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	5.15 (Berkeley) 09/23/85	(no SMTP)";
19 # endif not lint
20 # else SMTP
21 
22 # ifndef lint
23 static char	SccsId[] = "@(#)srvrsmtp.c	5.15 (Berkeley) 09/23/85";
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 		setproctitle("srvrsmtp %s", RealHostName);
129 	expand("\001e", inp, &inp[sizeof inp], CurEnv);
130 	message("220", inp);
131 	SmtpPhase = "startup";
132 	for (;;)
133 	{
134 		/* arrange for backout */
135 		if (setjmp(TopFrame) > 0 && InChild)
136 			finis();
137 		QuickAbort = FALSE;
138 		HoldErrs = FALSE;
139 
140 		/* setup for the read */
141 		CurEnv->e_to = NULL;
142 		Errors = 0;
143 		(void) fflush(stdout);
144 
145 		/* read the input line */
146 		p = sfgets(inp, sizeof inp, InChannel);
147 
148 		/* handle errors */
149 		if (p == NULL)
150 		{
151 			/* end of file, just die */
152 			message("421", "%s Lost input channel", HostName);
153 			finis();
154 		}
155 
156 		/* clean up end of line */
157 		fixcrlf(inp, TRUE);
158 
159 		/* echo command to transcript */
160 		if (CurEnv->e_xfp != NULL)
161 			fprintf(CurEnv->e_xfp, "<<< %s\n", inp);
162 
163 		/* break off command */
164 		for (p = inp; isspace(*p); p++)
165 			continue;
166 		cmd = p;
167 		for (cmd = cmdbuf; *p != '\0' && !isspace(*p); )
168 			*cmd++ = *p++;
169 		*cmd = '\0';
170 
171 		/* decode command */
172 		for (c = CmdTab; c->cmdname != NULL; c++)
173 		{
174 			if (sameword(c->cmdname, cmdbuf))
175 				break;
176 		}
177 
178 		/* process command */
179 		switch (c->cmdcode)
180 		{
181 		  case CMDHELO:		/* hello -- introduce yourself */
182 			SmtpPhase = "HELO";
183 			setproctitle("%s: %s", RealHostName, inp);
184 			if (sameword(p, HostName))
185 			{
186 				/* connected to an echo server */
187 				message("553", "%s I refuse to talk to myself",
188 					HostName);
189 				break;
190 			}
191 			if (RealHostName != NULL && !sameword(p, RealHostName))
192 			{
193 				char hostbuf[MAXNAME];
194 
195 				(void) sprintf(hostbuf, "%s (%s)", p, RealHostName);
196 				define('s', newstr(hostbuf), CurEnv);
197 			}
198 			else
199 				define('s', newstr(p), CurEnv);
200 			message("250", "%s Hello %s, pleased to meet you",
201 				HostName, p);
202 			break;
203 
204 		  case CMDMAIL:		/* mail -- designate sender */
205 			SmtpPhase = "MAIL";
206 
207 			/* force a sending host even if no HELO given */
208 			if (RealHostName != NULL && macvalue('s', CurEnv) == NULL)
209 				define('s', RealHostName, CurEnv);
210 
211 			/* check for validity of this command */
212 			if (hasmail)
213 			{
214 				message("503", "Sender already specified");
215 				break;
216 			}
217 			if (InChild)
218 			{
219 				syserr("Nested MAIL command");
220 				exit(0);
221 			}
222 
223 			/* fork a subprocess to process this command */
224 			if (runinchild("SMTP-MAIL") > 0)
225 				break;
226 			initsys();
227 			setproctitle("%s %s: %s", CurEnv->e_id,
228 				RealHostName, inp);
229 
230 			/* child -- go do the processing */
231 			p = skipword(p, "from");
232 			if (p == NULL)
233 				break;
234 			setsender(p);
235 			if (Errors == 0)
236 			{
237 				message("250", "Sender ok");
238 				hasmail = TRUE;
239 			}
240 			else if (InChild)
