1 /*
2  * Copyright (c) 1983 Eric P. Allman
3  * Copyright (c) 1988, 1993
4  *	The Regents of the University of California.  All rights reserved.
5  *
6  * %sccs.include.redist.c%
7  */
8 
9 #ifndef lint
10 static char sccsid[] = "@(#)savemail.c	8.5 (Berkeley) 07/17/93";
11 #endif /* not lint */
12 
13 # include <pwd.h>
14 # include "sendmail.h"
15 
16 /*
17 **  SAVEMAIL -- Save mail on error
18 **
19 **	If mailing back errors, mail it back to the originator
20 **	together with an error message; otherwise, just put it in
21 **	dead.letter in the user's home directory (if he exists on
22 **	this machine).
23 **
24 **	Parameters:
25 **		e -- the envelope containing the message in error.
26 **
27 **	Returns:
28 **		none
29 **
30 **	Side Effects:
31 **		Saves the letter, by writing or mailing it back to the
32 **		sender, or by putting it in dead.letter in her home
33 **		directory.
34 */
35 
36 /* defines for state machine */
37 # define ESM_REPORT	0	/* report to sender's terminal */
38 # define ESM_MAIL	1	/* mail back to sender */
39 # define ESM_QUIET	2	/* messages have already been returned */
40 # define ESM_DEADLETTER	3	/* save in ~/dead.letter */
41 # define ESM_POSTMASTER	4	/* return to postmaster */
42 # define ESM_USRTMP	5	/* save in /usr/tmp/dead.letter */
43 # define ESM_PANIC	6	/* leave the locked queue/transcript files */
44 # define ESM_DONE	7	/* the message is successfully delivered */
45 
46 
47 savemail(e)
48 	register ENVELOPE *e;
49 {
50 	register struct passwd *pw;
51 	register FILE *fp;
52 	int state;
53 	auto ADDRESS *q = NULL;
54 	char buf[MAXLINE+1];
55 	extern struct passwd *getpwnam();
56 	register char *p;
57 	extern char *ttypath();
58 	typedef int (*fnptr)();
59 
60 	if (tTd(6, 1))
61 	{
62 		printf("\nsavemail, errormode = %c, id = %s\n  e_from=",
63 			e->e_errormode, e->e_id == NULL ? "NONE" : e->e_id);
64 		printaddr(&e->e_from, FALSE);
65 	}
66 
67 	if (e->e_id == NULL)
68 	{
69 		/* can't return a message with no id */
70 		return;
71 	}
72 
73 	e->e_flags &= ~EF_FATALERRS;
74 
75 	/*
76 	**  In the unhappy event we don't know who to return the mail
77 	**  to, make someone up.
78 	*/
79 
80 	if (e->e_from.q_paddr == NULL)
81 	{
82 		e->e_sender = "Postmaster";
83 		if (parseaddr(e->e_sender, &e->e_from, 0, '\0', NULL, e) == NULL)
84 		{
85 			syserr("553 Cannot parse Postmaster!");
86 			ExitStat = EX_SOFTWARE;
87 			finis();
88 		}
89 	}
90 	e->e_to = NULL;
91 
92 	/*
93 	**  Basic state machine.
94 	**
95 	**	This machine runs through the following states:
96 	**
97 	**	ESM_QUIET	Errors have already been printed iff the
98 	**			sender is local.
99 	**	ESM_REPORT	Report directly to the sender's terminal.
100 	**	ESM_MAIL	Mail response to the sender.
101 	**	ESM_DEADLETTER	Save response in ~/dead.letter.
102 	**	ESM_POSTMASTER	Mail response to the postmaster.
103 	**	ESM_PANIC	Save response anywhere possible.
