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	5.17 (Berkeley) 12/17/85	(no SMTP)";
19 # endif not lint
20 # else SMTP
21 
22 # ifndef lint
23 static char	SccsId[] = "@(#)srvrsmtp.c	5.17 (Berkeley) 12/17/85";
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 inp[MAXLINE];
109 	char cmdbuf[100];
110 	extern char Version[];
111 	extern tick();
112 	extern bool iswiz();
113 	extern char *arpadate();
114 	extern char *macvalue();
115 	extern ADDRESS *recipient();
116 	extern ENVELOPE BlankEnvelope;
117 	extern ENVELOPE *newenvelope();
118 
119 	hasmail = FALSE;
120 	if (OutChannel != stdout)
121 	{
122 		/* arrange for debugging output to go to remote host */
123 		(void) close(1);
124 		(void) dup(fileno(OutChannel));
125 	}
126 	settime();
127 	if (RealHostName != NULL)
128 	{
129 		CurHostName = RealHostName;
130 		setproctitle("srvrsmtp %s", CurHostName);
131 	}
132 	else
133 	{
134 		/* this must be us!! */
135 		CurHostName = MyHostName;
136 	}
137 	expand("\001e", inp, &inp[sizeof inp], CurEnv);
138 	message("220", inp);
139 	SmtpPhase = "startup";
140 	for (;;)
141 	{
142 		/* arrange for backout */
143 		if (setjmp(TopFrame) > 0 && InChild)
144 			finis();
145 		QuickAbort = FALSE;
146 		HoldErrs = FALSE;
147 
148 		/* setup for the read */
149 		CurEnv->e_to = NULL;
150 		Errors = 0;
151 		(void) fflush(stdout);
152 
153 		/* read the input line */
154 		p = sfgets(inp, sizeof inp, InChannel);
155 
156 		/* handle errors */
157 		if (p == NULL)
158 		{
159 			/* end of file, just die */
160 			message("421", "%s Lost input channel to %s",
161 				MyHostName, CurHostName);
162 			finis();
163 		}
164 
165 		/* clean up end of line */
166 		fixcrlf(inp, TRUE);
167 
168 		/* echo command to transcript */
169 		if (CurEnv->e_xfp != NULL)
170 			fprintf(CurEnv->e_xfp, "<<< %s\n", inp);
171 
172 		/* break off command */
173 		for (p = inp; isspace(*p); p++)
174 			continue;
175 		cmd = p;
176 		for (cmd = cmdbuf; *p != '\0' && !isspace(*p); )
177 			*cmd++ = *p++;
178 		*cmd = '\0';
179 
180 		/* decode command */
181 		for (c = CmdTab; c->cmdname != NULL; c++)
182 		{
183 			if (sameword(c->cmdname, cmdbuf))
184 				break;
185 		}
186 
187 		/* process command */
188 		switch (c->cmdcode)
189 		{
190 		  case CMDHELO:		/* hello -- introduce yourself */
191 			SmtpPhase = "HELO";
192 			setproctitle("%s: %s", CurHostName, inp);
193 			if (sameword(p, MyHostName))
194 			{
195 				/* connected to an echo server */
196 				message("553", "%s I refuse to talk to myself",
197 					MyHostName);
198 				break;
199 			}
200 			if (RealHostName != NULL && !sameword(p, RealHostName))
201 			{
202 				char hostbuf[MAXNAME];
203 
204 				(void) sprintf(hostbuf, "%s (%s)", p, RealHostName);
205 				define('s', newstr(hostbuf), CurEnv);
206 			}
207 			else
208 				define('s', newstr(p), CurEnv);
209 			message("250", "%s Hello %s, pleased to meet you",
210 				MyHostName, p);
211 			break;
212 
213 		  case CMDMAIL:		/* mail -- designate sender */
214 			SmtpPhase = "MAIL";
215 
216 			/* force a sending host even if no HELO given */
217 			if (RealHostName != NULL && macvalue('s', CurEnv) == NULL)
218 				define('s', RealHostName, CurEnv);
219 
220 			/* check for validity of this command */
221 			if (hasmail)
222 			{
223 				message("503", "Sender already specified");
224 				break;
225 			}
226 			if (InChild)
227 			{
228 				syserr("Nested MAIL command");
229 				exit(0);
230 			}
231 
232 			/* fork a subprocess to process this command */
