;
1467 (void) host_name_lookup();
1468 host_build_sender_fullhost();
1469 }
1470 else
1471 {
1472 proxy_session_failed = TRUE;
1473 DEBUG(D_receive)
1474 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
1475 }
1476
1477return;
a3c86431
TL
1478}
1479#endif
1480
059ec3d9
PH
1481/*************************************************
1482* Read one command line *
1483*************************************************/
1484
1485/* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1486There are sites that don't do this, and in any case internal SMTP probably
1487should check only for LF. Consequently, we check here for LF only. The line
1488ends up with [CR]LF removed from its end. If we get an overlong line, treat as
3ee512ff
PH
1489an unknown command. The command is read into the global smtp_cmd_buffer so that
1490it is available via $smtp_command.
059ec3d9
PH
1491
1492The character reading routine sets up a timeout for each block actually read
1493from the input (which may contain more than one command). We set up a special
1494signal handler that closes down the session on a timeout. Control does not
1495return when it runs.
1496
1497Arguments:
bd8fbe36
JH
1498 check_sync if TRUE, check synchronization rules if global option is TRUE
1499 buffer_lim maximum to buffer in lower layer
059ec3d9
PH
1500
1501Returns: a code identifying the command (enumerated above)
1502*/
1503
1504static int
bd8fbe36 1505smtp_read_command(BOOL check_sync, unsigned buffer_lim)
059ec3d9
PH
1506{
1507int c;
1508int ptr = 0;
1509smtp_cmd_list *p;
1510BOOL hadnull = FALSE;
1511
1512os_non_restarting_signal(SIGALRM, command_timeout_handler);
1513
bd8fbe36 1514while ((c = (receive_getc)(buffer_lim)) != '\n' && c != EOF)
059ec3d9 1515 {
bd8fbe36 1516 if (ptr >= SMTP_CMD_BUFFER_SIZE)
059ec3d9
PH
1517 {
1518 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1519 return OTHER_CMD;
1520 }
1521 if (c == 0)
1522 {
1523 hadnull = TRUE;
1524 c = '?';
1525 }
3ee512ff 1526 smtp_cmd_buffer[ptr++] = c;
059ec3d9
PH
1527 }
1528
1529receive_linecount++; /* For BSMTP errors */
1530os_non_restarting_signal(SIGALRM, sigalrm_handler);
1531
1532/* If hit end of file, return pseudo EOF command. Whether we have a
1533part-line already read doesn't matter, since this is an error state. */
1534
1535if (c == EOF) return EOF_CMD;
1536
1537/* Remove any CR and white space at the end of the line, and terminate the
1538string. */
1539
3ee512ff
PH
1540while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1541smtp_cmd_buffer[ptr] = 0;
059ec3d9 1542
3ee512ff 1543DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
059ec3d9
PH
1544
1545/* NULLs are not allowed in SMTP commands */
1546
1547if (hadnull) return BADCHAR_CMD;
1548
1549/* Scan command list and return identity, having set the data pointer
1550to the start of the actual data characters. Check for SMTP synchronization
1551if required. */
1552
1553for (p = cmd_list; p < cmd_list_end; p++)
1554 {
1811cb4c 1555#ifdef SUPPORT_PROXY
a3c86431 1556 /* Only allow QUIT command if Proxy Protocol parsing failed */
1811cb4c
JH
1557 if (proxy_session && proxy_session_failed && p->cmd != QUIT_CMD)
1558 continue;
1559#endif
2f460950
JH
1560 if ( p->len
1561 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1562 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1563 || smtp_cmd_buffer[p->len] == 0
1564 || smtp_cmd_buffer[p->len] == ' '
1565 ) )
059ec3d9
PH
1566 {
1567 if (smtp_inptr < smtp_inend && /* Outstanding input */
1568 p->cmd < sync_cmd_limit && /* Command should sync */
1569 check_sync && /* Local flag set */
1570 smtp_enforce_sync && /* Global flag set */
1571 sender_host_address != NULL && /* Not local input */
1572 !sender_host_notsocket) /* Really is a socket */
1573 return BADSYN_CMD;
1574
ca86f471
PH
1575 /* The variables $smtp_command and $smtp_command_argument point into the
1576 unmodified input buffer. A copy of the latter is taken for actual
1577 processing, so that it can be chopped up into separate parts if necessary,
1578 for example, when processing a MAIL command options such as SIZE that can
1579 follow the sender address. */
059ec3d9 1580
3ee512ff 1581 smtp_cmd_argument = smtp_cmd_buffer + p->len;
ca86f471
PH
1582 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1583 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1584 smtp_cmd_data = smtp_data_buffer;
059ec3d9
PH
1585
1586 /* Count non-mail commands from those hosts that are controlled in this
1587 way. The default is all hosts. We don't waste effort checking the list
1588 until we get a non-mail command, but then cache the result to save checking
1589 again. If there's a DEFER while checking the host, assume it's in the list.
1590
1591 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1592 start of each incoming message by fiddling with the value in the table. */
1593
1594 if (!p->is_mail_cmd)
1595 {
1596 if (count_nonmail == TRUE_UNSET) count_nonmail =
1597 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1598 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1599 return TOO_MANY_NONMAIL_CMD;
1600 }
1601
ca86f471
PH
1602 /* If there is data for a command that does not expect it, generate the
1603 error here. */
059ec3d9 1604
ca86f471 1605 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
059ec3d9
PH
1606 }
1607 }
1608
cee5f132 1609#ifdef SUPPORT_PROXY
a3c86431
TL
1610/* Only allow QUIT command if Proxy Protocol parsing failed */
1611if (proxy_session && proxy_session_failed)
1612 return PROXY_FAIL_IGNORE_CMD;
1613#endif
1614
059ec3d9
PH
1615/* Enforce synchronization for unknown commands */
1616
1617if (smtp_inptr < smtp_inend && /* Outstanding input */
1618 check_sync && /* Local flag set */
1619 smtp_enforce_sync && /* Global flag set */
1620 sender_host_address != NULL && /* Not local input */
1621 !sender_host_notsocket) /* Really is a socket */
1622 return BADSYN_CMD;
1623
1624return OTHER_CMD;
1625}
1626
1627
1628
1629/*************************************************
1630* Forced closedown of call *
1631*************************************************/
1632
1633/* This function is called from log.c when Exim is dying because of a serious
1634disaster, and also from some other places. If an incoming non-batched SMTP
1635channel is open, it swallows the rest of the incoming message if in the DATA
1636phase, sends the reply string, and gives an error to all subsequent commands
1637except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1638smtp_in.
1639
8f128379
PH
1640Arguments:
1641 message SMTP reply string to send, excluding the code
1642
059ec3d9
PH
1643Returns: nothing
1644*/
1645
1646void
1647smtp_closedown(uschar *message)
1648{
db57e575 1649if (!smtp_in || smtp_batched_input) return;
059ec3d9 1650receive_swallow_smtp();
925ac8e4 1651smtp_printf("421 %s\r\n", FALSE, message);
059ec3d9 1652
bd8fbe36 1653for (;;) switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
059ec3d9 1654 {
60d10ce7 1655 case EOF_CMD:
db57e575 1656 return;
059ec3d9 1657
60d10ce7 1658 case QUIT_CMD:
db57e575
JH
1659 smtp_printf("221 %s closing connection\r\n", FALSE, smtp_active_hostname);
1660 mac_smtp_fflush();
1661 return;
059ec3d9 1662
60d10ce7 1663 case RSET_CMD:
db57e575
JH
1664 smtp_printf("250 Reset OK\r\n", FALSE);
1665 break;
059ec3d9 1666
60d10ce7 1667 default:
db57e575
JH
1668 smtp_printf("421 %s\r\n", FALSE, message);
1669 break;
059ec3d9
PH
1670 }
1671}
1672
1673
1674
1675
1676/*************************************************
1677* Set up connection info for logging *
1678*************************************************/
1679
1680/* This function is called when logging information about an SMTP connection.
1681It sets up appropriate source information, depending on the type of connection.
dac79d3e
PH
1682If sender_fullhost is NULL, we are at a very early stage of the connection;
1683just use the IP address.
059ec3d9
PH
1684
1685Argument: none
1686Returns: a string describing the connection
1687*/
1688
1689uschar *
1690smtp_get_connection_info(void)
1691{
f5d25c2b
JH
1692const uschar * hostname = sender_fullhost
1693 ? sender_fullhost : sender_host_address;
dac79d3e 1694
059ec3d9 1695if (host_checking)
dac79d3e 1696 return string_sprintf("SMTP connection from %s", hostname);
059ec3d9
PH
1697
1698if (sender_host_unknown || sender_host_notsocket)
1699 return string_sprintf("SMTP connection from %s", sender_ident);
1700
1701if (is_inetd)
dac79d3e 1702 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
059ec3d9 1703
6c6d6e48 1704if (LOGGING(incoming_interface) && interface_address != NULL)
dac79d3e 1705 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
059ec3d9
PH
1706 interface_address, interface_port);
1707
dac79d3e 1708return string_sprintf("SMTP connection from %s", hostname);
059ec3d9
PH
1709}
1710
1711
1712
e45a1c37 1713#ifdef SUPPORT_TLS
887291d2
JH
1714/* Append TLS-related information to a log line
1715
1716Arguments:
acec9514 1717 g String under construction: allocated string to extend, or NULL
887291d2
JH
1718
1719Returns: Allocated string or NULL
1720*/
acec9514
JH
1721static gstring *
1722s_tlslog(gstring * g)
e45a1c37 1723{
acec9514
JH
1724if (LOGGING(tls_cipher) && tls_in.cipher)
1725 g = string_append(g, 2, US" X=", tls_in.cipher);
1726if (LOGGING(tls_certificate_verified) && tls_in.cipher)
1727 g = string_append(g, 2, US" CV=", tls_in.certificate_verified? "yes":"no");
1728if (LOGGING(tls_peerdn) && tls_in.peerdn)
1729 g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
1730if (LOGGING(tls_sni) && tls_in.sni)
1731 g = string_append(g, 3, US" SNI=\"", string_printing(tls_in.sni), US"\"");
1732return g;
e45a1c37
JH
1733}
1734#endif
1735
059ec3d9 1736/*************************************************
b4ed4da0
PH
1737* Log lack of MAIL if so configured *
1738*************************************************/
1739
1740/* This function is called when an SMTP session ends. If the log selector
1741smtp_no_mail is set, write a log line giving some details of what has happened
1742in the SMTP session.
