1 /* $NetBSD: cleanup_api.c,v 1.4 2022/10/08 16:12:45 christos Exp $ */
2
3 /*++
4 /* NAME
5 /* cleanup_api 3
6 /* SUMMARY
7 /* cleanup callable interface, message processing
8 /* SYNOPSIS
9 /* #include "cleanup.h"
10 /*
11 /* CLEANUP_STATE *cleanup_open(src)
12 /* VSTREAM *src;
13 /*
14 /* void cleanup_control(state, flags)
15 /* CLEANUP_STATE *state;
16 /* int flags;
17 /*
18 /* void CLEANUP_RECORD(state, type, buf, len)
19 /* CLEANUP_STATE *state;
20 /* int type;
21 /* char *buf;
22 /* int len;
23 /*
24 /* int cleanup_flush(state)
25 /* CLEANUP_STATE *state;
26 /*
27 /* int cleanup_free(state)
28 /* CLEANUP_STATE *state;
29 /* DESCRIPTION
30 /* This module implements a callable interface to the cleanup service
31 /* for processing one message and for writing it to queue file.
32 /* For a description of the cleanup service, see cleanup(8).
33 /*
34 /* cleanup_open() creates a new queue file and performs other
35 /* per-message initialization. The result is a handle that should be
36 /* given to the cleanup_control(), cleanup_record(), cleanup_flush()
37 /* and cleanup_free() routines. The name of the queue file is in the
38 /* queue_id result structure member.
39 /*
40 /* cleanup_control() processes per-message flags specified by the caller.
41 /* These flags control the handling of data errors, and must be set
42 /* before processing the first message record.
43 /* .IP CLEANUP_FLAG_BOUNCE
44 /* The cleanup server is responsible for returning undeliverable
45 /* mail (too many hops, message too large) to the sender.
46 /* .IP CLEANUP_FLAG_BCC_OK
47 /* It is OK to add automatic BCC recipient addresses.
48 /* .IP CLEANUP_FLAG_FILTER
49 /* Enable header/body filtering. This should be enabled only with mail
50 /* that enters Postfix, not with locally forwarded mail or with bounce
51 /* messages.
52 /* .IP CLEANUP_FLAG_MILTER
53 /* Enable Milter applications. This should be enabled only with mail
54 /* that enters Postfix, not with locally forwarded mail or with bounce
55 /* messages.
56 /* .IP CLEANUP_FLAG_MAP_OK
57 /* Enable canonical and virtual mapping, and address masquerading.
58 /* .PP
59 /* For convenience the CLEANUP_FLAG_MASK_EXTERNAL macro specifies
60 /* the options that are normally needed for mail that enters
61 /* Postfix from outside, and CLEANUP_FLAG_MASK_INTERNAL specifies
62 /* the options that are normally needed for internally generated or
63 /* forwarded mail.
64 /*
65 /* CLEANUP_RECORD() is a macro that processes one message record,
66 /* that copies the result to the queue file, and that maintains a
67 /* little state machine. The last record in a valid message has type
68 /* REC_TYPE_END. In order to find out if a message is corrupted,
69 /* the caller is encouraged to test the CLEANUP_OUT_OK(state) macro.
70 /* The result is false when further message processing is futile.
71 /* In that case, it is safe to call cleanup_flush() immediately.
72 /*
73 /* cleanup_flush() closes a queue file. In case of any errors,
74 /* the file is removed. The result value is non-zero in case of
75 /* problems. In some cases a human-readable text can be found in
76 /* the state->reason member. In all other cases, use cleanup_strerror()
77 /* to translate the result into human-readable text.
78 /*
79 /* cleanup_free() destroys its argument.
80 /* .IP CLEANUP_FLAG_SMTPUTF8
81 /* Request SMTPUTF8 support when delivering mail.
82 /* .IP CLEANUP_FLAG_AUTOUTF8
83 /* Autodetection: request SMTPUTF8 support if the message
84 /* contains an UTF8 message header, sender, or recipient.
