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	5.20 (Berkeley) 03/13/88	(no SMTP)";
19 # endif not lint
20 # else SMTP
21 
22 # ifndef lint
23 static char	SccsId[] = "@(#)srvrsmtp.c	5.20 (Berkeley) 03/13/88";
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 	bool hasmail;			/* mail command received */
105 	auto ADDRESS *vrfyqueue;
106 	ADDRESS *a;
107 	char *sendinghost;
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 	sendinghost = NULL;
141 	for (;;)
142 	{
143 		/* arrange for backout */
144 		if (setjmp(TopFrame) > 0 && InChild)
145 			finis();
146 		QuickAbort = FALSE;
147 		HoldErrs = FALSE;
148 
149 		/* setup for the read */
150 		CurEnv->e_to = NULL;
151 		Errors = 0;
152 		(void) fflush(stdout);
153 
154 		/* read the input line */
155 		p = sfgets(inp, sizeof inp, InChannel);
156 
157 		/* handle errors */
158 		if (p == NULL)
159 		{
160 			/* end of file, just die */
161 			message("421", "%s Lost input channel to %s",
162 				MyHostName, CurHostName);
163 			finis();
164 		}
165 
166 		/* clean up end of line */
167 		fixcrlf(inp, TRUE);
168 
169 		/* echo command to transcript */
170 		if (CurEnv->e_xfp != NULL)
171 			fprintf(CurEnv->e_xfp, "<<< %s\n", inp);
172 
173 		/* break off command */
174 		for (p = inp; isspace(*p); p++)
175 			continue;
176 		cmd = p;
177 		for (cmd = cmdbuf; *p != '\0' && !isspace(*p); )
178 			*cmd++ = *p++;
179 		*cmd = '\0';
180 
181 		/* throw away leading whitespace */
182 		while (isspace(*p))
183 			p++;
184 
185 		/* decode command */
186 		for (c = CmdTab; c->cmdname != NULL; c++)
187 		{
188 			if (!strcasecmp(c->cmdname, cmdbuf))
189 				break;
190 		}
191 
192 		/* process command */
193 		switch (c->cmdcode)
194 		{
195 		  case CMDHELO:		/* hello -- introduce yourself */
196 			SmtpPhase = "HELO";
197 			setproctitle("%s: %s", CurHostName, inp);
198 			if (!strcasecmp(p, MyHostName))
199 			{
200 				/* connected to an echo server */
201 				message("553", "%s I refuse to talk to myself",
202 					MyHostName);
203 				break;
204 			}
205 			if (RealHostName != NULL && strcasecmp(p, RealHostName))
206 			{
207 				char hostbuf[MAXNAME];
208 
209 				(void) sprintf(hostbuf, "%s (%s)", p, RealHostName);
210 				sendinghost = newstr(hostbuf);
211 			}
212 			else
213 				sendinghost = newstr(p);
214 			message("250", "%s Hello %s, pleased to meet you",
215 				MyHostName, p);
216 			break;
217 
218 		  case CMDMAIL:		/* mail -- designate sender */
219 			SmtpPhase = "MAIL";
220 
221 			/* force a sending host even if no HELO given */
222 			if (RealHostName != NULL && macvalue('s', CurEnv) == NULL)
223 				sendinghost = RealHostName;
224 
225 			/* check for validity of this command */
226 			if (hasmail)
227 			{
228 				message("503", "Sender already specified");
229 				break;
230 			}
231 			if (InChild)
232 			{
233 				syserr("Nested MAIL command");
234 				exit(0);
235 			}
236 
237 			/* fork a subprocess to process this command */
238 			if (runinchild("SMTP-MAIL") > 0)
239 				break;
240 			define('s', sendinghost, CurEnv);
241 			initsys();
242 			setproctitle("%s %s: %s", CurEnv->e_id,
243 				CurHostName, inp);
244 
245 			/* child -- go do the processing */
246 			p = skipword(p, "from");
247 			if (p == NULL)
248 				break;
249 			setsender(p);
250 			if (Errors == 0)
251 			{
252 				message("250", "Sender ok");
253 				hasmail = TRUE;