1743
1744Arguments: none
1745Returns: nothing
1746*/
1747
1748void
1749smtp_log_no_mail(void)
1750{
acec9514
JH
1751int i;
1752uschar * sep, * s;
1753gstring * g = NULL;
b4ed4da0 1754
6c6d6e48 1755if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
b4ed4da0
PH
1756 return;
1757
db57e575 1758if (sender_host_authenticated)
b4ed4da0 1759 {
acec9514
JH
1760 g = string_append(g, 2, US" A=", sender_host_authenticated);
1761 if (authenticated_id) g = string_append(g, 2, US":", authenticated_id);
b4ed4da0
PH
1762 }
1763
1764#ifdef SUPPORT_TLS
acec9514 1765g = s_tlslog(g);
3f0945ff 1766#endif
b4ed4da0 1767
acec9514
JH
1768sep = smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE ? US" C=..." : US" C=";
1769
b4ed4da0 1770for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
b4ed4da0
PH
1771 if (smtp_connection_had[i] != SCH_NONE)
1772 {
acec9514 1773 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
b4ed4da0
PH
1774 sep = US",";
1775 }
b4ed4da0
PH
1776
1777for (i = 0; i < smtp_ch_index; i++)
1778 {
acec9514 1779 g = string_append(g, 2, sep, smtp_names[smtp_connection_had[i]]);
b4ed4da0
PH
1780 sep = US",";
1781 }
1782
acec9514
JH
1783if (!(s = string_from_gstring(g))) s = US"";
1784
a2673768
JH
1785log_write(0, LOG_MAIN, "no MAIL in %sSMTP connection from %s D=%s%s",
1786 tcp_in_fastopen ? US"TFO " : US"",
0f1a8658 1787 host_and_ident(FALSE), string_timesince(&smtp_connection_start), s);
b4ed4da0
PH
1788}
1789
1790
a09f2942
JH
1791/* Return list of recent smtp commands */
1792
1793uschar *
1794smtp_cmd_hist(void)
1795{
acec9514
JH
1796int i;
1797gstring * list = NULL;
1798uschar * s;
a09f2942
JH
1799
1800for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1801 if (smtp_connection_had[i] != SCH_NONE)
acec9514
JH
1802 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1803
a09f2942 1804for (i = 0; i < smtp_ch_index; i++)
acec9514
JH
1805 list = string_append_listele(list, ',', smtp_names[smtp_connection_had[i]]);
1806
1807s = string_from_gstring(list);
1808return s ? s : US"";
a09f2942
JH
1809}
1810
1811
1812
b4ed4da0
PH
1813
1814/*************************************************
059ec3d9
PH
1815* Check HELO line and set sender_helo_name *
1816*************************************************/
1817
1818/* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1819the domain name of the sending host, or an ip literal in square brackets. The
4c04137d 1820argument is placed in sender_helo_name, which is in malloc store, because it
059ec3d9
PH
1821must persist over multiple incoming messages. If helo_accept_junk is set, this
1822host is permitted to send any old junk (needed for some broken hosts).
1823Otherwise, helo_allow_chars can be used for rogue characters in general
1824(typically people want to let in underscores).
1825
1826Argument:
1827 s the data portion of the line (already past any white space)
1828
1829Returns: TRUE or FALSE
1830*/
1831
1832static BOOL
1833check_helo(uschar *s)
1834{
1835uschar *start = s;
1836uschar *end = s + Ustrlen(s);
1837BOOL yield = helo_accept_junk;
1838
1839/* Discard any previous helo name */
1840
2d0dc929 1841if (sender_helo_name)
059ec3d9
PH
1842 {
1843 store_free(sender_helo_name);
1844 sender_helo_name = NULL;
1845 }
1846
1847/* Skip tests if junk is permitted. */
1848
1849if (!yield)
db57e575 1850
059ec3d9
PH
1851 /* Allow the new standard form for IPv6 address literals, namely,
1852 [IPv6:....], and because someone is bound to use it, allow an equivalent
1853 IPv4 form. Allow plain addresses as well. */
1854
1855 if (*s == '[')
1856 {
1857 if (end[-1] == ']')
1858 {
1859 end[-1] = 0;
1860 if (strncmpic(s, US"[IPv6:", 6) == 0)
1861 yield = (string_is_ip_address(s+6, NULL) == 6);
1862 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1863 yield = (string_is_ip_address(s+6, NULL) == 4);
1864 else
1865 yield = (string_is_ip_address(s+1, NULL) != 0);
1866 end[-1] = ']';
1867 }
1868 }
1869
1870 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1871 that have been configured (usually underscore - sigh). */
1872
db57e575
JH
1873 else if (*s)
1874 for (yield = TRUE; *s; s++)
059ec3d9
PH
1875 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1876 Ustrchr(helo_allow_chars, *s) == NULL)
1877 {
1878 yield = FALSE;
1879 break;
1880 }
059ec3d9
PH
1881
1882/* Save argument if OK */
1883
1884if (yield) sender_helo_name = string_copy_malloc(start);
1885return yield;
1886}
1887
1888
1889
1890
1891
1892/*************************************************
1893* Extract SMTP command option *
1894*************************************************/
1895
ca86f471 1896/* This function picks the next option setting off the end of smtp_cmd_data. It
059ec3d9
PH
1897is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1898things that can appear there.
1899
1900Arguments:
1901 name point this at the name
1902 value point this at the data string
1903
1904Returns: TRUE if found an option
1905*/
1906
1907static BOOL
1908extract_option(uschar **name, uschar **value)
1909{
1910uschar *n;
ca86f471 1911uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
059ec3d9
PH
1912while (isspace(*v)) v--;
1913v[1] = 0;
d7a2c833
JH
1914while (v > smtp_cmd_data && *v != '=' && !isspace(*v))
1915 {
1916 /* Take care to not stop at a space embedded in a quoted local-part */
1917
1918 if (*v == '"') do v--; while (*v != '"' && v > smtp_cmd_data+1);
1919 v--;
1920 }
059ec3d9
PH
1921
1922n = v;
fd98a5c6 1923if (*v == '=')
a2673768 1924 {
fd98a5c6
JH
1925 while(isalpha(n[-1])) n--;
1926 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1927 if (!isspace(n[-1])) return FALSE;
1928 n[-1] = 0;
a2673768 1929 }
fd98a5c6 1930else
a2673768 1931 {
fd98a5c6
JH
1932 n++;
1933 if (v == smtp_cmd_data) return FALSE;
a2673768 1934 }
059ec3d9 1935*v++ = 0;
fd98a5c6 1936*name = n;
059ec3d9
PH
1937*value = v;
1938return TRUE;
1939}
1940
1941
1942
1943
1944
059ec3d9
PH
1945/*************************************************
1946* Reset for new message *
1947*************************************************/
1948
1949/* This function is called whenever the SMTP session is reset from
1950within either of the setup functions.