85 /* DIAGNOSTICS
86 /* Problems and transactions are logged to \fBsyslogd\fR(8)
87 /* or \fBpostlogd\fR(8).
88 /* SEE ALSO
89 /* cleanup(8) cleanup service description.
90 /* cleanup_init(8) cleanup callable interface, initialization
91 /* LICENSE
92 /* .ad
93 /* .fi
94 /* The Secure Mailer license must be distributed with this software.
95 /* AUTHOR(S)
96 /* Wietse Venema
97 /* IBM T.J. Watson Research
98 /* P.O. Box 704
99 /* Yorktown Heights, NY 10598, USA
100 /*
101 /* Wietse Venema
102 /* Google, Inc.
103 /* 111 8th Avenue
104 /* New York, NY 10011, USA
105 /*--*/
106
107 /* System library. */
108
109 #include <sys_defs.h>
110 #include <errno.h>
111
112 /* Utility library. */
113
114 #include <msg.h>
115 #include <vstring.h>
116 #include <mymalloc.h>
117
118 /* Global library. */
119
120 #include <cleanup_user.h>
121 #include <mail_queue.h>
122 #include <mail_proto.h>
123 #include <bounce.h>
124 #include <mail_params.h>
125 #include <mail_stream.h>
126 #include <mail_flow.h>
127 #include <rec_type.h>
128 #include <smtputf8.h>
129
130 /* Milter library. */
131
132 #include <milter.h>
133
134 /* Application-specific. */
135
136 #include "cleanup.h"
137
138 /* cleanup_open - open queue file and initialize */
139
cleanup_open(VSTREAM * src)140 CLEANUP_STATE *cleanup_open(VSTREAM *src)
141 {
142 CLEANUP_STATE *state;
143 static const char *log_queues[] = {
144 MAIL_QUEUE_DEFER,
145 MAIL_QUEUE_BOUNCE,
146 MAIL_QUEUE_TRACE,
147 0,
148 };
149 const char **cpp;
150
151 /*
152 * Initialize private state.
153 */
154 state = cleanup_state_alloc(src);
155
156 /*
157 * Open the queue file. Save the queue file name in a global variable, so
158 * that the runtime error handler can clean up in case of problems.
159 *
160 * XXX For now, a lot of detail is frozen that could be more useful if it
161 * were made configurable.
162 */
163 state->queue_name = mystrdup(MAIL_QUEUE_INCOMING);
164 state->handle = mail_stream_file(state->queue_name,
165 MAIL_CLASS_PUBLIC, var_queue_service, 0);
166 state->dst = state->handle->stream;
167 cleanup_path = mystrdup(VSTREAM_PATH(state->dst));
168 state->queue_id = mystrdup(state->handle->id);
169 if (msg_verbose)
170 msg_info("cleanup_open: open %s", cleanup_path);
171
172 /*
173 * If there is a time to get rid of spurious log files, this is it. The
174 * down side is that this costs performance for every message, while the
175 * probability of spurious log files is quite low.
176 *
177 * XXX The defer logfile is deleted when the message is moved into the
178 * active queue. We must also remove it now, otherwise mailq produces
179 * nonsense.
180 */
181 for (cpp = log_queues; *cpp; cpp++) {
182 if (mail_queue_remove(*cpp, state->queue_id) == 0)
183 msg_warn("%s: removed spurious %s log", *cpp, state->queue_id);
184 else if (errno != ENOENT)
185 msg_fatal("%s: remove %s log: %m", *cpp, state->queue_id);
186 }
187 return (state);
188 }
189
190 /* cleanup_control - process client options */
191
cleanup_control(CLEANUP_STATE * state,int flags)192 void cleanup_control(CLEANUP_STATE *state, int flags)
193 {
194
195 /*
196 * If the client requests us to do the bouncing in case of problems,
197 * throw away the input only in case of real show-stopper errors, such as
198 * unrecognizable data (which should never happen) or insufficient space
199 * for the queue file (which will happen occasionally). Otherwise,
200 * discard input after any lethal error. See the CLEANUP_OUT_OK() macro
201 * definition.