241 				finis();
242 			break;
243 
244 		  case CMDRCPT:		/* rcpt -- designate recipient */
245 			SmtpPhase = "RCPT";
246 			setproctitle("%s %s: %s", CurEnv->e_id,
247 				RealHostName, inp);
248 			if (setjmp(TopFrame) > 0)
249 			{
250 				CurEnv->e_flags &= ~EF_FATALERRS;
251 				break;
252 			}
253 			QuickAbort = TRUE;
254 			p = skipword(p, "to");
255 			if (p == NULL)
256 				break;
257 			a = parseaddr(p, (ADDRESS *) NULL, 1, '\0');
258 			if (a == NULL)
259 				break;
260 			a->q_flags |= QPRIMARY;
261 			a = recipient(a, &CurEnv->e_sendqueue);
262 			if (Errors != 0)
263 				break;
264 
265 			/* no errors during parsing, but might be a duplicate */
266 			CurEnv->e_to = p;
267 			if (!bitset(QBADADDR, a->q_flags))
268 				message("250", "Recipient ok");
269 			else
270 			{
271 				/* punt -- should keep message in ADDRESS.... */
272 				message("550", "Addressee unknown");
273 			}
274 			CurEnv->e_to = NULL;
275 			break;
276 
277 		  case CMDDATA:		/* data -- text of mail */
278 			SmtpPhase = "DATA";
279 			if (!hasmail)
280 			{
281 				message("503", "Need MAIL command");
282 				break;
283 			}
284 			else if (CurEnv->e_nrcpts <= 0)
285 			{
286 				message("503", "Need RCPT (recipient)");
287 				break;
288 			}
289 
290 			/* collect the text of the message */
291 			SmtpPhase = "collect";
292 			setproctitle("%s %s: %s", CurEnv->e_id,
293 				RealHostName, inp);
294 			collect(TRUE);
295 			if (Errors != 0)
296 				break;
297 
298 			/*
299 			**  Arrange to send to everyone.
300 			**	If sending to multiple people, mail back
301 			**		errors rather than reporting directly.
302 			**	In any case, don't mail back errors for
303 			**		anything that has happened up to
304 			**		now (the other end will do this).
305 			**	Truncate our transcript -- the mail has gotten
306 			**		to us successfully, and if we have
307 			**		to mail this back, it will be easier
308 			**		on the reader.
309 			**	Then send to everyone.
310 			**	Finally give a reply code.  If an error has
311 			**		already been given, don't mail a
312 			**		message back.
313 			**	We goose error returns by clearing error bit.
314 			*/
315 
316 			SmtpPhase = "delivery";
317 			if (CurEnv->e_nrcpts != 1)
318 			{
319 				HoldErrs = TRUE;
320 				ErrorMode = EM_MAIL;
321 			}
322 			CurEnv->e_flags &= ~EF_FATALERRS;
323 			CurEnv->e_xfp = freopen(queuename(CurEnv, 'x'), "w", CurEnv->e_xfp);
324 
325 			/* send to all recipients */
326 			sendall(CurEnv, SM_DEFAULT);
327 			CurEnv->e_to = NULL;
328 
329 			/* save statistics */
330 			markstats(CurEnv, (ADDRESS *) NULL);
331 
332 			/* issue success if appropriate and reset */
333 			if (Errors == 0 || HoldErrs)
334 				message("250", "Ok");
335 			else
336 				CurEnv->e_flags &= ~EF_FATALERRS;
337 
338 			/* if in a child, pop back to our parent */
339 			if (InChild)
340 				finis();
341 
342 			/* clean up a bit */
343 			hasmail = 0;
344 			dropenvelope(CurEnv);
345 			CurEnv = newenvelope(CurEnv);
346 			CurEnv->e_flags = BlankEnvelope.e_flags;
347 			break;
348 
349 		  case CMDRSET:		/* rset -- reset state */
350 			message("250", "Reset state");
351 			if (InChild)
352 				finis();
353 			break;
354 
