1 /*
2 **  Sendmail
3 **  Copyright (c) 1983  Eric P. Allman
4 **  Berkeley, California
5 **
6 **  Copyright (c) 1983 Regents of the University of California.
7 **  All rights reserved.  The Berkeley software License Agreement
8 **  specifies the terms and conditions for redistribution.
9 */
10 
11 
12 # include <errno.h>
13 # include "sendmail.h"
14 # include <signal.h>
15 
16 # ifndef SMTP
17 # ifndef lint
18 static char	SccsId[] = "@(#)srvrsmtp.c	5.19 (Berkeley) 02/03/87	(no SMTP)";
19 # endif not lint
20 # else SMTP
21 
22 # ifndef lint
23 static char	SccsId[] = "@(#)srvrsmtp.c	5.19 (Berkeley) 02/03/87";
24 # endif not lint
25 
26 /*
27 **  SMTP -- run the SMTP protocol.
28 **
29 **	Parameters:
30 **		none.
31 **
32 **	Returns:
33 **		never.
34 **
35 **	Side Effects:
36 **		Reads commands from the input channel and processes
37 **			them.
38 */
39 
40 struct cmd
41 {
42 	char	*cmdname;	/* command name */
43 	int	cmdcode;	/* internal code, see below */
44 };
45 
46 /* values for cmdcode */
47 # define CMDERROR	0	/* bad command */
48 # define CMDMAIL	1	/* mail -- designate sender */
49 # define CMDRCPT	2	/* rcpt -- designate recipient */
50 # define CMDDATA	3	/* data -- send message text */
51 # define CMDRSET	4	/* rset -- reset state */
52 # define CMDVRFY	5	/* vrfy -- verify address */
53 # define CMDHELP	6	/* help -- give usage info */
54 # define CMDNOOP	7	/* noop -- do nothing */
55 # define CMDQUIT	8	/* quit -- close connection and die */
56 # define CMDHELO	9	/* helo -- be polite */
57 # define CMDDBGQSHOW	10	/* showq -- show send queue (DEBUG) */
58 # define CMDDBGDEBUG	11	/* debug -- set debug mode */
59 # define CMDVERB	12	/* verb -- go into verbose mode */
60 # define CMDDBGKILL	13	/* kill -- kill sendmail */
61 # define CMDDBGWIZ	14	/* wiz -- become a wizard */
62 # define CMDONEX	15	/* onex -- sending one transaction only */
63 
64 static struct cmd	CmdTab[] =
65 {
66 	"mail",		CMDMAIL,
67 	"rcpt",		CMDRCPT,
68 	"data",		CMDDATA,
69 	"rset",		CMDRSET,
70 	"vrfy",		CMDVRFY,
71 	"expn",		CMDVRFY,
72 	"help",		CMDHELP,
73 	"noop",		CMDNOOP,
74 	"quit",		CMDQUIT,
75 	"helo",		CMDHELO,
76 	"verb",		CMDVERB,
77 	"onex",		CMDONEX,
78 # ifdef DEBUG
79 	"showq",	CMDDBGQSHOW,
80 	"debug",	CMDDBGDEBUG,
81 # endif DEBUG
82 # ifdef WIZ
83 	"kill",		CMDDBGKILL,
84 # endif WIZ
85 	"wiz",		CMDDBGWIZ,
86 	NULL,		CMDERROR,
87 };
88 
89 # ifdef WIZ
90 bool	IsWiz = FALSE;			/* set if we are a wizard */
91 # endif WIZ
92 char	*WizWord;			/* the wizard word to compare against */
93 bool	InChild = FALSE;		/* true if running in a subprocess */
94 bool	OneXact = FALSE;		/* one xaction only this run */
95 
96 #define EX_QUIT		22		/* special code for QUIT command */
97 
98 smtp()
99 {
100 	register char *p;
101 	register struct cmd *c;
102 	char *cmd;
103 	extern char *skipword();
104 	extern bool sameword();
105 	bool hasmail;			/* mail command received */
106 	auto ADDRESS *vrfyqueue;
107 	ADDRESS *a;
108 	char *sendinghost;
109 	char inp[MAXLINE];
110 	char cmdbuf[100];
111 	extern char Version[];
112 	extern tick();
113 	extern bool iswiz();
114 	extern char *arpadate();
115 	extern char *macvalue();
116 	extern ADDRESS *recipient();
117 	extern ENVELOPE BlankEnvelope;
118 	extern ENVELOPE *newenvelope();
119 
120 	hasmail = FALSE;
121 	if (OutChannel != stdout)
122 	{
123 		/* arrange for debugging output to go to remote host */