233 			if (runinchild("SMTP-MAIL") > 0)
234 				break;
235 			initsys();
236 			setproctitle("%s %s: %s", CurEnv->e_id,
237 				CurHostName, inp);
238 
239 			/* child -- go do the processing */
240 			p = skipword(p, "from");
241 			if (p == NULL)
242 				break;
243 			setsender(p);
244 			if (Errors == 0)
245 			{
246 				message("250", "Sender ok");
247 				hasmail = TRUE;
248 			}
249 			else if (InChild)
250 				finis();
251 			break;
252 
253 		  case CMDRCPT:		/* rcpt -- designate recipient */
254 			SmtpPhase = "RCPT";
255 			setproctitle("%s %s: %s", CurEnv->e_id,
256 				CurHostName, inp);
257 			if (setjmp(TopFrame) > 0)
258 			{
259 				CurEnv->e_flags &= ~EF_FATALERRS;
260 				break;
261 			}
262 			QuickAbort = TRUE;
263 			p = skipword(p, "to");
264 			if (p == NULL)
265 				break;
266 			a = parseaddr(p, (ADDRESS *) NULL, 1, '\0');
267 			if (a == NULL)
268 				break;
269 			a->q_flags |= QPRIMARY;
270 			a = recipient(a, &CurEnv->e_sendqueue);
271 			if (Errors != 0)
272 				break;
273 
274 			/* no errors during parsing, but might be a duplicate */
275 			CurEnv->e_to = p;
276 			if (!bitset(QBADADDR, a->q_flags))
277 				message("250", "Recipient ok");
278 			else
279 			{
280 				/* punt -- should keep message in ADDRESS.... */
281 				message("550", "Addressee unknown");
282 			}
283 			CurEnv->e_to = NULL;
284 			break;
285 
286 		  case CMDDATA:		/* data -- text of mail */
287 			SmtpPhase = "DATA";
288 			if (!hasmail)
289 			{
290 				message("503", "Need MAIL command");
291 				break;
292 			}
293 			else if (CurEnv->e_nrcpts <= 0)
294 			{
295 				message("503", "Need RCPT (recipient)");
296 				break;
297 			}
298 
299 			/* collect the text of the message */
300 			SmtpPhase = "collect";
301 			setproctitle("%s %s: %s", CurEnv->e_id,
302 				CurHostName, inp);
303 			collect(TRUE);
304 			if (Errors != 0)
305 				break;
306 
307 			/*
308 			**  Arrange to send to everyone.
309 			**	If sending to multiple people, mail back
310 			**		errors rather than reporting directly.
311 			**	In any case, don't mail back errors for
312 			**		anything that has happened up to
313 			**		now (the other end will do this).
314 			**	Truncate our transcript -- the mail has gotten
315 			**		to us successfully, and if we have
316 			**		to mail this back, it will be easier
317 			**		on the reader.
318 			**	Then send to everyone.
319 			**	Finally give a reply code.  If an error has
320 			**		already been given, don't mail a
321 			**		message back.
322 			**	We goose error returns by clearing error bit.
323 			*/
324 
325 			SmtpPhase = "delivery";
326 			if (CurEnv->e_nrcpts != 1)
327 			{
328 				HoldErrs = TRUE;
329 				ErrorMode = EM_MAIL;
330 			}
331 			CurEnv->e_flags &= ~EF_FATALERRS;
332 			CurEnv->e_xfp = freopen(queuename(CurEnv, 'x'), "w", CurEnv->e_xfp);
333 
334 			/* send to all recipients */
335 			sendall(CurEnv, SM_DEFAULT);
336 			CurEnv->e_to = NULL;
337 
338 			/* save statistics */
339 			markstats(CurEnv, (ADDRESS *) NULL);
340 
341 			/* issue success if appropriate and reset */
342 			if (Errors == 0 || HoldErrs)
343 				message("250", "Ok");
344 			else
345 				CurEnv->e_flags &= ~EF_FATALERRS;
346 
347 			/* if in a child, pop back to our parent */
348 			if (InChild)
349 				finis();
350 
351 			/* clean up a bit */
352 			hasmail = 0;
353 			dropenvelope(CurEnv);
354 			CurEnv = newenvelope(CurEnv);
355 			CurEnv->e_flags = BlankEnvelope.e_flags;
356 			break;
357 
358 		  case CMDRSET:		/* rset -- reset state */