1951
1952Argument: the stacking pool storage reset point
1953Returns: nothing
1954*/
1955
1956static void
1957smtp_reset(void *reset_point)
1958{
059ec3d9
PH
1959recipients_list = NULL;
1960rcpt_count = rcpt_defer_count = rcpt_fail_count =
1961 raw_recipients_count = recipients_count = recipients_list_max = 0;
2e0c1448 1962message_linecount = 0;
059ec3d9 1963message_size = -1;
71fafd95 1964acl_added_headers = NULL;
e7568d51 1965acl_removed_headers = NULL;
059ec3d9 1966queue_only_policy = FALSE;
2679d413
PH
1967rcpt_smtp_response = NULL;
1968rcpt_smtp_response_same = TRUE;
1969rcpt_in_progress = FALSE;
69358f02 1970deliver_freeze = FALSE; /* Can be set by ACL */
6a3f1455 1971freeze_tell = freeze_tell_config; /* Can be set by ACL */
29aba418 1972fake_response = OK; /* Can be set by ACL */
6951ac6c 1973#ifdef WITH_CONTENT_SCAN
8523533c
TK
1974no_mbox_unspool = FALSE; /* Can be set by ACL */
1975#endif
69358f02 1976submission_mode = FALSE; /* Can be set by ACL */
f4ee74ac 1977suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
69358f02
PH
1978active_local_from_check = local_from_check; /* Can be set by ACL */
1979active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
90341c71
JH
1980sending_ip_address = NULL;
1981return_path = sender_address = NULL;
1982sender_data = NULL; /* Can be set by ACL */
1983deliver_localpart_orig = NULL;
1984deliver_domain_orig = NULL;
1985callout_address = NULL;
2fe1a124 1986submission_name = NULL; /* Can be set by ACL */
059ec3d9
PH
1987raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1988sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1989sender_verified_list = NULL; /* No senders verified */
1990memset(sender_address_cache, 0, sizeof(sender_address_cache));
1991memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
6c1c3d1d 1992
059ec3d9 1993authenticated_sender = NULL;
8523533c
TK
1994#ifdef EXPERIMENTAL_BRIGHTMAIL
1995bmi_run = 0;
1996bmi_verdicts = NULL;
1997#endif
90341c71 1998dnslist_domain = dnslist_matched = NULL;
80a47a2c 1999#ifndef DISABLE_DKIM
9e5d6b55 2000dkim_signers = NULL;
80a47a2c
TK
2001dkim_disable_verify = FALSE;
2002dkim_collect_input = FALSE;
f7572e5a 2003#endif
aa368db3
JH
2004dsn_ret = 0;
2005dsn_envid = NULL;
90341c71 2006deliver_host = deliver_host_address = NULL; /* Can be set by ACL */
aa368db3
JH
2007#ifndef DISABLE_PRDR
2008prdr_requested = FALSE;
2009#endif
7952eef9 2010#ifdef SUPPORT_SPF
8523533c
TK
2011spf_header_comment = NULL;
2012spf_received = NULL;
8e669ac1 2013spf_result = NULL;
8523533c
TK
2014spf_smtp_comment = NULL;
2015#endif
8c5d388a 2016#ifdef SUPPORT_I18N
d1a13eea
JH
2017message_smtputf8 = FALSE;
2018#endif
059ec3d9
PH
2019body_linecount = body_zerocount = 0;
2020
870f6ba8
TF
2021sender_rate = sender_rate_limit = sender_rate_period = NULL;
2022ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
2023 /* Note that ratelimiters_conn persists across resets. */
2024
38a0a95f 2025/* Reset message ACL variables */
47ca6d6c 2026
38a0a95f 2027acl_var_m = NULL;
059ec3d9
PH
2028
2029/* The message body variables use malloc store. They may be set if this is
2030not the first message in an SMTP session and the previous message caused them
2031to be referenced in an ACL. */
2032
90341c71 2033if (message_body)
059ec3d9
PH
2034 {
2035 store_free(message_body);
2036 message_body = NULL;
2037 }
2038
90341c71 2039if (message_body_end)
059ec3d9
PH
2040 {
2041 store_free(message_body_end);
2042 message_body_end = NULL;
2043 }
2044
2045/* Warning log messages are also saved in malloc store. They are saved to avoid
2046repetition in the same message, but it seems right to repeat them for different
4e88a19f 2047messages. */
059ec3d9 2048
90341c71 2049while (acl_warn_logged)
059ec3d9
PH
2050 {
2051 string_item *this = acl_warn_logged;
2052 acl_warn_logged = acl_warn_logged->next;
2053 store_free(this);
2054 }
90341c71 2055store_reset(reset_point);
059ec3d9
PH
2056}
2057
2058
2059
2060
2061
2062/*************************************************
2063* Initialize for incoming batched SMTP message *
2064*************************************************/
2065
2066/* This function is called from smtp_setup_msg() in the case when
2067smtp_batched_input is true. This happens when -bS is used to pass a whole batch
2068of messages in one file with SMTP commands between them. All errors must be
2069reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
2070relevant. After an error on a sender, or an invalid recipient, the remainder
2071of the message is skipped. The value of received_protocol is already set.
2072
2073Argument: none
2074Returns: > 0 message successfully started (reached DATA)
2075 = 0 QUIT read or end of file reached
2076 < 0 should not occur
2077*/
2078
2079static int
2080smtp_setup_batch_msg(void)
2081{
2082int done = 0;
2083void *reset_point = store_get(0);
2084
2085/* Save the line count at the start of each transaction - single commands
2086like HELO and RSET count as whole transactions. */
2087
2088bsmtp_transaction_linecount = receive_linecount;
2089
2090if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
2091
57cc2785 2092cancel_cutthrough_connection(TRUE, US"smtp_setup_batch_msg");
059ec3d9
PH
2093smtp_reset(reset_point); /* Reset for start of message */
2094
2095/* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
2096value. The values are 2 larger than the required yield of the function. */
2097
2098while (done <= 0)
2099 {
2100 uschar *errmess;
2101 uschar *recipient = NULL;
2102 int start, end, sender_domain, recipient_domain;
2103
bd8fbe36 2104 switch(smtp_read_command(FALSE, GETC_BUFFER_UNLIMITED))
059ec3d9
PH
2105 {
2106 /* The HELO/EHLO commands set sender_address_helo if they have
2107 valid data; otherwise they are ignored, except that they do
2108 a reset of the state. */
2109
2110 case HELO_CMD:
2111 case EHLO_CMD:
2112
db57e575
JH
2113 check_helo(smtp_cmd_data);
2114 /* Fall through */
059ec3d9
PH
2115
2116 case RSET_CMD:
db57e575
JH
2117 cancel_cutthrough_connection(TRUE, US"RSET received");
2118 smtp_reset(reset_point);
2119 bsmtp_transaction_linecount = receive_linecount;
2120 break;
059ec3d9
PH
2121
2122
2123 /* The MAIL FROM command requires an address as an operand. All we
2124 do here is to parse it for syntactic correctness. The form "<>" is
2125 a special case which converts into an empty string. The start/end
2126 pointers in the original are not used further for this address, as
2127 it is the canonical extracted address which is all that is kept. */
2128
2129 case MAIL_CMD:
db57e575
JH
2130 smtp_mailcmd_count++; /* Count for no-mail log */
2131 if (sender_address != NULL)
2132 /* The function moan_smtp_batch() does not return. */
2133 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
059ec3d9 2134
db57e575
JH
2135 if (smtp_cmd_data[0] == 0)
2136 /* The function moan_smtp_batch() does not return. */
2137 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
059ec3d9 2138
db57e575 2139 /* Reset to start of message */
059ec3d9 2140
db57e575
JH
2141 cancel_cutthrough_connection(TRUE, US"MAIL received");
2142 smtp_reset(reset_point);
059ec3d9 2143
db57e575 2144 /* Apply SMTP rewrite */
059ec3d9 2145
db57e575
JH
2146 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
2147 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
2148 US"", global_rewrite_rules) : smtp_cmd_data;
059ec3d9 2149
db57e575 2150 /* Extract the address; the TRUE flag allows <> as valid */
059ec3d9 2151
db57e575
JH
2152 raw_sender =
2153 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
2154 TRUE);
059ec3d9 2155
db57e575
JH
2156 if (!raw_sender)
2157 /* The function moan_smtp_batch() does not return. */
2158 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
059ec3d9 2159
db57e575 2160 sender_address = string_copy(raw_sender);
059ec3d9 2161
db57e575 2162 /* Qualify unqualified sender addresses if permitted to do so. */
059ec3d9 2163
db57e575
JH
2164 if ( !sender_domain
2165 && sender_address[0] != 0 && sender_address[0] != '@')
2166 if (allow_unqualified_sender)
2167 {
2168 sender_address = rewrite_address_qualify(sender_address, FALSE);
2169 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
2170 "and rewritten\n", raw_sender);
2171 }
2172 /* The function moan_smtp_batch() does not return. */
2173 else
2174 moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
2175 "a domain");
2176 break;
059ec3d9
PH
2177
2178
2179 /* The RCPT TO command requires an address as an operand. All we do
2180 here is to parse it for syntactic correctness. There may be any number
2181 of RCPT TO commands, specifying multiple senders. We build them all into
2182 a data structure that is in argc/argv format. The start/end values
2183 given by parse_extract_address are not used, as we keep only the
2184 extracted address. */
2185
2186 case RCPT_CMD:
db57e575
JH
2187 if (!sender_address)
2188 /* The function moan_smtp_batch() does not return. */
2189 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
059ec3d9 2190
db57e575
JH
2191 if (smtp_cmd_data[0] == 0)
2192 /* The function moan_smtp_batch() does not return. */
2193 moan_smtp_batch(smtp_cmd_buffer,
2194 "501 RCPT TO must have an address operand");
059ec3d9 2195
db57e575 2196 /* Check maximum number allowed */
059ec3d9 2197
db57e575
JH
2198 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
2199 /* The function moan_smtp_batch() does not return. */
2200 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
2201 recipients_max_reject? "552": "452");
059ec3d9 2202
db57e575
JH
2203 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
2204 recipient address */
059ec3d9 2205
db57e575
JH
2206 recipient = rewrite_existflags & rewrite_smtp
2207 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
2208 global_rewrite_rules)
2209 : smtp_cmd_data;
059ec3d9 2210
db57e575
JH
2211 recipient = parse_extract_address(recipient, &errmess, &start, &end,
2212 &recipient_domain, FALSE);
059ec3d9 2213
db57e575
JH
2214 if (!recipient)
2215 /* The function moan_smtp_batch() does not return. */
2216 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
059ec3d9 2217
db57e575
JH
2218 /* If the recipient address is unqualified, qualify it if permitted. Then
2219 add it to the list of recipients. */
059ec3d9 2220
db57e575
JH
2221 if (!recipient_domain)
2222 if (allow_unqualified_recipient)
2223 {
2224 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
2225 recipient);
2226 recipient = rewrite_address_qualify(recipient, TRUE);
2227 }
2228 /* The function moan_smtp_batch() does not return. */
2229 else
2230 moan_smtp_batch(smtp_cmd_buffer,
2231 "501 recipient address must contain a domain");
2232
2233 receive_add_recipient(recipient, -1);
2234 break;
059ec3d9
PH
2235
2236
2237 /* The DATA command is legal only if it follows successful MAIL FROM
2238 and RCPT TO commands. This function is complete when a valid DATA
2239 command is encountered. */
2240
2241 case DATA_CMD:
db57e575
JH
2242 if (!sender_address || recipients_count <= 0)
2243 /* The function moan_smtp_batch() does not return. */
2244 if (!sender_address)
2245 moan_smtp_batch(smtp_cmd_buffer,
2246 "503 MAIL FROM:<sender> command must precede DATA");
2247 else
2248 moan_smtp_batch(smtp_cmd_buffer,
2249 "503 RCPT TO:<recipient> must precede DATA");
059ec3d9 2250 else
db57e575
JH
2251 {
2252 done = 3; /* DATA successfully achieved */
2253 message_ended = END_NOTENDED; /* Indicate in middle of message */
2254 }
2255 break;
059ec3d9
PH
2256
2257
2258 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
2259
2260 case VRFY_CMD:
2261 case EXPN_CMD:
2262 case HELP_CMD:
2263 case NOOP_CMD:
2264 case ETRN_CMD:
db57e575
JH
2265 bsmtp_transaction_linecount = receive_linecount;
2266 break;
059ec3d9
PH
2267
2268
2269 case EOF_CMD:
2270 case QUIT_CMD:
db57e575
JH
2271 done = 2;
2272 break;
059ec3d9
PH
2273
2274
2275 case BADARG_CMD:
db57e575
JH
2276 /* The function moan_smtp_batch() does not return. */
2277 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
2278 break;
059ec3d9
PH
2279
2280
2281 case BADCHAR_CMD:
db57e575
JH
2282 /* The function moan_smtp_batch() does not return. */
2283 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
2284 break;
059ec3d9
PH
2285
2286
2287 default:
db57e575
JH
2288 /* The function moan_smtp_batch() does not return. */
2289 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
2290 break;
059ec3d9
PH
2291 }
2292 }
2293
2294return done - 2; /* Convert yield values */
2295}
2296
2297
2298
2299
cf0c6164
JH
2300static BOOL
2301smtp_log_tls_fail(uschar * errstr)
2302{
2303uschar * conn_info = smtp_get_connection_info();
2304
2305if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5;
2306/* I'd like to get separated H= here, but too hard for now */
2307
2308log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr);
2309return FALSE;
2310}
2311
2312
a2673768
JH
2313
2314
2315#ifdef TCP_FASTOPEN
2316static void
2317tfo_in_check(void)
2318{
2319# ifdef TCP_INFO
2320struct tcp_info tinfo;
2321socklen_t len = sizeof(tinfo);
2322
2323if ( getsockopt(fileno(smtp_out), IPPROTO_TCP, TCP_INFO, &tinfo, &len) == 0
2324 && tinfo.tcpi_state == TCP_SYN_RECV
2325 )
2326 {
1ccd5f67 2327 DEBUG(D_receive) debug_printf("TCP_FASTOPEN mode connection (state TCP_SYN_RECV)\n");
a2673768
JH
2328 tcp_in_fastopen = TRUE;
2329 }
2330# endif
2331}
2332#endif
2333
2334
059ec3d9
PH
2335/*************************************************
2336* Start an SMTP session *
2337*************************************************/
2338
2339/* This function is called at the start of an SMTP session. Thereafter,
2340smtp_setup_msg() is called to initiate each separate message. This
2341function does host-specific testing, and outputs the banner line.