124 		(void) close(1);
125 		(void) dup(fileno(OutChannel));
126 	}
127 	settime();
128 	if (RealHostName != NULL)
129 	{
130 		CurHostName = RealHostName;
131 		setproctitle("srvrsmtp %s", CurHostName);
132 	}
133 	else
134 	{
135 		/* this must be us!! */
136 		CurHostName = MyHostName;
137 	}
138 	expand("\001e", inp, &inp[sizeof inp], CurEnv);
139 	message("220", inp);
140 	SmtpPhase = "startup";
141 	sendinghost = NULL;
142 	for (;;)
143 	{
144 		/* arrange for backout */
145 		if (setjmp(TopFrame) > 0 && InChild)
146 			finis();
147 		QuickAbort = FALSE;
148 		HoldErrs = FALSE;
149 
150 		/* setup for the read */
151 		CurEnv->e_to = NULL;
152 		Errors = 0;
153 		(void) fflush(stdout);
154 
155 		/* read the input line */
156 		p = sfgets(inp, sizeof inp, InChannel);
157 
158 		/* handle errors */
159 		if (p == NULL)
160 		{
161 			/* end of file, just die */
162 			message("421", "%s Lost input channel to %s",
163 				MyHostName, CurHostName);
164 			finis();
165 		}
166 
167 		/* clean up end of line */
168 		fixcrlf(inp, TRUE);
169 
170 		/* echo command to transcript */
171 		if (CurEnv->e_xfp != NULL)
172 			fprintf(CurEnv->e_xfp, "<<< %s\n", inp);
173 
174 		/* break off command */
175 		for (p = inp; isspace(*p); p++)
176 			continue;
177 		cmd = p;
178 		for (cmd = cmdbuf; *p != '\0' && !isspace(*p); )
179 			*cmd++ = *p++;
180 		*cmd = '\0';
181 
182 		/* throw away leading whitespace */
183 		while (isspace(*p))
184 			p++;
185 
186 		/* decode command */
187 		for (c = CmdTab; c->cmdname != NULL; c++)
188 		{
189 			if (sameword(c->cmdname, cmdbuf))
190 				break;
191 		}
192 
193 		/* process command */
194 		switch (c->cmdcode)
195 		{
196 		  case CMDHELO:		/* hello -- introduce yourself */
197 			SmtpPhase = "HELO";
198 			setproctitle("%s: %s", CurHostName, inp);
199 			if (sameword(p, MyHostName))
200 			{
201 				/* connected to an echo server */
202 				message("553", "%s I refuse to talk to myself",
203 					MyHostName);
204 				break;
205 			}
206 			if (RealHostName != NULL && !sameword(p, RealHostName))
207 			{
208 				char hostbuf[MAXNAME];
209 
210 				(void) sprintf(hostbuf, "%s (%s)", p, RealHostName);
211 				sendinghost = newstr(hostbuf);
212 			}
213 			else
214 				sendinghost = newstr(p);
215 			message("250", "%s Hello %s, pleased to meet you",
216 				MyHostName, p);
217 			break;
218 
219 		  case CMDMAIL:		/* mail -- designate sender */
220 			SmtpPhase = "MAIL";
221 
222 			/* force a sending host even if no HELO given */
223 			if (RealHostName != NULL && macvalue('s', CurEnv) == NULL)
224 				sendinghost = RealHostName;
225 
226 			/* check for validity of this command */
227 			if (hasmail)
228 			{
229 				message("503", "Sender already specified");
230 				break;
231 			}
232 			if (InChild)
233 			{
234 				syserr("Nested MAIL command");
235 				exit(0);
236 			}
237 
238 			/* fork a subprocess to process this command */
239 			if (runinchild("SMTP-MAIL") > 0)
240 				break;
241 			define('s', sendinghost, CurEnv);
242 			initsys();
243 			setproctitle("%s %s: %s", CurEnv->e_id,
244 				CurHostName, inp);
245 
246 			/* child -- go do the processing */
247 			p = skipword(p, "from");
248 			if (p == NULL)
249 				break;
250 			setsender(p);
251 			if (Errors == 0)
252 			{
253 				message("250", "Sender ok");
254 				hasmail = TRUE;