202 */
203 if (msg_verbose)
204 msg_info("cleanup flags = %s", cleanup_strflags(flags));
205 if ((state->flags = flags) & CLEANUP_FLAG_BOUNCE) {
206 state->err_mask = CLEANUP_STAT_MASK_INCOMPLETE;
207 } else {
208 state->err_mask = ~0;
209 }
210 if (state->flags & CLEANUP_FLAG_SMTPUTF8)
211 state->smtputf8 = SMTPUTF8_FLAG_REQUESTED;
212 }
213
214 /* cleanup_flush - finish queue file */
215
cleanup_flush(CLEANUP_STATE * state)216 int cleanup_flush(CLEANUP_STATE *state)
217 {
218 int status;
219 char *junk;
220 VSTRING *trace_junk;
221
222 /*
223 * Raise these errors only if we examined all queue file records.
224 */
225 if (CLEANUP_OUT_OK(state)) {
226 if (state->recip == 0)
227 state->errs |= CLEANUP_STAT_RCPT;
228 if ((state->flags & CLEANUP_FLAG_END_SEEN) == 0)
229 state->errs |= CLEANUP_STAT_BAD;
230 }
231
232 /*
233 * Status sanitization. Always report success when the discard flag was
234 * raised by some user-specified access rule.
235 */
236 if (state->flags & CLEANUP_FLAG_DISCARD)
237 state->errs = 0;
238
239 /*
240 * Apply external mail filter.
241 *
242 * XXX Include test for a built-in action to tempfail this message.
243 */
244 if (CLEANUP_MILTER_OK(state)) {
245 if (state->milters)
246 cleanup_milter_inspect(state, state->milters);
247 else if (cleanup_milters) {
248 cleanup_milter_emul_data(state, cleanup_milters);
249 if (CLEANUP_MILTER_OK(state))
250 cleanup_milter_inspect(state, cleanup_milters);
251 }
252 }
253
254 /*
255 * Update the preliminary message size and count fields with the actual
256 * values.
257 */
258 if (CLEANUP_OUT_OK(state))
259 cleanup_final(state);
260
261 /*
262 * If there was an error that requires us to generate a bounce message
263 * (mail submitted with the Postfix sendmail command, mail forwarded by
264 * the local(8) delivery agent, or mail re-queued with "postsuper -r"),
265 * send a bounce notification, reset the error flags in case of success,
266 * and request deletion of the incoming queue file and of the
267 * optional DSN SUCCESS records from virtual alias expansion.
268 *
269 * XXX It would make no sense to knowingly report success after we already
270 * have bounced all recipients, especially because the information in the
271 * DSN SUCCESS notice is completely redundant compared to the information
272 * in the bounce notice (however, both may be incomplete when the queue
273 * file size would exceed the safety limit).
274 *
275 * An alternative is to keep the DSN SUCCESS records and to delegate bounce
276 * notification to the queue manager, just like we already delegate
277 * success notification. This requires that we leave the undeliverable
278 * message in the incoming queue; versions up to 20050726 did exactly
279 * that. Unfortunately, this broke with over-size queue files, because
280 * the queue manager cannot handle incomplete queue files (and it should
281 * not try to do so).
282 */
283 #define CAN_BOUNCE() \
284 ((state->errs & CLEANUP_STAT_MASK_CANT_BOUNCE) == 0 \
285 && state->sender != 0 \
286 && (state->flags & CLEANUP_FLAG_BOUNCE) != 0)
287
288 if (state->errs != 0 && CAN_BOUNCE())
289 cleanup_bounce(state);
290
291 /*
292 * Optionally, place the message on hold, but only if the message was
293 * received successfully and only if it's not being discarded for other
294 * reasons. This involves renaming the queue file before "finishing" it
295 * (or else the queue manager would grab it too early) and updating our
296 * own idea of the queue file name for error recovery and for error
297 * reporting purposes.