2342
2343Arguments: none
2344Returns: FALSE if the session can not continue; something has
2345 gone wrong, or the connection to the host is blocked
2346*/
2347
2348BOOL
2349smtp_start_session(void)
2350{
acec9514 2351int esclen;
4e88a19f
PH
2352uschar *user_msg, *log_msg;
2353uschar *code, *esc;
acec9514
JH
2354uschar *p, *s;
2355gstring * ss;
059ec3d9 2356
0f1a8658 2357gettimeofday(&smtp_connection_start, NULL);
b4ed4da0
PH
2358for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2359 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2360smtp_ch_index = 0;
2361
00f00ca5
PH
2362/* Default values for certain variables */
2363
059ec3d9 2364helo_seen = esmtp = helo_accept_junk = FALSE;
b4ed4da0 2365smtp_mailcmd_count = 0;
059ec3d9
PH
2366count_nonmail = TRUE_UNSET;
2367synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2368smtp_delay_mail = smtp_rlm_base;
2369auth_advertised = FALSE;
2370pipelining_advertised = FALSE;
cf8b11a5 2371pipelining_enable = TRUE;
059ec3d9 2372sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
8f128379 2373smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
059ec3d9 2374
33d73e3b
PH
2375/* If receiving by -bs from a trusted user, or testing with -bh, we allow
2376authentication settings from -oMaa to remain in force. */
2377
2378if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
059ec3d9
PH
2379authenticated_by = NULL;
2380
2381#ifdef SUPPORT_TLS
817d9f57 2382tls_in.cipher = tls_in.peerdn = NULL;
9d1c15ef
JH
2383tls_in.ourcert = tls_in.peercert = NULL;
2384tls_in.sni = NULL;
44662487 2385tls_in.ocsp = OCSP_NOT_REQ;
059ec3d9
PH
2386tls_advertised = FALSE;
2387#endif
6c1c3d1d 2388dsn_advertised = FALSE;
8c5d388a 2389#ifdef SUPPORT_I18N
d1a13eea
JH
2390smtputf8_advertised = FALSE;
2391#endif
059ec3d9
PH
2392
2393/* Reset ACL connection variables */
2394
38a0a95f 2395acl_var_c = NULL;
059ec3d9 2396
ca86f471 2397/* Allow for trailing 0 in the command and data buffers. */
3ee512ff 2398
bd8fbe36 2399if (!(smtp_cmd_buffer = US malloc(2*SMTP_CMD_BUFFER_SIZE + 2)))
059ec3d9
PH
2400 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2401 "malloc() failed for SMTP command buffer");
40c90bca 2402
2416c261 2403smtp_cmd_buffer[0] = 0;
bd8fbe36 2404smtp_data_buffer = smtp_cmd_buffer + SMTP_CMD_BUFFER_SIZE + 1;
059ec3d9
PH
2405
2406/* For batched input, the protocol setting can be overridden from the
2407command line by a trusted caller. */
2408
2409if (smtp_batched_input)
2410 {
40c90bca 2411 if (!received_protocol) received_protocol = US"local-bsmtp";
059ec3d9
PH
2412 }
2413
2414/* For non-batched SMTP input, the protocol setting is forced here. It will be
2415reset later if any of EHLO/AUTH/STARTTLS are received. */
2416
2417else
2418 received_protocol =
e524074d 2419 (sender_host_address ? protocols : protocols_local) [pnormal];
059ec3d9
PH
2420
2421/* Set up the buffer for inputting using direct read() calls, and arrange to
2422call the local functions instead of the standard C ones. */
2423
5903c6ff 2424if (!(smtp_inbuffer = US malloc(IN_BUFFER_SIZE)))
059ec3d9 2425 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
40c90bca 2426
059ec3d9 2427receive_getc = smtp_getc;
0d81dabc 2428receive_getbuf = smtp_getbuf;
584e96c6 2429receive_get_cache = smtp_get_cache;
059ec3d9
PH
2430receive_ungetc = smtp_ungetc;
2431receive_feof = smtp_feof;
2432receive_ferror = smtp_ferror;
58eb016e 2433receive_smtp_buffered = smtp_buffered;
059ec3d9
PH
2434smtp_inptr = smtp_inend = smtp_inbuffer;
2435smtp_had_eof = smtp_had_error = 0;
2436
2437/* Set up the message size limit; this may be host-specific */
2438
d45b1de8 2439thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
db57e575 2440if (expand_string_message)
059ec3d9
PH
2441 {
2442 if (thismessage_size_limit == -1)
2443 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2444 "%s", expand_string_message);
2445 else
2446 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2447 "%s", expand_string_message);
2448 smtp_closedown(US"Temporary local problem - please try later");
2449 return FALSE;
2450 }
2451
2452/* When a message is input locally via the -bs or -bS options, sender_host_
2453unknown is set unless -oMa was used to force an IP address, in which case it
2454is checked like a real remote connection. When -bs is used from inetd, this
2455flag is not set, causing the sending host to be checked. The code that deals
2456with IP source routing (if configured) is never required for -bs or -bS and
2457the flag sender_host_notsocket is used to suppress it.
2458
2459If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2460reserve for certain hosts and/or networks. */
2461
2462if (!sender_host_unknown)
2463 {
2464 int rc;
2465 BOOL reserved_host = FALSE;
2466
2467 /* Look up IP options (source routing info) on the socket if this is not an
2468 -oMa "host", and if any are found, log them and drop the connection.
2469
2470 Linux (and others now, see below) is different to everyone else, so there
2471 has to be some conditional compilation here. Versions of Linux before 2.1.15
2472 used a structure whose name was "options". Somebody finally realized that
2473 this name was silly, and it got changed to "ip_options". I use the
2474 newer name here, but there is a fudge in the script that sets up os.h
2475 to define a macro in older Linux systems.
2476
2477 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2478 glibc 2, which has chosen ip_opts for the structure name. This is now
2479 really a glibc thing rather than a Linux thing, so the condition name
2480 has been changed to reflect this. It is relevant also to GNU/Hurd.
2481
2482 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2483 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2484 a special macro defined in the os.h file.
2485
2486 Some DGUX versions on older hardware appear not to support IP options at
2487 all, so there is now a general macro which can be set to cut out this
2488 support altogether.