104 	*/
105 
106 	/* determine starting state */
107 	switch (e->e_errormode)
108 	{
109 	  case EM_WRITE:
110 		state = ESM_REPORT;
111 		break;
112 
113 	  case EM_BERKNET:
114 		/* mail back, but return o.k. exit status */
115 		ExitStat = EX_OK;
116 
117 		/* fall through.... */
118 
119 	  case EM_MAIL:
120 		state = ESM_MAIL;
121 		break;
122 
123 	  case EM_PRINT:
124 	  case '\0':
125 		state = ESM_QUIET;
126 		break;
127 
128 	  case EM_QUIET:
129 		/* no need to return anything at all */
130 		return;
131 
132 	  default:
133 		syserr("554 savemail: bogus errormode x%x\n", e->e_errormode);
134 		state = ESM_MAIL;
135 		break;
136 	}
137 
138 	/* if this is already an error response, send to postmaster */
139 	if (bitset(EF_RESPONSE, e->e_flags))
140 	{
141 		if (e->e_parent != NULL &&
142 		    bitset(EF_RESPONSE, e->e_parent->e_flags))
143 		{
144 			/* got an error sending a response -- can it */
145 			return;
146 		}
147 		state = ESM_POSTMASTER;
148 	}
149 
150 	while (state != ESM_DONE)
151 	{
152 		if (tTd(6, 5))
153 			printf("  state %d\n", state);
154 
155 		switch (state)
156 		{
157 		  case ESM_QUIET:
158 			if (e->e_from.q_mailer == LocalMailer)
159 				state = ESM_DEADLETTER;
160 			else
161 				state = ESM_MAIL;
162 			break;
163 
164 		  case ESM_REPORT:
165 
166 			/*
167 			**  If the user is still logged in on the same terminal,
168 			**  then write the error messages back to hir (sic).
169 			*/
170 
171 			p = ttypath();
172 			if (p == NULL || freopen(p, "w", stdout) == NULL)
173 			{
174 				state = ESM_MAIL;
175 				break;
176 			}
177 
178 			expand("\201n", buf, &buf[sizeof buf - 1], e);
179 			printf("\r\nMessage from %s...\r\n", buf);
180 			printf("Errors occurred while sending mail.\r\n");
181 			if (e->e_xfp != NULL)
182 			{
183 				(void) fflush(e->e_xfp);
184 				fp = fopen(queuename(e, 'x'), "r");
185 			}
186 			else
187 				fp = NULL;
188 			if (fp == NULL)
189 			{
190 				syserr("Cannot open %s", queuename(e, 'x'));
191 				printf("Transcript of session is unavailable.\r\n");
192 			}
193 			else
194 			{
195 				printf("Transcript follows:\r\n");
196 				while (fgets(buf, sizeof buf, fp) != NULL &&
197 				       !ferror(stdout))
198 					fputs(buf, stdout);
199 				(void) xfclose(fp, "savemail transcript", e->e_id);
200 			}
201 			printf("Original message will be saved in dead.letter.\r\n");
202 			state = ESM_DEADLETTER;
203 			break;
204 
205 		  case ESM_MAIL:
206 			/*
207 			**  If mailing back, do it.
208 			**	Throw away all further output.  Don't alias,
209 			**	since this could cause loops, e.g., if joe
210 			**	mails to joe@x, and for some reason the network
211 			**	for @x is down, then the response gets sent to
212 			**	joe@x, which gives a response, etc.  Also force
213 			**	the mail to be delivered even if a version of
214 			**	it has already been sent to the sender.
215 			**
216 			**  If this is a configuration or local software
217 			**	error, send to the local postmaster as well,
218 			**	since the originator can't do anything
219 			**	about it anyway.  Note that this is a full
220 			**	copy of the message (intentionally) so that
221 			**	the Postmaster can forward things along.
222 			*/
223 
224 			if (ExitStat == EX_CONFIG || ExitStat == EX_SOFTWARE)
225 			{
226 				(void) sendtolist("postmaster",
227 					  (ADDRESS *) NULL,
228 					  &e->e_errorqueue, e);
229 			}
230 			if (strcmp(e->e_from.q_paddr, "<>") != 0)
231 			{
232 				(void) sendtolist(e->e_from.q_paddr,
233 					  (ADDRESS *) NULL,
234 					  &e->e_errorqueue, e);
235 			}
236 
237 			/*
238 			**  Deliver a non-delivery report to the
239 			**  Postmaster-designate (not necessarily
240 			**  Postmaster).  This does not include the
241 			**  body of the message, for privacy reasons.
242 			**  You really shouldn't need this.