359 			message("250", "Reset state");
360 			if (InChild)
361 				finis();
362 			break;
363 
364 		  case CMDVRFY:		/* vrfy -- verify address */
365 			if (runinchild("SMTP-VRFY") > 0)
366 				break;
367 			setproctitle("%s: %s", CurHostName, inp);
368 			vrfyqueue = NULL;
369 			QuickAbort = TRUE;
370 			sendtolist(p, (ADDRESS *) NULL, &vrfyqueue);
371 			if (Errors != 0)
372 			{
373 				if (InChild)
374 					finis();
375 				break;
376 			}
377 			while (vrfyqueue != NULL)
378 			{
379 				register ADDRESS *a = vrfyqueue->q_next;
380 				char *code;
381 
382 				while (a != NULL && bitset(QDONTSEND|QBADADDR, a->q_flags))
383 					a = a->q_next;
384 
385 				if (!bitset(QDONTSEND|QBADADDR, vrfyqueue->q_flags))
386 				{
387 					if (a != NULL)
388 						code = "250-";
389 					else
390 						code = "250";
391 					if (vrfyqueue->q_fullname == NULL)
392 						message(code, "<%s>", vrfyqueue->q_paddr);
393 					else
394 						message(code, "%s <%s>",
395 						    vrfyqueue->q_fullname, vrfyqueue->q_paddr);
396 				}
397 				else if (a == NULL)
398 					message("554", "Self destructive alias loop");
399 				vrfyqueue = a;
400 			}
401 			if (InChild)
402 				finis();
403 			break;
404 
405 		  case CMDHELP:		/* help -- give user info */
406 			if (*p == '\0')
407 				p = "SMTP";
408 			help(p);
409 			break;
410 
411 		  case CMDNOOP:		/* noop -- do nothing */
412 			message("200", "OK");
413 			break;
414 
415 		  case CMDQUIT:		/* quit -- leave mail */
416 			message("221", "%s closing connection", MyHostName);
417 			if (InChild)
418 				ExitStat = EX_QUIT;
419 			finis();
420 
421 		  case CMDVERB:		/* set verbose mode */
422 			Verbose = TRUE;
423 			SendMode = SM_DELIVER;
424 			message("200", "Verbose mode");
425 			break;
426 
427 		  case CMDONEX:		/* doing one transaction only */
428 			OneXact = TRUE;
429 			message("200", "Only one transaction");
430 			break;
431 
432 # ifdef DEBUG
433 		  case CMDDBGQSHOW:	/* show queues */
434 			printf("Send Queue=");
435 			printaddr(CurEnv->e_sendqueue, TRUE);
436 			break;
437 
438 		  case CMDDBGDEBUG:	/* set debug mode */
439 			tTsetup(tTdvect, sizeof tTdvect, "0-99.1");
440 			tTflag(p);
441 			message("200", "Debug set");
442 			break;
443 # endif DEBUG
444 
445 # ifdef WIZ
446 		  case CMDDBGKILL:	/* kill the parent */
447 			if (!iswiz())
448 				break;
449 			if (kill(MotherPid, SIGTERM) >= 0)
450 				message("200", "Mother is dead");
451 			else
452 				message("500", "Can't kill Mom");
453 			break;
454 
455 		  case CMDDBGWIZ:	/* become a wizard */
456 			if (WizWord != NULL)
457 			{
458 				char seed[3];
459 				extern char *crypt();
460 
461 				(void) strncpy(seed, WizWord, 2);
462 				if (strcmp(WizWord, crypt(p, seed)) == 0)
463 				{
464 					IsWiz = TRUE;
465 					message("200", "Please pass, oh mighty wizard");
466 					break;
467 				}
468 			}
469 			message("500", "You are no wizard!");
470 			break;
471 
472 # else WIZ
473 		  case CMDDBGWIZ:	/* try to become a wizard */
474 			message("500", "You wascal wabbit!  Wandering wizards won't win!");
475 			break;
476 # endif WIZ
477 
478 		  case CMDERROR:	/* unknown command */
479 			message("500", "Command unrecognized");
480 			break;
481 
482 		  default:
483 			syserr("smtp: unknown code %d", c->cmdcode);
484 			break;
485 		}
486 	}
487 }
488 /*
489 **  SKIPWORD -- skip a fixed word.
490 **
491 **	Parameters:
492 **		p -- place to start looking.
493 **		w -- word to skip.
494 **
495 **	Returns:
496 **		p following w.