254 			}
255 			else if (InChild)
256 				finis();
257 			break;
258 
259 		  case CMDRCPT:		/* rcpt -- designate recipient */
260 			SmtpPhase = "RCPT";
261 			setproctitle("%s %s: %s", CurEnv->e_id,
262 				CurHostName, inp);
263 			if (setjmp(TopFrame) > 0)
264 			{
265 				CurEnv->e_flags &= ~EF_FATALERRS;
266 				break;
267 			}
268 			QuickAbort = TRUE;
269 			p = skipword(p, "to");
270 			if (p == NULL)
271 				break;
272 			a = parseaddr(p, (ADDRESS *) NULL, 1, '\0');
273 			if (a == NULL)
274 				break;
275 			a->q_flags |= QPRIMARY;
276 			a = recipient(a, &CurEnv->e_sendqueue);
277 			if (Errors != 0)
278 				break;
279 
280 			/* no errors during parsing, but might be a duplicate */
281 			CurEnv->e_to = p;
282 			if (!bitset(QBADADDR, a->q_flags))
283 				message("250", "Recipient ok");
284 			else
285 			{
286 				/* punt -- should keep message in ADDRESS.... */
287 				message("550", "Addressee unknown");
288 			}
289 			CurEnv->e_to = NULL;
290 			break;
291 
292 		  case CMDDATA:		/* data -- text of mail */
293 			SmtpPhase = "DATA";
294 			if (!hasmail)
295 			{
296 				message("503", "Need MAIL command");
297 				break;
298 			}
299 			else if (CurEnv->e_nrcpts <= 0)
300 			{
301 				message("503", "Need RCPT (recipient)");
302 				break;
303 			}
304 
305 			/* collect the text of the message */
306 			SmtpPhase = "collect";
307 			setproctitle("%s %s: %s", CurEnv->e_id,
308 				CurHostName, inp);
309 			collect(TRUE);
310 			if (Errors != 0)
311 				break;
312 
313 			/*
314 			**  Arrange to send to everyone.
315 			**	If sending to multiple people, mail back
316 			**		errors rather than reporting directly.
317 			**	In any case, don't mail back errors for
318 			**		anything that has happened up to
319 			**		now (the other end will do this).
320 			**	Truncate our transcript -- the mail has gotten
321 			**		to us successfully, and if we have
322 			**		to mail this back, it will be easier
323 			**		on the reader.
324 			**	Then send to everyone.
325 			**	Finally give a reply code.  If an error has
326 			**		already been given, don't mail a
327 			**		message back.
328 			**	We goose error returns by clearing error bit.
329 			*/
330 
331 			SmtpPhase = "delivery";
332 			if (CurEnv->e_nrcpts != 1)
333 			{
334 				HoldErrs = TRUE;
335 				ErrorMode = EM_MAIL;
336 			}
337 			CurEnv->e_flags &= ~EF_FATALERRS;
338 			CurEnv->e_xfp = freopen(queuename(CurEnv, 'x'), "w", CurEnv->e_xfp);
339 
340 			/* send to all recipients */
341 			sendall(CurEnv, SM_DEFAULT);
342 			CurEnv->e_to = NULL;
343 
344 			/* save statistics */
345 			markstats(CurEnv, (ADDRESS *) NULL);
346 
347 			/* issue success if appropriate and reset */
348 			if (Errors == 0 || HoldErrs)
349 				message("250", "Ok");
350 			else
351 				CurEnv->e_flags &= ~EF_FATALERRS;
352 
353 			/* if in a child, pop back to our parent */
354 			if (InChild)
355 				finis();
356 
357 			/* clean up a bit */
358 			hasmail = 0;
359 			dropenvelope(CurEnv);
360 			CurEnv = newenvelope(CurEnv);
361 			CurEnv->e_flags = BlankEnvelope.e_flags;
362 			break;
363 
364 		  case CMDRSET:		/* rset -- reset state */
365 			message("250", "Reset state");
366 			if (InChild)
367 				finis();
368 			break;
369 
370 		  case CMDVRFY:		/* vrfy -- verify address */
371 			if (runinchild("SMTP-VRFY") > 0)
372 				break;