243 			*/
244 
245 			e->e_flags |= EF_PM_NOTIFY;
246 
247 			q = e->e_errorqueue;
248 			if (q == NULL)
249 			{
250 				/* this is an error-error */
251 				state = ESM_POSTMASTER;
252 				break;
253 			}
254 			if (returntosender(e->e_message,
255 					   q, (e->e_class >= 0), e) == 0)
256 			{
257 				state = ESM_DONE;
258 				break;
259 			}
260 
261 			/* didn't work -- return to postmaster */
262 			state = ESM_POSTMASTER;
263 			break;
264 
265 		  case ESM_POSTMASTER:
266 			/*
267 			**  Similar to previous case, but to system postmaster.
268 			*/
269 
270 			q = NULL;
271 			if (sendtolist("postmaster", NULL, &q, e) <= 0)
272 			{
273 				syserr("553 cannot parse postmaster!");
274 				ExitStat = EX_SOFTWARE;
275 				state = ESM_USRTMP;
276 				break;
277 			}
278 			if (returntosender(e->e_message,
279 					   q, (e->e_class >= 0), e) == 0)
280 			{
281 				state = ESM_DONE;
282 				break;
283 			}
284 
285 			/* didn't work -- last resort */
286 			state = ESM_USRTMP;
287 			break;
288 
289 		  case ESM_DEADLETTER:
290 			/*
291 			**  Save the message in dead.letter.
292 			**	If we weren't mailing back, and the user is
293 			**	local, we should save the message in
294 			**	~/dead.letter so that the poor person doesn't
295 			**	have to type it over again -- and we all know
296 			**	what poor typists UNIX users are.
297 			*/
298 
299 			p = NULL;
300 			if (e->e_from.q_mailer == LocalMailer)
301 			{
302 				if (e->e_from.q_home != NULL)
303 					p = e->e_from.q_home;
304 				else if ((pw = getpwnam(e->e_from.q_user)) != NULL)
305 					p = pw->pw_dir;
306 			}
307 			if (p == NULL)
308 			{
309 				/* no local directory */
310 				state = ESM_MAIL;
311 				break;
312 			}
313 			if (e->e_dfp != NULL)
314 			{
315 				bool oldverb = Verbose;
316 
317 				/* we have a home directory; open dead.letter */
318 				define('z', p, e);
319 				expand("\201z/dead.letter", buf, &buf[sizeof buf - 1], e);
320 				Verbose = TRUE;
321 				message("Saving message in %s", buf);
322 				Verbose = oldverb;
323 				e->e_to = buf;
324 				q = NULL;
325 				(void) sendtolist(buf, &e->e_from, &q, e);
326 				if (deliver(e, q) == 0)
327 					state = ESM_DONE;
328 				else
329 					state = ESM_MAIL;
330 			}
331 			else
332 			{
333 				/* no data file -- try mailing back */
334 				state = ESM_MAIL;
335 			}
336 			break;
337 
338 		  case ESM_USRTMP:
339 			/*
340 			**  Log the mail in /usr/tmp/dead.letter.
341 			*/
342 
343 			if (e->e_class < 0)
344 			{
345 				state = ESM_DONE;
346 				break;
347 			}
348 
349 			fp = dfopen("/usr/tmp/dead.letter",
350 				    O_WRONLY|O_CREAT|O_APPEND, FileMode);
351 			if (fp == NULL)
352 			{
353 				state = ESM_PANIC;
354 				break;
355 			}
356 
357 			putfromline(fp, FileMailer, e);
358 			(*e->e_puthdr)(fp, FileMailer, e);
359 			putline("\n", fp, FileMailer);
360 			(*e->e_putbody)(fp, FileMailer, e, NULL);
361 			putline("\n", fp, FileMailer);
362 			(void) fflush(fp);
363 			state = ferror(fp) ? ESM_PANIC : ESM_DONE;
364 			(void) xfclose(fp, "savemail", "/usr/tmp/dead.letter");
365 			break;
366 
367 		  default:
368 			syserr("554 savemail: unknown state %d", state);
369 
370 			/* fall through ... */
371 
372 		  case ESM_PANIC:
373 			/* leave the locked queue & transcript files around */
374 			syserr("554 savemail: cannot save rejected email anywhere");
375 			exit(EX_SOFTWARE);
376 		}
377 	}
378 }
379 /*
380 **  RETURNTOSENDER -- return a message to the sender with an error.