497 **		NULL on error.
498 **
499 **	Side Effects:
500 **		clobbers the p data area.
501 */
502 
503 static char *
504 skipword(p, w)
505 	register char *p;
506 	char *w;
507 {
508 	register char *q;
509 	extern bool sameword();
510 
511 	/* find beginning of word */
512 	while (isspace(*p))
513 		p++;
514 	q = p;
515 
516 	/* find end of word */
517 	while (*p != '\0' && *p != ':' && !isspace(*p))
518 		p++;
519 	while (isspace(*p))
520 		*p++ = '\0';
521 	if (*p != ':')
522 	{
523 	  syntax:
524 		message("501", "Syntax error");
525 		Errors++;
526 		return (NULL);
527 	}
528 	*p++ = '\0';
529 	while (isspace(*p))
530 		p++;
531 
532 	/* see if the input word matches desired word */
533 	if (!sameword(q, w))
534 		goto syntax;
535 
536 	return (p);
537 }
538 /*
539 **  HELP -- implement the HELP command.
540 **
541 **	Parameters:
542 **		topic -- the topic we want help for.
543 **
544 **	Returns:
545 **		none.
546 **
547 **	Side Effects:
548 **		outputs the help file to message output.
549 */
550 
551 help(topic)
552 	char *topic;
553 {
554 	register FILE *hf;
555 	int len;
556 	char buf[MAXLINE];
557 	bool noinfo;
558 
559 	if (HelpFile == NULL || (hf = fopen(HelpFile, "r")) == NULL)
560 	{
561 		/* no help */
562 		errno = 0;
563 		message("502", "HELP not implemented");
564 		return;
565 	}
566 
567 	len = strlen(topic);
568 	makelower(topic);
569 	noinfo = TRUE;
570 
571 	while (fgets(buf, sizeof buf, hf) != NULL)
572 	{
573 		if (strncmp(buf, topic, len) == 0)
574 		{
575 			register char *p;
576 
577 			p = index(buf, '\t');
578 			if (p == NULL)
579 				p = buf;
580 			else
581 				p++;
582 			fixcrlf(p, TRUE);
583 			message("214-", p);
584 			noinfo = FALSE;
585 		}
586 	}
587 
588 	if (noinfo)
589 		message("504", "HELP topic unknown");
590 	else
591 		message("214", "End of HELP info");
592 	(void) fclose(hf);
593 }
594 /*
595 **  ISWIZ -- tell us if we are a wizard
596 **
597 **	If not, print a nasty message.
598 **
599 **	Parameters:
600 **		none.
601 **
602 **	Returns:
603 **		TRUE if we are a wizard.
604 **		FALSE if we are not a wizard.
605 **
606 **	Side Effects:
607 **		Prints a 500 exit stat if we are not a wizard.
608 */
609 
610 #ifdef WIZ
611 
612 bool
613 iswiz()
614 {
615 	if (!IsWiz)
616 		message("500", "Mere mortals musn't mutter that mantra");
617 	return (IsWiz);
618 }
619 
620 #endif WIZ
621 /*
622 **  RUNINCHILD -- return twice -- once in the child, then in the parent again
623 **
624 **	Parameters:
625 **		label -- a string used in error messages
626 **
627 **	Returns:
628 **		zero in the child
629 **		one in the parent
630 **
631 **	Side Effects:
632 **		none.
633 */
634 
635 runinchild(label)
636 	char *label;
637 {
638 	int childpid;
639 
640 	if (!OneXact)
641 	{
642 		childpid = dofork();
643 		if (childpid < 0)
644 		{
645 			syserr("%s: cannot fork", label);
646 			return (1);
647 		}
648 		if (childpid > 0)
649 		{
650 			auto int st;
651 
652 			/* parent -- wait for child to complete */
653 			st = waitfor(childpid);
654 			if (st == -1)
655 				syserr("%s: lost child", label);
656 
657 			/* if we exited on a QUIT command, complete the process */
658 			if (st == (EX_QUIT << 8))
659 				finis();
660 
661 			return (1);
662 		}
663 		else
664 		{
665 			/* child */
666 			InChild = TRUE;
667 			QuickAbort = FALSE;
668 			clearenvelope(CurEnv, FALSE);
669 		}
670 	}
671 
672 	/* open alias database */
673 	initaliases(AliasFile, FALSE);
674 
675 	return (0);
676 }
677 
678 # endif SMTP
679