255 			}
256 			else if (InChild)
257 				finis();
258 			break;
259 
260 		  case CMDRCPT:		/* rcpt -- designate recipient */
261 			SmtpPhase = "RCPT";
262 			setproctitle("%s %s: %s", CurEnv->e_id,
263 				CurHostName, inp);
264 			if (setjmp(TopFrame) > 0)
265 			{
266 				CurEnv->e_flags &= ~EF_FATALERRS;
267 				break;
268 			}
269 			QuickAbort = TRUE;
270 			p = skipword(p, "to");
271 			if (p == NULL)
272 				break;
273 			a = parseaddr(p, (ADDRESS *) NULL, 1, '\0');
274 			if (a == NULL)
275 				break;
276 			a->q_flags |= QPRIMARY;
277 			a = recipient(a, &CurEnv->e_sendqueue);
278 			if (Errors != 0)
279 				break;
280 
281 			/* no errors during parsing, but might be a duplicate */
282 			CurEnv->e_to = p;
283 			if (!bitset(QBADADDR, a->q_flags))
284 				message("250", "Recipient ok");
285 			else
286 			{
287 				/* punt -- should keep message in ADDRESS.... */
288 				message("550", "Addressee unknown");
289 			}
290 			CurEnv->e_to = NULL;
291 			break;
292 
293 		  case CMDDATA:		/* data -- text of mail */
294 			SmtpPhase = "DATA";
295 			if (!hasmail)
296 			{
297 				message("503", "Need MAIL command");
298 				break;
299 			}
300 			else if (CurEnv->e_nrcpts <= 0)
301 			{
302 				message("503", "Need RCPT (recipient)");
303 				break;
304 			}
305 
306 			/* collect the text of the message */
307 			SmtpPhase = "collect";
308 			setproctitle("%s %s: %s", CurEnv->e_id,
309 				CurHostName, inp);
310 			collect(TRUE);
311 			if (Errors != 0)
312 				break;
313 
314 			/*
315 			**  Arrange to send to everyone.
316 			**	If sending to multiple people, mail back
317 			**		errors rather than reporting directly.
318 			**	In any case, don't mail back errors for
319 			**		anything that has happened up to
320 			**		now (the other end will do this).
321 			**	Truncate our transcript -- the mail has gotten
322 			**		to us successfully, and if we have
323 			**		to mail this back, it will be easier
324 			**		on the reader.
325 			**	Then send to everyone.
326 			**	Finally give a reply code.  If an error has
327 			**		already been given, don't mail a
328 			**		message back.
329 			**	We goose error returns by clearing error bit.
330 			*/
331 
332 			SmtpPhase = "delivery";
333 			if (CurEnv->e_nrcpts != 1)
334 			{
335 				HoldErrs = TRUE;
336 				ErrorMode = EM_MAIL;
337 			}
338 			CurEnv->e_flags &= ~EF_FATALERRS;
339 			CurEnv->e_xfp = freopen(queuename(CurEnv, 'x'), "w", CurEnv->e_xfp);
340 
341 			/* send to all recipients */
342 			sendall(CurEnv, SM_DEFAULT);
343 			CurEnv->e_to = NULL;
344 
345 			/* save statistics */
346 			markstats(CurEnv, (ADDRESS *) NULL);
347 
348 			/* issue success if appropriate and reset */
349 			if (Errors == 0 || HoldErrs)
350 				message("250", "Ok");
351 			else
352 				CurEnv->e_flags &= ~EF_FATALERRS;
353 
354 			/* if in a child, pop back to our parent */
355 			if (InChild)
356 				finis();
357 
358 			/* clean up a bit */
359 			hasmail = 0;
360 			dropenvelope(CurEnv);
361 			CurEnv = newenvelope(CurEnv);
362 			CurEnv->e_flags = BlankEnvelope.e_flags;
363 			break;
364 
365 		  case CMDRSET:		/* rset -- reset state */
366 			message("250", "Reset state");
367 			if (InChild)
368 				finis();
369 			break;
370 
371 		  case CMDVRFY:		/* vrfy -- verify address */
372 			if (runinchild("SMTP-VRFY") > 0)
373 				break;
374 			setproctitle("%s: %s", CurHostName, inp);