381 **
382 **	Parameters:
383 **		msg -- the explanatory message.
384 **		returnq -- the queue of people to send the message to.
385 **		sendbody -- if TRUE, also send back the body of the
386 **			message; otherwise just send the header.
387 **		e -- the current envelope.
388 **
389 **	Returns:
390 **		zero -- if everything went ok.
391 **		else -- some error.
392 **
393 **	Side Effects:
394 **		Returns the current message to the sender via
395 **		mail.
396 */
397 
398 static bool	SendBody;
399 
400 #define MAXRETURNS	6	/* max depth of returning messages */
401 #define ERRORFUDGE	100	/* nominal size of error message text */
402 
403 returntosender(msg, returnq, sendbody, e)
404 	char *msg;
405 	ADDRESS *returnq;
406 	bool sendbody;
407 	register ENVELOPE *e;
408 {
409 	char buf[MAXNAME];
410 	extern putheader(), errbody();
411 	register ENVELOPE *ee;
412 	ENVELOPE *oldcur = CurEnv;
413 	ENVELOPE errenvelope;
414 	static int returndepth;
415 	register ADDRESS *q;
416 
417 	if (returnq == NULL)
418 		return (-1);
419 
420 	if (msg == NULL)
421 		msg = "Unable to deliver mail";
422 
423 	if (tTd(6, 1))
424 	{
425 		printf("Return To Sender: msg=\"%s\", depth=%d, e=%x, returnq=",
426 		       msg, returndepth, e);
427 		printaddr(returnq, TRUE);
428 	}
429 
430 	if (++returndepth >= MAXRETURNS)
431 	{
432 		if (returndepth != MAXRETURNS)
433 			syserr("554 returntosender: infinite recursion on %s", returnq->q_paddr);
434 		/* don't "unrecurse" and fake a clean exit */
435 		/* returndepth--; */
436 		return (0);
437 	}
438 
439 	SendBody = sendbody;
440 	define('g', e->e_from.q_paddr, e);
441 	ee = newenvelope(&errenvelope, e);
442 	define('a', "\201b", ee);
443 	define('r', "internal", ee);
444 	define('s', "localhost", ee);
445 	define('_', "localhost", ee);
446 	ee->e_puthdr = putheader;
447 	ee->e_putbody = errbody;
448 	ee->e_flags |= EF_RESPONSE;
449 	if (!bitset(EF_OLDSTYLE, e->e_flags))
450 		ee->e_flags &= ~EF_OLDSTYLE;
451 	ee->e_sendqueue = returnq;
452 	ee->e_msgsize = e->e_msgsize + ERRORFUDGE;
453 	openxscript(ee);
454 	for (q = returnq; q != NULL; q = q->q_next)
455 	{
456 		if (bitset(QBADADDR, q->q_flags))
457 			continue;
458 
459 		if (!bitset(QDONTSEND, q->q_flags))
460 			ee->e_nrcpts++;
461 
462 		if (!DontPruneRoutes && pruneroute(q->q_paddr))
463 			parseaddr(q->q_paddr, q, 0, '\0', NULL, e);
464 
465 		if (q->q_alias == NULL)
466 			addheader("To", q->q_paddr, ee);
467 	}
468 
469 # ifdef LOG
470 	if (LogLevel > 5)
471 		syslog(LOG_INFO, "%s: %s: return to sender: %s",
472 			e->e_id, ee->e_id, msg);
473 # endif
474 
475 	(void) sprintf(buf, "Returned mail: %s", msg);
476 	addheader("Subject", buf, ee);
477 	if (SendMIMEErrors)
478 	{
479 		addheader("MIME-Version", "1.0", ee);
480 		(void) sprintf(buf, "%s.%ld/%s",
481 			ee->e_id, curtime(), MyHostName);
482 		ee->e_msgboundary = newstr(buf);
483 		(void) sprintf(buf, "multipart/mixed; boundary=\"%s\"",
484 					ee->e_msgboundary);
485 		addheader("Content-Type", buf, ee);
486 	}
487 
488 	/* fake up an address header for the from person */
489 	expand("\201n", buf, &buf[sizeof buf - 1], e);
490 	if (parseaddr(buf, &ee->e_from, 1, '\0', NULL, e) == NULL)
491 	{
492 		syserr("553 Can't parse myself!");
493 		ExitStat = EX_SOFTWARE;
494 		returndepth--;
495 		return (-1);
496 	}
497 	ee->e_sender = ee->e_from.q_paddr;
498 
499 	/* push state into submessage */
500 	CurEnv = ee;
501 	define('f', "\201n", ee);
502 	define('x', "Mail Delivery Subsystem", ee);
503 	eatheader(ee, TRUE);
504 
505 	/* mark statistics */
506 	markstats(ee, (ADDRESS *) NULL);
507 
508 	/* actually deliver the error message */
509 	sendall(ee, SM_DEFAULT);
510 
511 	/* restore state */
512 	dropenvelope(ee);
513 	CurEnv = oldcur;
514 	returndepth--;
515 
516 	/* should check for delivery errors here */
517 	return (0);
518 }
519 /*
520 **  ERRBODY -- output the body of an error message.