373 			setproctitle("%s: %s", CurHostName, inp);
374 			vrfyqueue = NULL;
375 			QuickAbort = TRUE;
376 			sendtolist(p, (ADDRESS *) NULL, &vrfyqueue);
377 			if (Errors != 0)
378 			{
379 				if (InChild)
380 					finis();
381 				break;
382 			}
383 			while (vrfyqueue != NULL)
384 			{
385 				register ADDRESS *a = vrfyqueue->q_next;
386 				char *code;
387 
388 				while (a != NULL && bitset(QDONTSEND|QBADADDR, a->q_flags))
389 					a = a->q_next;
390 
391 				if (!bitset(QDONTSEND|QBADADDR, vrfyqueue->q_flags))
392 				{
393 					if (a != NULL)
394 						code = "250-";
395 					else
396 						code = "250";
397 					if (vrfyqueue->q_fullname == NULL)
398 						message(code, "<%s>", vrfyqueue->q_paddr);
399 					else
400 						message(code, "%s <%s>",
401 						    vrfyqueue->q_fullname, vrfyqueue->q_paddr);
402 				}
403 				else if (a == NULL)
404 					message("554", "Self destructive alias loop");
405 				vrfyqueue = a;
406 			}
407 			if (InChild)
408 				finis();
409 			break;
410 
411 		  case CMDHELP:		/* help -- give user info */
412 			if (*p == '\0')
413 				p = "SMTP";
414 			help(p);
415 			break;
416 
417 		  case CMDNOOP:		/* noop -- do nothing */
418 			message("200", "OK");
419 			break;
420 
421 		  case CMDQUIT:		/* quit -- leave mail */
422 			message("221", "%s closing connection", MyHostName);
423 			if (InChild)
424 				ExitStat = EX_QUIT;
425 			finis();
426 
427 		  case CMDVERB:		/* set verbose mode */
428 			Verbose = TRUE;
429 			SendMode = SM_DELIVER;
430 			message("200", "Verbose mode");
431 			break;
432 
433 		  case CMDONEX:		/* doing one transaction only */
434 			OneXact = TRUE;
435 			message("200", "Only one transaction");
436 			break;
437 
438 # ifdef DEBUG
439 		  case CMDDBGQSHOW:	/* show queues */
440 			printf("Send Queue=");
441 			printaddr(CurEnv->e_sendqueue, TRUE);
442 			break;
443 
444 		  case CMDDBGDEBUG:	/* set debug mode */
445 			tTsetup(tTdvect, sizeof tTdvect, "0-99.1");
446 			tTflag(p);
447 			message("200", "Debug set");
448 			break;
449 # endif DEBUG
450 
451 # ifdef WIZ
452 		  case CMDDBGKILL:	/* kill the parent */
453 			if (!iswiz())
454 				break;
455 			if (kill(MotherPid, SIGTERM) >= 0)
456 				message("200", "Mother is dead");
457 			else
458 				message("500", "Can't kill Mom");
459 			break;
460 
461 		  case CMDDBGWIZ:	/* become a wizard */
462 			if (WizWord != NULL)
463 			{
464 				char seed[3];
465 				extern char *crypt();
466 
467 				(void) strncpy(seed, WizWord, 2);
468 				if (strcmp(WizWord, crypt(p, seed)) == 0)
469 				{
470 					IsWiz = TRUE;
471 					message("200", "Please pass, oh mighty wizard");
472 					break;
473 				}
474 			}
475 			message("500", "You are no wizard!");
476 			break;
477 
478 # else WIZ
479 		  case CMDDBGWIZ:	/* try to become a wizard */
480 			message("500", "You wascal wabbit!  Wandering wizards won't win!");
481 			break;
482 # endif WIZ
483 
484 		  case CMDERROR:	/* unknown command */
485 			message("500", "Command unrecognized");
486 			break;
487 
488 		  default:
489 			syserr("smtp: unknown code %d", c->cmdcode);
490 			break;
491 		}
492 	}
493 }
494 /*
495 **  SKIPWORD -- skip a fixed word.
496 **
497 **	Parameters:
498 **		p -- place to start looking.
499 **		w -- word to skip.
500 **
501 **	Returns:
502 **		p following w.
503 **		NULL on error.
504 **
505 **	Side Effects:
506 **		clobbers the p data area.