2489
2490 How to do this properly in IPv6 is not yet known. */
2491
2492 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2493
2494 #ifdef GLIBC_IP_OPTIONS
2495 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2496 #define OPTSTYLE 1
2497 #else
2498 #define OPTSTYLE 2
2499 #endif
2500 #elif defined DARWIN_IP_OPTIONS
2501 #define OPTSTYLE 2
2502 #else
2503 #define OPTSTYLE 3
2504 #endif
2505
2506 if (!host_checking && !sender_host_notsocket)
2507 {
2508 #if OPTSTYLE == 1
36a3b041 2509 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
059ec3d9
PH
2510 struct ip_options *ipopt = store_get(optlen);
2511 #elif OPTSTYLE == 2
2512 struct ip_opts ipoptblock;
2513 struct ip_opts *ipopt = &ipoptblock;
36a3b041 2514 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
059ec3d9
PH
2515 #else
2516 struct ipoption ipoptblock;
2517 struct ipoption *ipopt = &ipoptblock;
36a3b041 2518 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
059ec3d9
PH
2519 #endif
2520
2521 /* Occasional genuine failures of getsockopt() have been seen - for
2522 example, "reset by peer". Therefore, just log and give up on this
2523 call, unless the error is ENOPROTOOPT. This error is given by systems
2524 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2525 of writing. So for that error, carry on - we just can't do an IP options
2526 check. */
2527
2528 DEBUG(D_receive) debug_printf("checking for IP options\n");
2529
5903c6ff 2530 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, US (ipopt),
059ec3d9
PH
2531 &optlen) < 0)
2532 {
2533 if (errno != ENOPROTOOPT)
2534 {
2535 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2536 host_and_ident(FALSE), strerror(errno));
925ac8e4 2537 smtp_printf("451 SMTP service not available\r\n", FALSE);
059ec3d9
PH
2538 return FALSE;
2539 }
2540 }
2541
2542 /* Deal with any IP options that are set. On the systems I have looked at,
2543 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2544 more logging data than will fit in big_buffer. Nevertheless, after somebody
2545 questioned this code, I've added in some paranoid checking. */
2546
2547 else if (optlen > 0)
2548 {
2549 uschar *p = big_buffer;
2550 uschar *pend = big_buffer + big_buffer_size;
2551 uschar *opt, *adptr;
2552 int optcount;
2553 struct in_addr addr;
2554
2555 #if OPTSTYLE == 1
5903c6ff 2556 uschar *optstart = US (ipopt->__data);
059ec3d9 2557 #elif OPTSTYLE == 2
5903c6ff 2558 uschar *optstart = US (ipopt->ip_opts);
059ec3d9 2559 #else
5903c6ff 2560 uschar *optstart = US (ipopt->ipopt_list);
059ec3d9
PH
2561 #endif
2562
2563 DEBUG(D_receive) debug_printf("IP options exist\n");
2564
2565 Ustrcpy(p, "IP options on incoming call:");
2566 p += Ustrlen(p);
2567
2568 for (opt = optstart; opt != NULL &&
5903c6ff 2569 opt < US (ipopt) + optlen;)
059ec3d9
PH
2570 {
2571 switch (*opt)
2572 {
2573 case IPOPT_EOL:
2574 opt = NULL;
2575 break;
2576
2577 case IPOPT_NOP:
2578 opt++;
2579 break;
2580
2581 case IPOPT_SSRR:
2582 case IPOPT_LSRR:
2583 if (!string_format(p, pend-p, " %s [@%s",
2584 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2585 #if OPTSTYLE == 1
2586 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2587 #elif OPTSTYLE == 2
2588 inet_ntoa(ipopt->ip_dst)))
2589 #else
2590 inet_ntoa(ipopt->ipopt_dst)))
2591 #endif
2592 {
2593 opt = NULL;
2594 break;
2595 }
2596
2597 p += Ustrlen(p);
2598 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2599 adptr = opt + 3;
2600 while (optcount-- > 0)
2601 {
2602 memcpy(&addr, adptr, sizeof(addr));
2603 if (!string_format(p, pend - p - 1, "%s%s",
2604 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2605 {
2606 opt = NULL;
2607 break;
2608 }
2609 p += Ustrlen(p);
2610 adptr += sizeof(struct in_addr);
2611 }
2612 *p++ = ']';
2613 opt += opt[1];
2614 break;
2615
2616 default:
2617 {
2618 int i;
2619 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2620 Ustrcat(p, "[ ");
2621 p += 2;
2622 for (i = 0; i < opt[1]; i++)
5976eb99 2623 p += sprintf(CS p, "%2.2x ", opt[i]);
059ec3d9
PH
2624 *p++ = ']';
2625 }
2626 opt += opt[1];
2627 break;
2628 }
2629 }
2630
2631 *p = 0;
2632 log_write(0, LOG_MAIN, "%s", big_buffer);
2633
2634 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2635
2636 log_write(0, LOG_MAIN|LOG_REJECT,
2637 "connection from %s refused (IP options)", host_and_ident(FALSE));
2638
925ac8e4 2639 smtp_printf("554 SMTP service not available\r\n", FALSE);
059ec3d9
PH
2640 return FALSE;
2641 }
2642
2643 /* Length of options = 0 => there are no options */
2644
2645 else DEBUG(D_receive) debug_printf("no IP options found\n");
2646 }
2647 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2648
2649 /* Set keep-alive in socket options. The option is on by default. This
2650 setting is an attempt to get rid of some hanging connections that stick in
2651 read() when the remote end (usually a dialup) goes away. */
2652
2653 if (smtp_accept_keepalive && !sender_host_notsocket)
2654 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2655
2656 /* If the current host matches host_lookup, set the name by doing a
2657 reverse lookup. On failure, sender_host_name will be NULL and
2658 host_lookup_failed will be TRUE. This may or may not be serious - optional
2659 checks later. */
2660
2661 if (verify_check_host(&host_lookup) == OK)
2662 {
2663 (void)host_name_lookup();
2664 host_build_sender_fullhost();
2665 }
2666
2667 /* Delay this until we have the full name, if it is looked up. */
2668
2669 set_process_info("handling incoming connection from %s",
2670 host_and_ident(FALSE));
2671
1ad6489e
JH
2672 /* Expand smtp_receive_timeout, if needed */
2673
2674 if (smtp_receive_timeout_s)
2675 {
2676 uschar * exp;
2677 if ( !(exp = expand_string(smtp_receive_timeout_s))
2678 || !(*exp)
2679 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2680 )
2681 log_write(0, LOG_MAIN|LOG_PANIC,
2682 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2683 }
2684
059ec3d9
PH
2685 /* Test for explicit connection rejection */
2686
2687 if (verify_check_host(&host_reject_connection) == OK)
2688 {
2689 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2690 "from %s (host_reject_connection)", host_and_ident(FALSE));
925ac8e4 2691 smtp_printf("554 SMTP service not available\r\n", FALSE);
059ec3d9
PH
2692 return FALSE;
2693 }
2694
afb3eaaf
PH
2695 /* Test with TCP Wrappers if so configured. There is a problem in that
2696 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2697 such as disks dying. In these cases, it is desirable to reject with a 4xx
2698 error instead of a 5xx error. There isn't a "right" way to detect such
2699 problems. The following kludge is used: errno is zeroed before calling
2700 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2701 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2702 not exist). */
059ec3d9 2703
1811cb4c 2704#ifdef USE_TCP_WRAPPERS
afb3eaaf 2705 errno = 0;
1811cb4c 2706 if (!(tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name)))
5dc43717
JJ
2707 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2708 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2709 expand_string_message);
1811cb4c 2710
5dc43717 2711 if (!hosts_ctl(tcp_wrappers_name,
1811cb4c
JH
2712 sender_host_name ? CS sender_host_name : STRING_UNKNOWN,
2713 sender_host_address ? CS sender_host_address : STRING_UNKNOWN,
2714 sender_ident ? CS sender_ident : STRING_UNKNOWN))
059ec3d9 2715 {
afb3eaaf
PH
2716 if (errno == 0 || errno == ENOENT)
2717 {
2718 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2719 log_write(L_connection_reject,
2720 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2721 "(tcp wrappers)", host_and_ident(FALSE));
925ac8e4 2722 smtp_printf("554 SMTP service not available\r\n", FALSE);
afb3eaaf
PH
2723 }
2724 else
2725 {
2726 int save_errno = errno;
2727 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2728 "errno value %d\n", save_errno);
2729 log_write(L_connection_reject,
2730 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2731 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
925ac8e4 2732 smtp_printf("451 Temporary local problem - please try later\r\n", FALSE);
afb3eaaf 2733 }
059ec3d9
PH
2734 return FALSE;
2735 }
1811cb4c 2736#endif
059ec3d9 2737
b01dd148
PH
2738 /* Check for reserved slots. The value of smtp_accept_count has already been
2739 incremented to include this process. */
059ec3d9
PH
2740
2741 if (smtp_accept_max > 0 &&
b01dd148 2742 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
059ec3d9
PH
2743 {
2744 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2745 {
2746 log_write(L_connection_reject,
2747 LOG_MAIN, "temporarily refused connection from %s: not in "
2748 "reserve list: connected=%d max=%d reserve=%d%s",
b01dd148 2749 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
059ec3d9
PH
2750 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2751 smtp_printf("421 %s: Too many concurrent SMTP connections; "
925ac8e4 2752 "please try again later\r\n", FALSE, smtp_active_hostname);
059ec3d9
PH
2753 return FALSE;
2754 }
2755 reserved_host = TRUE;
2756 }
2757
2758 /* If a load level above which only messages from reserved hosts are
2759 accepted is set, check the load. For incoming calls via the daemon, the
2760 check is done in the superior process if there are no reserved hosts, to
2761 save a fork. In all cases, the load average will already be available
2762 in a global variable at this point. */
2763
2764 if (smtp_load_reserve >= 0 &&
2765 load_average > smtp_load_reserve &&
2766 !reserved_host &&
2767 verify_check_host(&smtp_reserve_hosts) != OK)
2768 {
2769 log_write(L_connection_reject,
2770 LOG_MAIN, "temporarily refused connection from %s: not in "
2771 "reserve list and load average = %.2f", host_and_ident(FALSE),
2772 (double)load_average/1000.0);
925ac8e4 2773 smtp_printf("421 %s: Too much load; please try again later\r\n", FALSE,
059ec3d9
PH
2774 smtp_active_hostname);
2775 return FALSE;
2776 }
2777
2778 /* Determine whether unqualified senders or recipients are permitted
2779 for this host. Unfortunately, we have to do this every time, in order to
2780 set the flags so that they can be inspected when considering qualifying
2781 addresses in the headers. For a site that permits no qualification, this
2782 won't take long, however. */
2783
2784 allow_unqualified_sender =
2785 verify_check_host(&sender_unqualified_hosts) == OK;
2786
2787 allow_unqualified_recipient =
2788 verify_check_host(&recipient_unqualified_hosts) == OK;
2789
2790 /* Determine whether HELO/EHLO is required for this host. The requirement
2791 can be hard or soft. */
2792
2793 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2794 if (!helo_required)
2795 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2796
2797 /* Determine whether this hosts is permitted to send syntactic junk
2798 after a HELO or EHLO command. */
2799
2800 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2801 }
2802
2803/* For batch SMTP input we are now done. */
2804
2805if (smtp_batched_input) return TRUE;
2806
a3c86431
TL
2807/* If valid Proxy Protocol source is connecting, set up session.