521 **
522 **	Typically this is a copy of the transcript plus a copy of the
523 **	original offending message.
524 **
525 **	Parameters:
526 **		fp -- the output file.
527 **		m -- the mailer to output to.
528 **		e -- the envelope we are working in.
529 **
530 **	Returns:
531 **		none
532 **
533 **	Side Effects:
534 **		Outputs the body of an error message.
535 */
536 
537 errbody(fp, m, e)
538 	register FILE *fp;
539 	register struct mailer *m;
540 	register ENVELOPE *e;
541 {
542 	register FILE *xfile;
543 	char *p;
544 	register ADDRESS *q;
545 	bool printheader;
546 	char buf[MAXLINE];
547 
548 	if (e->e_parent == NULL)
549 	{
550 		syserr("errbody: null parent");
551 		putline("   ----- Original message lost -----\n", fp, m);
552 		return;
553 	}
554 
555 	/*
556 	**  Output MIME header.
557 	*/
558 
559 	if (e->e_msgboundary != NULL)
560 	{
561 		putline("This is a MIME-encapsulated message", fp, m);
562 		putline("", fp, m);
563 		(void) sprintf(buf, "--%s", e->e_msgboundary);
564 		putline(buf, fp, m);
565 		putline("", fp, m);
566 	}
567 
568 	/*
569 	**  Output error message header (if specified and available).
570 	*/
571 
572 	if (ErrMsgFile != NULL)
573 	{
574 		if (*ErrMsgFile == '/')
575 		{
576 			xfile = fopen(ErrMsgFile, "r");
577 			if (xfile != NULL)
578 			{
579 				while (fgets(buf, sizeof buf, xfile) != NULL)
580 				{
581 					expand(buf, buf, &buf[sizeof buf - 1], e);
582 					putline(buf, fp, m);
583 				}
584 				(void) fclose(xfile);
585 				putline("\n", fp, m);
586 			}
587 		}
588 		else
589 		{
590 			expand(ErrMsgFile, buf, &buf[sizeof buf - 1], e);
591 			putline(buf, fp, m);
592 			putline("", fp, m);
593 		}
594 	}
595 
596 	/*
597 	**  Output message introduction
598 	*/
599 
600 	printheader = TRUE;
601 	for (q = e->e_parent->e_sendqueue; q != NULL; q = q->q_next)
602 	{
603 		if (bitset(QBADADDR|QREPORT, q->q_flags))
604 		{
605 			if (printheader)
606 			{
607 				putline("   ----- The following addresses had delivery problems -----",
608 					fp, m);
609 				printheader = FALSE;
610 			}
611 			strcpy(buf, q->q_paddr);
612 			if (bitset(QBADADDR, q->q_flags))
613 				strcat(buf, "  (unrecoverable error)");
614 			else
615 				strcat(buf, "  (transient failure)");
616 			putline(buf, fp, m);
617 			if (q->q_alias != NULL)
618 			{
619 				strcpy(buf, "    (expanded from: ");
620 				strcat(buf, q->q_alias->q_paddr);
621 				strcat(buf, ")");
622 				putline(buf, fp, m);
623 			}
624 		}
625 	}
626 	if (!printheader)
627 		putline("\n", fp, m);
628 
629 	/*
630 	**  Output transcript of errors
631 	*/
632 
633 	(void) fflush(stdout);
634 	p = queuename(e->e_parent, 'x');
635 	if ((xfile = fopen(p, "r")) == NULL)
636 	{
637 		syserr("Cannot open %s", p);
638 		putline("   ----- Transcript of session is unavailable -----\n", fp, m);
639 	}
640 	else
641 	{
642 		putline("   ----- Transcript of session follows -----\n", fp, m);