507 */
508 
509 static char *
510 skipword(p, w)
511 	register char *p;
512 	char *w;
513 {
514 	register char *q;
515 
516 	/* find beginning of word */
517 	while (isspace(*p))
518 		p++;
519 	q = p;
520 
521 	/* find end of word */
522 	while (*p != '\0' && *p != ':' && !isspace(*p))
523 		p++;
524 	while (isspace(*p))
525 		*p++ = '\0';
526 	if (*p != ':')
527 	{
528 	  syntax:
529 		message("501", "Syntax error");
530 		Errors++;
531 		return (NULL);
532 	}
533 	*p++ = '\0';
534 	while (isspace(*p))
535 		p++;
536 
537 	/* see if the input word matches desired word */
538 	if (strcasecmp(q, w))
539 		goto syntax;
540 
541 	return (p);
542 }
543 /*
544 **  HELP -- implement the HELP command.
545 **
546 **	Parameters:
547 **		topic -- the topic we want help for.
548 **
549 **	Returns:
550 **		none.
551 **
552 **	Side Effects:
553 **		outputs the help file to message output.
554 */
555 
556 help(topic)
557 	char *topic;
558 {
559 	register FILE *hf;
560 	int len;
561 	char buf[MAXLINE];
562 	bool noinfo;
563 
564 	if (HelpFile == NULL || (hf = fopen(HelpFile, "r")) == NULL)
565 	{
566 		/* no help */
567 		errno = 0;
568 		message("502", "HELP not implemented");
569 		return;
570 	}
571 
572 	len = strlen(topic);
573 	makelower(topic);
574 	noinfo = TRUE;
575 
576 	while (fgets(buf, sizeof buf, hf) != NULL)
577 	{
578 		if (strncmp(buf, topic, len) == 0)
579 		{
580 			register char *p;
581 
582 			p = index(buf, '\t');
583 			if (p == NULL)
584 				p = buf;
585 			else
586 				p++;
587 			fixcrlf(p, TRUE);
588 			message("214-", p);
589 			noinfo = FALSE;
590 		}
591 	}
592 
593 	if (noinfo)
594 		message("504", "HELP topic unknown");
595 	else
596 		message("214", "End of HELP info");
597 	(void) fclose(hf);
598 }
599 /*
600 **  ISWIZ -- tell us if we are a wizard
601 **
602 **	If not, print a nasty message.
603 **
604 **	Parameters:
605 **		none.
606 **
607 **	Returns:
608 **		TRUE if we are a wizard.
609 **		FALSE if we are not a wizard.
610 **
611 **	Side Effects:
612 **		Prints a 500 exit stat if we are not a wizard.
613 */
614 
615 #ifdef WIZ
616 
617 bool
618 iswiz()
619 {
620 	if (!IsWiz)
621 		message("500", "Mere mortals musn't mutter that mantra");
622 	return (IsWiz);
623 }
624 
625 #endif WIZ
626 /*
627 **  RUNINCHILD -- return twice -- once in the child, then in the parent again
628 **
629 **	Parameters:
630 **		label -- a string used in error messages
631 **
632 **	Returns:
633 **		zero in the child
634 **		one in the parent
635 **
636 **	Side Effects:
637 **		none.
638 */
639 
640 runinchild(label)
641 	char *label;
642 {
643 	int childpid;
644 
645 	if (!OneXact)
646 	{
647 		childpid = dofork();
648 		if (childpid < 0)
649 		{
650 			syserr("%s: cannot fork", label);
651 			return (1);
652 		}
653 		if (childpid > 0)
654 		{
655 			auto int st;
656 
657 			/* parent -- wait for child to complete */
658 			st = waitfor(childpid);
659 			if (st == -1)
660 				syserr("%s: lost child", label);
661 
662 			/* if we exited on a QUIT command, complete the process */
663 			if (st == (EX_QUIT << 8))
664 				finis();
665 
666 			return (1);
667 		}
668 		else
669 		{
670 			/* child */
671 			InChild = TRUE;
672 			QuickAbort = FALSE;
673 			clearenvelope(CurEnv, FALSE);
674 		}
675 	}
676 
677 	/* open alias database */
678 	initaliases(AliasFile, FALSE);
679 
680 	return (0);
681 }
682 
683 # endif SMTP
684