2808 * Failure will not allow any SMTP function other than QUIT. */
1811cb4c
JH
2809
2810#ifdef SUPPORT_PROXY
a3c86431
TL
2811proxy_session = FALSE;
2812proxy_session_failed = FALSE;
2813if (check_proxy_protocol_host())
1811cb4c
JH
2814 setup_proxy_protocol_host();
2815#endif
2816
2817 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2818 smtps port for use with older style SSL MTAs. */
2819
2820#ifdef SUPPORT_TLS
69d8eed7
JH
2821 if (tls_in.on_connect)
2822 {
2823 if (tls_server_start(tls_require_ciphers, &user_msg) != OK)
2824 return smtp_log_tls_fail(user_msg);
2825 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
2826 }
a3c86431
TL
2827#endif
2828
1811cb4c 2829/* Run the connect ACL if it exists */
059ec3d9 2830
4e88a19f 2831user_msg = NULL;
3cc3f762 2832if (acl_smtp_connect)
059ec3d9
PH
2833 {
2834 int rc;
3cc3f762
JH
2835 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2836 &log_msg)) != OK)
059ec3d9 2837 {
3cc3f762 2838 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
059ec3d9
PH
2839 return FALSE;
2840 }
2841 }
2842
2843/* Output the initial message for a two-way SMTP connection. It may contain
2844newlines, which then cause a multi-line response to be given. */
2845
4e88a19f
PH
2846code = US"220"; /* Default status code */
2847esc = US""; /* Default extended status code */
2848esclen = 0; /* Length of esc */
2849
d4ff61d1 2850if (!user_msg)
4e88a19f 2851 {
d4ff61d1 2852 if (!(s = expand_string(smtp_banner)))
4e88a19f
PH
2853 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2854 "failed: %s", smtp_banner, expand_string_message);
2855 }
2856else
2857 {
2858 int codelen = 3;
2859 s = user_msg;
4f6ae5c3 2860 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
d6a96edc 2861 if (codelen > 4)
4e88a19f
PH
2862 {
2863 esc = code + 4;
2864 esclen = codelen - 4;
2865 }
2866 }
059ec3d9
PH
2867
2868/* Remove any terminating newlines; might as well remove trailing space too */
2869
2870p = s + Ustrlen(s);
2871while (p > s && isspace(p[-1])) p--;
2872*p = 0;
2873
2874/* It seems that CC:Mail is braindead, and assumes that the greeting message
2875is all contained in a single IP packet. The original code wrote out the
2876greeting using several calls to fprint/fputc, and on busy servers this could
2877cause it to be split over more than one packet - which caused CC:Mail to fall
2878over when it got the second part of the greeting after sending its first
2879command. Sigh. To try to avoid this, build the complete greeting message
2880first, and output it in one fell swoop. This gives a better chance of it
2881ending up as a single packet. */
2882
acec9514 2883ss = string_get(256);
059ec3d9
PH
2884
2885p = s;
2886do /* At least once, in case we have an empty string */
2887 {
2888 int len;
2889 uschar *linebreak = Ustrchr(p, '\n');
acec9514 2890 ss = string_catn(ss, code, 3);
db57e575 2891 if (!linebreak)
059ec3d9
PH
2892 {
2893 len = Ustrlen(p);
acec9514 2894 ss = string_catn(ss, US" ", 1);
059ec3d9
PH
2895 }
2896 else
2897 {
2898 len = linebreak - p;
acec9514 2899 ss = string_catn(ss, US"-", 1);
059ec3d9 2900 }
acec9514
JH
2901 ss = string_catn(ss, esc, esclen);
2902 ss = string_catn(ss, p, len);
2903 ss = string_catn(ss, US"\r\n", 2);
059ec3d9 2904 p += len;
db57e575 2905 if (linebreak) p++;
059ec3d9 2906 }
db57e575 2907while (*p);
059ec3d9 2908
059ec3d9
PH
2909/* Before we write the banner, check that there is no input pending, unless
2910this synchronisation check is disabled. */
2911
a14e5636 2912if (!check_sync())
059ec3d9 2913 {
40525d07
JH
2914 unsigned n = smtp_inend - smtp_inptr;
2915 if (n > 32) n = 32;
2916
a14e5636
PH
2917 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2918 "synchronization error (input sent without waiting for greeting): "
2919 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
40525d07 2920 string_printing(string_copyn(smtp_inptr, n)));
925ac8e4 2921 smtp_printf("554 SMTP synchronization error\r\n", FALSE);
a14e5636 2922 return FALSE;
059ec3d9
PH
2923 }
2924
2925/* Now output the banner */
2926
acec9514 2927smtp_printf("%s", FALSE, string_from_gstring(ss));
a2673768
JH
2928
2929/* Attempt to see if we sent the banner before the last ACK of the 3-way
2930handshake arrived. If so we must have managed a TFO. */
2931
2932#ifdef TCP_FASTOPEN
2933tfo_in_check();
2934#endif
2935
059ec3d9
PH
2936return TRUE;
2937}
2938
2939
2940
2941
2942
2943/*************************************************
2944* Handle SMTP syntax and protocol errors *
2945*************************************************/
2946
2947/* Write to the log for SMTP syntax errors in incoming commands, if configured
2948to do so. Then transmit the error response. The return value depends on the
2949number of syntax and protocol errors in this SMTP session.
2950
2951Arguments:
2952 type error type, given as a log flag bit
2953 code response code; <= 0 means don't send a response
2954 data data to reflect in the response (can be NULL)
2955 errmess the error message
2956
2957Returns: -1 limit of syntax/protocol errors NOT exceeded
2958 +1 limit of syntax/protocol errors IS exceeded
2959
2960These values fit in with the values of the "done" variable in the main
2961processing loop in smtp_setup_msg(). */
2962
2963static int
2964synprot_error(int type, int code, uschar *data, uschar *errmess)
2965{
2966int yield = -1;
2967
2968log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2969 (type == L_smtp_syntax_error)? "syntax" : "protocol",
3ee512ff 2970 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
059ec3d9
PH
2971
2972if (++synprot_error_count > smtp_max_synprot_errors)
2973 {
2974 yield = 1;
2975 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2976 "syntax or protocol errors (last command was \"%s\")",
0ebc4d69 2977 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
059ec3d9
PH
2978 }
2979
2980if (code > 0)
2981 {
925ac8e4
JH
2982 smtp_printf("%d%c%s%s%s\r\n", FALSE, code, yield == 1 ? '-' : ' ',
2983 data ? data : US"", data ? US": " : US"", errmess);
059ec3d9 2984 if (yield == 1)
925ac8e4 2985 smtp_printf("%d Too many syntax or protocol errors\r\n", FALSE, code);
059ec3d9
PH
2986 }
2987
2988return yield;
2989}
2990
2991
2992
2993
2994/*************************************************
059ec3d9
PH
2995* Send SMTP response, possibly multiline *
2996*************************************************/
2997
2998/* There are, it seems, broken clients out there that cannot handle multiline
2999responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
3000output nothing for non-final calls, and only the first line for anything else.
3001
3002Arguments:
a5bd321b 3003 code SMTP code, may involve extended status codes
d6a96edc 3004 codelen length of smtp code; if > 4 there's an ESC
059ec3d9
PH
3005 final FALSE if the last line isn't the final line
3006 msg message text, possibly containing newlines
3007
3008Returns: nothing
3009*/
3010
3011void
a5bd321b 3012smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
059ec3d9 3013{
a5bd321b
PH
3014int esclen = 0;
3015uschar *esc = US"";
3016
059ec3d9
PH
3017if (!final && no_multiline_responses) return;
3018
d6a96edc 3019if (codelen > 4)
a5bd321b
PH
3020 {
3021 esc = code + 4;
3022 esclen = codelen - 4;
3023 }
3024
2679d413
PH
3025/* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
3026have had the same. Note: this code is also present in smtp_printf(). It would
3027be tidier to have it only in one place, but when it was added, it was easier to
3028do it that way, so as not to have to mess with the code for the RCPT command,
3029which sometimes uses smtp_printf() and sometimes smtp_respond(). */
3030
3031if (rcpt_in_progress)
3032 {
3033 if (rcpt_smtp_response == NULL)
3034 rcpt_smtp_response = string_copy(msg);
3035 else if (rcpt_smtp_response_same &&
3036 Ustrcmp(rcpt_smtp_response, msg) != 0)
3037 rcpt_smtp_response_same = FALSE;
3038 rcpt_in_progress = FALSE;
3039 }
3040
e5de01f0 3041/* Now output the message, splitting it up into multiple lines if necessary.