375 			vrfyqueue = NULL;
376 			QuickAbort = TRUE;
377 			sendtolist(p, (ADDRESS *) NULL, &vrfyqueue);
378 			if (Errors != 0)
379 			{
380 				if (InChild)
381 					finis();
382 				break;
383 			}
384 			while (vrfyqueue != NULL)
385 			{
386 				register ADDRESS *a = vrfyqueue->q_next;
387 				char *code;
388 
389 				while (a != NULL && bitset(QDONTSEND|QBADADDR, a->q_flags))
390 					a = a->q_next;
391 
392 				if (!bitset(QDONTSEND|QBADADDR, vrfyqueue->q_flags))
393 				{
394 					if (a != NULL)
395 						code = "250-";
396 					else
397 						code = "250";
398 					if (vrfyqueue->q_fullname == NULL)
399 						message(code, "<%s>", vrfyqueue->q_paddr);
400 					else
401 						message(code, "%s <%s>",
402 						    vrfyqueue->q_fullname, vrfyqueue->q_paddr);
403 				}
404 				else if (a == NULL)
405 					message("554", "Self destructive alias loop");
406 				vrfyqueue = a;
407 			}
408 			if (InChild)
409 				finis();
410 			break;
411 
412 		  case CMDHELP:		/* help -- give user info */
413 			if (*p == '\0')
414 				p = "SMTP";
415 			help(p);
416 			break;
417 
418 		  case CMDNOOP:		/* noop -- do nothing */
419 			message("200", "OK");
420 			break;
421 
422 		  case CMDQUIT:		/* quit -- leave mail */
423 			message("221", "%s closing connection", MyHostName);
424 			if (InChild)
425 				ExitStat = EX_QUIT;
426 			finis();
427 
428 		  case CMDVERB:		/* set verbose mode */
429 			Verbose = TRUE;
430 			SendMode = SM_DELIVER;
431 			message("200", "Verbose mode");
432 			break;
433 
434 		  case CMDONEX:		/* doing one transaction only */
435 			OneXact = TRUE;
436 			message("200", "Only one transaction");
437 			break;
438 
439 # ifdef DEBUG
440 		  case CMDDBGQSHOW:	/* show queues */
441 			printf("Send Queue=");
442 			printaddr(CurEnv->e_sendqueue, TRUE);
443 			break;
444 
445 		  case CMDDBGDEBUG:	/* set debug mode */
446 			tTsetup(tTdvect, sizeof tTdvect, "0-99.1");
447 			tTflag(p);
448 			message("200", "Debug set");
449 			break;
450 # endif DEBUG
451 
452 # ifdef WIZ
453 		  case CMDDBGKILL:	/* kill the parent */
454 			if (!iswiz())
455 				break;
456 			if (kill(MotherPid, SIGTERM) >= 0)
457 				message("200", "Mother is dead");
458 			else
459 				message("500", "Can't kill Mom");
460 			break;
461 
462 		  case CMDDBGWIZ:	/* become a wizard */
463 			if (WizWord != NULL)
464 			{
465 				char seed[3];
466 				extern char *crypt();
467 
468 				(void) strncpy(seed, WizWord, 2);
469 				if (strcmp(WizWord, crypt(p, seed)) == 0)
470 				{
471 					IsWiz = TRUE;
472 					message("200", "Please pass, oh mighty wizard");
473 					break;
474 				}
475 			}
476 			message("500", "You are no wizard!");
477 			break;
478 
479 # else WIZ
480 		  case CMDDBGWIZ:	/* try to become a wizard */
481 			message("500", "You wascal wabbit!  Wandering wizards won't win!");
482 			break;
483 # endif WIZ
484 
485 		  case CMDERROR:	/* unknown command */
486 			message("500", "Command unrecognized");
487 			break;
488 
489 		  default:
490 			syserr("smtp: unknown code %d", c->cmdcode);
491 			break;
492 		}
493 	}
494 }
495 /*
496 **  SKIPWORD -- skip a fixed word.
497 **
498 **	Parameters:
499 **		p -- place to start looking.
500 **		w -- word to skip.
501 **
502 **	Returns:
503 **		p following w.
504 **		NULL on error.
505 **
506 **	Side Effects:
507 **		clobbers the p data area.