298 *
299 * XXX Include test for a built-in action to tempfail this message.
300 */
301 if (state->errs == 0 && (state->flags & CLEANUP_FLAG_DISCARD) == 0) {
302 if ((state->flags & CLEANUP_FLAG_HOLD) != 0
303 #ifdef DELAY_ACTION
304 || state->defer_delay > 0
305 #endif
306 ) {
307 myfree(state->queue_name);
308 #ifdef DELAY_ACTION
309 state->queue_name = mystrdup((state->flags & CLEANUP_FLAG_HOLD) ?
310 MAIL_QUEUE_HOLD : MAIL_QUEUE_DEFERRED);
311 #else
312 state->queue_name = mystrdup(MAIL_QUEUE_HOLD);
313 #endif
314 mail_stream_ctl(state->handle,
315 CA_MAIL_STREAM_CTL_QUEUE(state->queue_name),
316 CA_MAIL_STREAM_CTL_CLASS((char *) 0),
317 CA_MAIL_STREAM_CTL_SERVICE((char *) 0),
318 #ifdef DELAY_ACTION
319 CA_MAIL_STREAM_CTL_DELAY(state->defer_delay),
320 #endif
321 CA_MAIL_STREAM_CTL_END);
322 junk = cleanup_path;
323 cleanup_path = mystrdup(VSTREAM_PATH(state->handle->stream));
324 myfree(junk);
325
326 /*
327 * XXX: When delivering to a non-incoming queue, do not consume
328 * in_flow tokens. Unfortunately we can't move the code that
329 * consumes tokens until after the mail is received, because that
330 * would increase the risk of duplicate deliveries (RFC 1047).
331 */
332 (void) mail_flow_put(1);
333 }
334 state->errs = mail_stream_finish(state->handle, (VSTRING *) 0);
335 } else {
336
337 /*
338 * XXX: When discarding mail, should we consume in_flow tokens? See
339 * also the comments above for mail that is placed on hold.
340 */
341 #if 0
342 (void) mail_flow_put(1);
343 #endif
344 mail_stream_cleanup(state->handle);
345 }
346 state->handle = 0;
347 state->dst = 0;
348
349 /*
350 * If there was an error, or if the message must be discarded for other
351 * reasons, remove the queue file and the optional trace file with DSN
352 * SUCCESS records from virtual alias expansion.
353 */
354 if (state->errs != 0 || (state->flags & CLEANUP_FLAG_DISCARD) != 0) {
355 if (cleanup_trace_path)
356 (void) REMOVE(vstring_str(cleanup_trace_path));
357 if (REMOVE(cleanup_path))
358 msg_warn("remove %s: %m", cleanup_path);
359 }
360
361 /*
362 * Make sure that our queue file will not be deleted by the error handler
363 * AFTER we have taken responsibility for delivery. Better to deliver
364 * twice than to lose mail.
365 */
366 trace_junk = cleanup_trace_path;
367 cleanup_trace_path = 0; /* don't delete upon error */
368 junk = cleanup_path;
369 cleanup_path = 0; /* don't delete upon error */
370
371 if (trace_junk)
372 vstring_free(trace_junk);
373 myfree(junk);
374
375 /*
376 * Cleanup internal state. This is simply complementary to the
377 * initializations at the beginning of cleanup_open().
378 */
379 if (msg_verbose)
380 msg_info("cleanup_flush: status %d", state->errs);
381 status = state->errs;
382 return (status);
383 }
384
385 /* cleanup_free - pay the last respects */
386
cleanup_free(CLEANUP_STATE * state)387 void cleanup_free(CLEANUP_STATE *state)
388 {
389
390 /*
391 * Emulate disconnect event. CLEANUP_FLAG_MILTER may be turned off after
392 * we have started.
393 */
394 if (cleanup_milters != 0 && state->milters == 0)
395 milter_disc_event(cleanup_milters);
396 cleanup_state_free(state);
397 }
398