925ac8e4
JH
3042We only handle pipelining these responses as far as nonfinal/final groups,
3043not the whole MAIL/RCPT/DATA response set. */
2679d413 3044
059ec3d9
PH
3045for (;;)
3046 {
3047 uschar *nl = Ustrchr(msg, '\n');
3048 if (nl == NULL)
3049 {
925ac8e4 3050 smtp_printf("%.3s%c%.*s%s\r\n", !final, code, final ? ' ':'-', esclen, esc, msg);
059ec3d9
PH
3051 return;
3052 }
3053 else if (nl[1] == 0 || no_multiline_responses)
3054 {
925ac8e4 3055 smtp_printf("%.3s%c%.*s%.*s\r\n", !final, code, final ? ' ':'-', esclen, esc,
a5bd321b 3056 (int)(nl - msg), msg);
059ec3d9
PH
3057 return;
3058 }
3059 else
3060 {
925ac8e4 3061 smtp_printf("%.3s-%.*s%.*s\r\n", TRUE, code, esclen, esc, (int)(nl - msg), msg);
059ec3d9
PH
3062 msg = nl + 1;
3063 while (isspace(*msg)) msg++;
3064 }
3065 }
3066}
3067
3068
3069
3070
3071/*************************************************
4e88a19f
PH
3072* Parse user SMTP message *
3073*************************************************/
3074
3075/* This function allows for user messages overriding the response code details
3076by providing a suitable response code string at the start of the message
3077user_msg. Check the message for starting with a response code and optionally an
3078extended status code. If found, check that the first digit is valid, and if so,
3079change the code pointer and length to use the replacement. An invalid code
3080causes a panic log; in this case, if the log messages is the same as the user
3081message, we must also adjust the value of the log message to show the code that
3082is actually going to be used (the original one).
3083
3084This function is global because it is called from receive.c as well as within
3085this module.
3086
d6a96edc
PH
3087Note that the code length returned includes the terminating whitespace
3088character, which is always included in the regex match.
3089
4e88a19f
PH
3090Arguments:
3091 code SMTP code, may involve extended status codes
d6a96edc 3092 codelen length of smtp code; if > 4 there's an ESC
4e88a19f
PH
3093 msg message text
3094 log_msg optional log message, to be adjusted with the new SMTP code
4f6ae5c3 3095 check_valid if true, verify the response code
4e88a19f
PH
3096
3097Returns: nothing
3098*/
3099
3100void
4f6ae5c3
JH
3101smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
3102 BOOL check_valid)
4e88a19f
PH
3103{
3104int n;
3105int ovector[3];
3106
4f6ae5c3 3107if (!msg || !*msg) return;
4e88a19f 3108
4f6ae5c3
JH
3109if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
3110 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
4e88a19f 3111
4f6ae5c3 3112if (check_valid && (*msg)[0] != (*code)[0])
4e88a19f
PH
3113 {
3114 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
3115 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
3116 if (log_msg != NULL && *log_msg == *msg)
3117 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
3118 }
3119else
3120 {
3121 *code = *msg;
3122 *codelen = ovector[1]; /* Includes final space */
3123 }
3124*msg += ovector[1]; /* Chop the code off the message */
3125return;
3126}
3127
3128
3129
3130
3131/*************************************************
059ec3d9
PH
3132* Handle an ACL failure *
3133*************************************************/
3134
3135/* This function is called when acl_check() fails. As well as calls from within
3136this module, it is called from receive.c for an ACL after DATA. It sorts out
5b6f7658 3137logging the incident, and sends the error response. A message containing
059ec3d9
PH
3138newlines is turned into a multiline SMTP response, but for logging, only the
3139first line is used.
3140
a5bd321b
PH
3141There's a table of default permanent failure response codes to use in
3142globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
3143defaults disabled in Exim. However, discussion in connection with RFC 821bis
3144(aka RFC 2821) has concluded that the response should be 252 in the disabled
3145state, because there are broken clients that try VRFY before RCPT. A 5xx
3146response should be given only when the address is positively known to be
4f6ae5c3
JH
3147undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
3148no explicit code, but if there is one we let it know best.
3149Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
a5bd321b
PH
3150
3151From Exim 4.63, it is possible to override the response code details by
3152providing a suitable response code string at the start of the message provided
3153in user_msg. The code's first digit is checked for validity.
059ec3d9
PH
3154
3155Arguments:
4f6ae5c3
JH
3156 where where the ACL was called from
3157 rc the failure code
3158 user_msg a message that can be included in an SMTP response
3159 log_msg a message for logging
059ec3d9
PH
3160
3161Returns: 0 in most cases
3162 2 if the failure code was FAIL_DROP, in which case the
3163 SMTP connection should be dropped (this value fits with the
3164 "done" variable in smtp_setup_msg() below)
3165*/
3166
3167int
3168smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
3169{
059ec3d9 3170BOOL drop = rc == FAIL_DROP;
a5bd321b 3171int codelen = 3;
a5bd321b 3172uschar *smtp_code;
059ec3d9
PH
3173uschar *lognl;
3174uschar *sender_info = US"";
64ffc24f 3175uschar *what =
8523533c 3176#ifdef WITH_CONTENT_SCAN
3cc3f762 3177 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
8e669ac1 3178#endif
3cc3f762
JH
3179 where == ACL_WHERE_PREDATA ? US"DATA" :
3180 where == ACL_WHERE_DATA ? US"after DATA" :
8ccd00b1 3181#ifndef DISABLE_PRDR
3cc3f762 3182 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
fd98a5c6 3183#endif
3cc3f762
JH
3184 smtp_cmd_data ?
3185 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
3186 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
059ec3d9
PH
3187
3188if (drop) rc = FAIL;
3189
4e88a19f 3190/* Set the default SMTP code, and allow a user message to change it. */
a5bd321b 3191
4f6ae5c3
JH
3192smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
3193smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
3194 where != ACL_WHERE_VRFY);
a5bd321b 3195
059ec3d9
PH
3196/* We used to have sender_address here; however, there was a bug that was not
3197updating sender_address after a rewrite during a verify. When this bug was
3198fixed, sender_address at this point became the rewritten address. I'm not sure
3199this is what should be logged, so I've changed to logging the unrewritten
3200address to retain backward compatibility. */
3201
8523533c 3202#ifndef WITH_CONTENT_SCAN
059ec3d9 3203if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
8523533c
TK
3204#else
3205if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
3206#endif
059ec3d9 3207 {
b98bb9ac
PP
3208 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
3209 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
3210 sender_host_authenticated ? US" A=" : US"",
3211 sender_host_authenticated ? sender_host_authenticated : US"",
3212 sender_host_authenticated && authenticated_id ? US":" : US"",
3213 sender_host_authenticated && authenticated_id ? authenticated_id : US""
3214 );
059ec3d9
PH
3215 }
3216
3217/* If there's been a sender verification failure with a specific message, and
3218we have not sent a response about it yet, do so now, as a preliminary line for
278c6e6c
PH
3219failures, but not defers. However, always log it for defer, and log it for fail
3220unless the sender_verify_fail log selector has been turned off. */
059ec3d9 3221
02b41d71 3222if (sender_verified_failed &&
059ec3d9
PH
3223 !testflag(sender_verified_failed, af_sverify_told))
3224 {
2679d413
PH
3225 BOOL save_rcpt_in_progress = rcpt_in_progress;
3226 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
3227
059ec3d9
PH
3228 setflag(sender_verified_failed, af_sverify_told);
3229
6c6d6e48 3230 if (rc != FAIL || LOGGING(sender_verify_fail))
278c6e6c
PH
3231 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
3232 host_and_ident(TRUE),
3233 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
3234 sender_verified_failed->address,
3235 (sender_verified_failed->message == NULL)? US"" :
3236 string_sprintf(": %s", sender_verified_failed->message));
059ec3d9 3237
02b41d71 3238 if (rc == FAIL && sender_verified_failed->user_message)
a5bd321b 3239 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
059ec3d9
PH
3240 testflag(sender_verified_failed, af_verify_pmfail)?
3241 "Postmaster verification failed while checking <%s>\n%s\n"
3242 "Several RFCs state that you are required to have a postmaster\n"
3243 "mailbox for each mail domain. This host does not accept mail\n"
3244 "from domains whose servers reject the postmaster address."
3245 :
3246 testflag(sender_verified_failed, af_verify_nsfail)?
3247 "Callback setup failed while verifying <%s>\n%s\n"
3248 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
3249 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
3250 "RFC requirements, and stops you from receiving standard bounce\n"
3251 "messages. This host does not accept mail from domains whose servers\n"
3252 "refuse bounces."
3253 :
3254 "Verification failed for <%s>\n%s",
3255 sender_verified_failed->address,
3256 sender_verified_failed->user_message));
2679d413
PH
3257
3258 rcpt_in_progress = save_rcpt_in_progress;
059ec3d9
PH
3259 }
3260
3261/* Sort out text for logging */
3262
3cc3f762
JH
3263log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
3264if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
059ec3d9
PH
3265
3266/* Send permanent failure response to the command, but the code used isn't
3267always a 5xx one - see comments at the start of this function. If the original
3268rc was FAIL_DROP we drop the connection and yield 2. */
3269
ff5929e3
JH
3270if (rc == FAIL)
3271 smtp_respond(smtp_code, codelen, TRUE,
3272 user_msg ? user_msg : US"Administrative prohibition");
059ec3d9
PH
3273
3274/* Send temporary failure response to the command. Don't give any details,
3275unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
3276verb, and for a header verify when smtp_return_error_details is set.