508 */
509 
510 static char *
511 skipword(p, w)
512 	register char *p;
513 	char *w;
514 {
515 	register char *q;
516 	extern bool sameword();
517 
518 	/* find beginning of word */
519 	while (isspace(*p))
520 		p++;
521 	q = p;
522 
523 	/* find end of word */
524 	while (*p != '\0' && *p != ':' && !isspace(*p))
525 		p++;
526 	while (isspace(*p))
527 		*p++ = '\0';
528 	if (*p != ':')
529 	{
530 	  syntax:
531 		message("501", "Syntax error");
532 		Errors++;
533 		return (NULL);
534 	}
535 	*p++ = '\0';
536 	while (isspace(*p))
537 		p++;
538 
539 	/* see if the input word matches desired word */
540 	if (!sameword(q, w))
541 		goto syntax;
542 
543 	return (p);
544 }
545 /*
546 **  HELP -- implement the HELP command.
547 **
548 **	Parameters:
549 **		topic -- the topic we want help for.
550 **
551 **	Returns:
552 **		none.
553 **
554 **	Side Effects:
555 **		outputs the help file to message output.
556 */
557 
558 help(topic)
559 	char *topic;
560 {
561 	register FILE *hf;
562 	int len;
563 	char buf[MAXLINE];
564 	bool noinfo;
565 
566 	if (HelpFile == NULL || (hf = fopen(HelpFile, "r")) == NULL)
567 	{
568 		/* no help */
569 		errno = 0;
570 		message("502", "HELP not implemented");
571 		return;
572 	}
573 
574 	len = strlen(topic);
575 	makelower(topic);
576 	noinfo = TRUE;
577 
578 	while (fgets(buf, sizeof buf, hf) != NULL)
579 	{
580 		if (strncmp(buf, topic, len) == 0)
581 		{
582 			register char *p;
583 
584 			p = index(buf, '\t');
585 			if (p == NULL)
586 				p = buf;
587 			else
588 				p++;
589 			fixcrlf(p, TRUE);
590 			message("214-", p);
591 			noinfo = FALSE;
592 		}
593 	}
594 
595 	if (noinfo)
596 		message("504", "HELP topic unknown");
597 	else
598 		message("214", "End of HELP info");
599 	(void) fclose(hf);
600 }
601 /*
602 **  ISWIZ -- tell us if we are a wizard
603 **
604 **	If not, print a nasty message.
605 **
606 **	Parameters:
607 **		none.
608 **
609 **	Returns:
610 **		TRUE if we are a wizard.
611 **		FALSE if we are not a wizard.
612 **
613 **	Side Effects:
614 **		Prints a 500 exit stat if we are not a wizard.
615 */
616 
617 #ifdef WIZ
618 
619 bool
620 iswiz()
621 {
622 	if (!IsWiz)
623 		message("500", "Mere mortals musn't mutter that mantra");
624 	return (IsWiz);
625 }
626 
627 #endif WIZ
628 /*
629 **  RUNINCHILD -- return twice -- once in the child, then in the parent again
630 **
631 **	Parameters:
632 **		label -- a string used in error messages
633 **
634 **	Returns:
635 **		zero in the child
636 **		one in the parent
637 **
638 **	Side Effects:
639 **		none.
640 */
641 
642 runinchild(label)
643 	char *label;
644 {
645 	int childpid;
646 
647 	if (!OneXact)
648 	{
649 		childpid = dofork();
650 		if (childpid < 0)
651 		{
652 			syserr("%s: cannot fork", label);
653 			return (1);
654 		}
655 		if (childpid > 0)
656 		{
657 			auto int st;
658 
659 			/* parent -- wait for child to complete */
660 			st = waitfor(childpid);
661 			if (st == -1)
662 				syserr("%s: lost child", label);
663 
664 			/* if we exited on a QUIT command, complete the process */
665 			if (st == (EX_QUIT << 8))
666 				finis();
667 
668 			return (1);
669 		}
670 		else
671 		{
672 			/* child */
673 			InChild = TRUE;
674 			QuickAbort = FALSE;
675 			clearenvelope(CurEnv, FALSE);
676 		}
677 	}
678 
679 	/* open alias database */
680 	initaliases(AliasFile, FALSE);
681 
682 	return (0);
683 }
684 
685 # endif SMTP
686