643 		if (e->e_xfp != NULL)
644 			(void) fflush(e->e_xfp);
645 		while (fgets(buf, sizeof buf, xfile) != NULL)
646 			putline(buf, fp, m);
647 		(void) xfclose(xfile, "errbody xscript", p);
648 	}
649 	errno = 0;
650 
651 	/*
652 	**  Output text of original message
653 	*/
654 
655 	if (NoReturn)
656 		SendBody = FALSE;
657 	putline("", fp, m);
658 	if (e->e_parent->e_df != NULL)
659 	{
660 		if (SendBody)
661 			putline("   ----- Unsent message follows -----\n", fp, m);
662 		else
663 			putline("   ----- Message header follows -----\n", fp, m);
664 		(void) fflush(fp);
665 
666 		if (e->e_msgboundary != NULL)
667 		{
668 			putline("", fp, m);
669 			(void) sprintf(buf, "--%s", e->e_msgboundary);
670 			putline(buf, fp, m);
671 			putline("Content-Type: message/rfc822", fp, m);
672 			putline("", fp, m);
673 		}
674 		putheader(fp, m, e->e_parent);
675 		putline("", fp, m);
676 		if (SendBody)
677 			putbody(fp, m, e->e_parent, e->e_msgboundary);
678 		else
679 			putline("   ----- Message body suppressed -----", fp, m);
680 	}
681 	else
682 	{
683 		putline("  ----- No message was collected -----\n", fp, m);
684 	}
685 
686 	if (e->e_msgboundary != NULL)
687 	{
688 		putline("", fp, m);
689 		(void) sprintf(buf, "--%s--", e->e_msgboundary);
690 		putline(buf, fp, m);
691 	}
692 	putline("", fp, m);
693 
694 	/*
695 	**  Cleanup and exit
696 	*/
697 
698 	if (errno != 0)
699 		syserr("errbody: I/O error");
700 }
701 /*
702 **  PRUNEROUTE -- prune an RFC-822 source route
703 **
704 **	Trims down a source route to the last internet-registered hop.
705 **	This is encouraged by RFC 1123 section 5.3.3.
706 **
707 **	Parameters:
708 **		addr -- the address
709 **
710 **	Returns:
711 **		TRUE -- address was modified
712 **		FALSE -- address could not be pruned
713 **
714 **	Side Effects:
715 **		modifies addr in-place
716 */
717 
718 pruneroute(addr)
719 	char *addr;
720 {
721 #ifdef NAMED_BIND
722 	char *start, *at, *comma;
723 	char c;
724 	int rcode;
725 	char hostbuf[BUFSIZ];
726 	char *mxhosts[MAXMXHOSTS + 1];
727 
728 	/* check to see if this is really a route-addr */
729 	if (*addr != '<' || addr[1] != '@' || addr[strlen(addr) - 1] != '>')
730 		return FALSE;
731 	start = strchr(addr, ':');
732 	at = strrchr(addr, '@');
733 	if (start == NULL || at == NULL || at < start)
734 		return FALSE;
735 
736 	/* slice off the angle brackets */
737 	strcpy(hostbuf, at + 1);
738 	hostbuf[strlen(hostbuf) - 1] = '\0';
739 
740 	while (start)
741 	{
742 		if (getmxrr(hostbuf, mxhosts, FALSE, &rcode) > 0)
743 		{
744 			strcpy(addr + 1, start + 1);
745 			return TRUE;
746 		}
747 		c = *start;
748 		*start = '\0';
749 		comma = strrchr(addr, ',');
750 		if (comma && comma[1] == '@')
751 			strcpy(hostbuf, comma + 2);
752 		else
753 			comma = 0;
754 		*start = c;
755 		start = comma;
756 	}
757 #endif
758 	return FALSE;
759 }
760