3277
3278This conditional logic is all somewhat of a mess because of the odd
3279interactions between temp_details and return_error_details. One day it should
3280be re-implemented in a tidier fashion. */
3281
3282else
ff5929e3 3283 if (acl_temp_details && user_msg)
059ec3d9 3284 {
ff5929e3
JH
3285 if ( smtp_return_error_details
3286 && sender_verified_failed
3287 && sender_verified_failed->message
3288 )
a5bd321b 3289 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
ff5929e3 3290
a5bd321b 3291 smtp_respond(smtp_code, codelen, TRUE, user_msg);
059ec3d9
PH
3292 }
3293 else
a5bd321b
PH
3294 smtp_respond(smtp_code, codelen, TRUE,
3295 US"Temporary local problem - please try later");
059ec3d9 3296
6ea85e9a
PH
3297/* Log the incident to the logs that are specified by log_reject_target
3298(default main, reject). This can be empty to suppress logging of rejections. If
3299the connection is not forcibly to be dropped, return 0. Otherwise, log why it
3300is closing if required and return 2. */
059ec3d9 3301
6ea85e9a 3302if (log_reject_target != 0)
887291d2 3303 {
e45a1c37 3304#ifdef SUPPORT_TLS
acec9514
JH
3305 gstring * g = s_tlslog(NULL);
3306 uschar * tls = string_from_gstring(g);
fc16abb4 3307 if (!tls) tls = US"";
e45a1c37 3308#else
fc16abb4 3309 uschar * tls = US"";
e45a1c37 3310#endif
3cc3f762
JH
3311 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
3312 log_reject_target, "%s%s%s %s%srejected %s%s",
fc16abb4
JH
3313 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
3314 host_and_ident(TRUE),
3315 tls,
3316 sender_info,
3317 rc == FAIL ? US"" : US"temporarily ",
3318 what, log_msg);
887291d2 3319 }
059ec3d9
PH
3320
3321if (!drop) return 0;
3322
3323log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3324 smtp_get_connection_info());
8f128379
PH
3325
3326/* Run the not-quit ACL, but without any custom messages. This should not be a
3327problem, because we get here only if some other ACL has issued "drop", and
3328in that case, *its* custom messages will have been used above. */
3329
3330smtp_notquit_exit(US"acl-drop", NULL, NULL);
059ec3d9
PH
3331return 2;
3332}
3333
3334
3335
3336
3337/*************************************************
8f128379
PH
3338* Handle SMTP exit when QUIT is not given *
3339*************************************************/
3340
3341/* This function provides a logging/statistics hook for when an SMTP connection
3342is dropped on the floor or the other end goes away. It's a global function
3343because it's called from receive.c as well as this module. As well as running
3344the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3345response, either with a custom message from the ACL, or using a default. There
3346is one case, however, when no message is output - after "drop". In that case,
3347the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3348passed to this function.
3349
3350In case things go wrong while processing this function, causing an error that
4c04137d 3351may re-enter this function, there is a recursion check.
8f128379
PH
3352
3353Arguments:
3354 reason What $smtp_notquit_reason will be set to in the ACL;
3355 if NULL, the ACL is not run
3356 code The error code to return as part of the response
3357 defaultrespond The default message if there's no user_msg
3358
3359Returns: Nothing
3360*/
3361
3362void
3363smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3364{
3365int rc;
3366uschar *user_msg = NULL;
3367uschar *log_msg = NULL;
3368
3369/* Check for recursive acll */
3370
3371if (smtp_exit_function_called)
3372 {
3373 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3374 reason);
3375 return;
3376 }
3377smtp_exit_function_called = TRUE;
3378
3379/* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3380
eea0defe 3381if (acl_smtp_notquit && reason)
8f128379
PH
3382 {
3383 smtp_notquit_reason = reason;
eea0defe
JB
3384 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3385 &log_msg)) == ERROR)
8f128379
PH
3386 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3387 log_msg);
3388 }
3389
3390/* Write an SMTP response if we are expected to give one. As the default
3391responses are all internal, they should always fit in the buffer, but code a
3392warning, just in case. Note that string_vformat() still leaves a complete
3393string, even if it is incomplete. */
3394
eea0defe 3395if (code && defaultrespond)
8f128379 3396 {
eea0defe
JB
3397 if (user_msg)
3398 smtp_respond(code, 3, TRUE, user_msg);
3399 else
8f128379
PH
3400 {
3401 uschar buffer[128];
3402 va_list ap;
3403 va_start(ap, defaultrespond);
3404 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3405 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
925ac8e4 3406 smtp_printf("%s %s\r\n", FALSE, code, buffer);
8f128379
PH
3407 va_end(ap);
3408 }
8f128379
PH
3409 mac_smtp_fflush();
3410 }
3411}
3412
3413
3414
3415
3416/*************************************************
d7b47fd0
PH
3417* Verify HELO argument *
3418*************************************************/
3419
3420/* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3421matched. It is also called from ACL processing if verify = helo is used and
3422verification was not previously tried (i.e. helo_try_verify_hosts was not
3423matched). The result of its processing is to set helo_verified and
3424helo_verify_failed. These variables should both be FALSE for this function to
3425be called.
3426
3427Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3428for IPv6 ::ffff: literals.
3429
3430Argument: none
3431Returns: TRUE if testing was completed;
3432 FALSE on a temporary failure
3433*/
3434
3435BOOL
3436smtp_verify_helo(void)
3437{
3438BOOL yield = TRUE;
3439
3440HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3441 sender_helo_name);
3442
3443if (sender_helo_name == NULL)
3444 {
3445 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3446 }
3447
d1d5595c
PH
3448/* Deal with the case of -bs without an IP address */
3449
3450else if (sender_host_address == NULL)
3451 {
3452 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3453 helo_verified = TRUE;
3454 }
3455
3456/* Deal with the more common case when there is a sending IP address */
3457
d7b47fd0
PH
3458else if (sender_helo_name[0] == '[')
3459 {
3460 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3461 Ustrlen(sender_host_address)) == 0;
3462
3463 #if HAVE_IPV6
3464 if (!helo_verified)
3465 {
3466 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3467 helo_verified = Ustrncmp(sender_helo_name + 1,
3468 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3469 }
3470 #endif
3471
3472 HDEBUG(D_receive)
3473 { if (helo_verified) debug_printf("matched host address\n"); }
3474 }
3475
3476/* Do a reverse lookup if one hasn't already given a positive or negative
3477response. If that fails, or the name doesn't match, try checking with a forward
3478lookup. */
3479
3480else
3481 {
3482 if (sender_host_name == NULL && !host_lookup_failed)
3483 yield = host_name_lookup() != DEFER;
3484
3485 /* If a host name is known, check it and all its aliases. */
3486
1705dd20
JH
3487 if (sender_host_name)
3488 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
d7b47fd0 3489 {
1705dd20 3490 sender_helo_dnssec = sender_host_dnssec;
d7b47fd0
PH
3491 HDEBUG(D_receive) debug_printf("matched host name\n");
3492 }
3493 else
3494 {
3495 uschar **aliases = sender_host_aliases;
1705dd20
JH
3496 while (*aliases)
3497 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3498 {
3499 sender_helo_dnssec = sender_host_dnssec;
3500 break;
3501 }
3502
3503 HDEBUG(D_receive) if (helo_verified)
d7b47fd0 3504 debug_printf("matched alias %s\n", *(--aliases));
d7b47fd0 3505 }
d7b47fd0
PH
3506
3507 /* Final attempt: try a forward lookup of the helo name */
3508
3509 if (!helo_verified)
3510 {
3511 int rc;
3512 host_item h;
1705dd20
JH
3513 dnssec_domains d;
3514 host_item *hh;
3515
d7b47fd0
PH
3516 h.name = sender_helo_name;
3517 h.address = NULL;
3518 h.mx = MX_NONE;
3519 h.next = NULL;
1705dd20
JH
3520 d.request = US"*";
3521 d.require = US"";
3522
d7b47fd0
PH
3523 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3524 sender_helo_name);
66387a73 3525 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
1705dd20 3526 NULL, NULL, NULL, &d, NULL, NULL);
d7b47fd0 3527 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
1705dd20 3528 for (hh = &h; hh; hh = hh->next)
d7b47fd0
PH
3529 if (Ustrcmp(hh->address, sender_host_address) == 0)
3530 {
3531 helo_verified = TRUE;
1705dd20 3532 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
d7b47fd0 3533 HDEBUG(D_receive)
1705dd20
JH
3534 {
3535 debug_printf("IP address for %s matches calling address\n"
3536 "Forward DNS security status: %sverified\n",
3537 sender_helo_name, sender_helo_dnssec ? "" : "un");
3538 }
d7b47fd0
PH
3539 break;
3540 }
d7b47fd0
PH
3541 }
3542 }
3543
d1d5595c 3544if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
d7b47fd0
PH
3545return yield;
3546}
3547
3548
3549
3550
3551/*************************************************
4e88a19f
PH
3552* Send user response message *
3553*************************************************/
3554
3555/* This function is passed a default response code and a user message. It calls
3556smtp_message_code() to check and possibly modify the response code, and then
3557calls smtp_respond() to transmit the response. I put this into a function
3558just to avoid a lot of repetition.
3559
3560Arguments:
3561 code the response code
3562 user_msg the user message
3563
3564Returns: nothing
3565*/
3566
3567static void
3568smtp_user_msg(uschar *code, uschar *user_msg)
3569{
3570int len = 3;
4f6ae5c3 3571smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
4e88a19f
PH
3572smtp_respond(code, len, TRUE, user_msg);
3573}
3574
3575
3576
b3ef41c9
JH
3577static int
3578smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3579{
3580const uschar *set_id = NULL;
3581int rc, i;
3582
3583/* Run the checking code, passing the remainder of the command line as
3584data. Initials the $auth<n> variables as empty. Initialize $0 empty and set