355 		  case CMDVRFY:		/* vrfy -- verify address */
356 			if (runinchild("SMTP-VRFY") > 0)
357 				break;
358 			setproctitle("%s: %s", RealHostName, inp);
359 			vrfyqueue = NULL;
360 			QuickAbort = TRUE;
361 			sendtolist(p, (ADDRESS *) NULL, &vrfyqueue);
362 			if (Errors != 0)
363 			{
364 				if (InChild)
365 					finis();
366 				break;
367 			}
368 			while (vrfyqueue != NULL)
369 			{
370 				register ADDRESS *a = vrfyqueue->q_next;
371 				char *code;
372 
373 				while (a != NULL && bitset(QDONTSEND|QBADADDR, a->q_flags))
374 					a = a->q_next;
375 
376 				if (!bitset(QDONTSEND|QBADADDR, vrfyqueue->q_flags))
377 				{
378 					if (a != NULL)
379 						code = "250-";
380 					else
381 						code = "250";
382 					if (vrfyqueue->q_fullname == NULL)
383 						message(code, "<%s>", vrfyqueue->q_paddr);
384 					else
385 						message(code, "%s <%s>",
386 						    vrfyqueue->q_fullname, vrfyqueue->q_paddr);
387 				}
388 				else if (a == NULL)
389 					message("554", "Self destructive alias loop");
390 				vrfyqueue = a;
391 			}
392 			if (InChild)
393 				finis();
394 			break;
395 
396 		  case CMDHELP:		/* help -- give user info */
397 			if (*p == '\0')
398 				p = "SMTP";
399 			help(p);
400 			break;
401 
402 		  case CMDNOOP:		/* noop -- do nothing */
403 			message("200", "OK");
404 			break;
405 
406 		  case CMDQUIT:		/* quit -- leave mail */
407 			message("221", "%s closing connection", HostName);
408 			if (InChild)
409 				ExitStat = EX_QUIT;
410 			finis();
411 
412 		  case CMDVERB:		/* set verbose mode */
413 			Verbose = TRUE;
414 			SendMode = SM_DELIVER;
415 			message("200", "Verbose mode");
416 			break;
417 
418 		  case CMDONEX:		/* doing one transaction only */
419 			OneXact = TRUE;
420 			message("200", "Only one transaction");
421 			break;
422 
423 # ifdef DEBUG
424 		  case CMDDBGQSHOW:	/* show queues */
425 			printf("Send Queue=");
426 			printaddr(CurEnv->e_sendqueue, TRUE);
427 			break;
428 
429 		  case CMDDBGDEBUG:	/* set debug mode */
430 			tTsetup(tTdvect, sizeof tTdvect, "0-99.1");
431 			tTflag(p);
432 			message("200", "Debug set");
433 			break;
434 # endif DEBUG
435 
436 # ifdef WIZ
437 		  case CMDDBGKILL:	/* kill the parent */
438 			if (!iswiz())
439 				break;
440 			if (kill(MotherPid, SIGTERM) >= 0)
441 				message("200", "Mother is dead");
442 			else
443 				message("500", "Can't kill Mom");
444 			break;
445 
446 		  case CMDDBGWIZ:	/* become a wizard */
447 			if (WizWord != NULL)
448 			{
449 				char seed[3];
450 				extern char *crypt();
451 
452 				(void) strncpy(seed, WizWord, 2);
453 				if (strcmp(WizWord, crypt(p, seed)) == 0)
454 				{
455 					IsWiz = TRUE;
456 					message("200", "Please pass, oh mighty wizard");
457 					break;
458 				}
459 			}
460 			message("500", "You are no wizard!");
461 			break;
462 
463 # else WIZ
464 		  case CMDDBGWIZ:	/* try to become a wizard */
465 			message("500", "You wascal wabbit!  Wandering wizards won't win!");
466 			break;
467 # endif WIZ
468 
469 		  case CMDERROR:	/* unknown command */
470 			message("500", "Command unrecognized");
471 			break;
472 
473 		  default:
474 			syserr("smtp: unknown code %d", c->cmdcode);
475 			break;
476 		}
477 	}
478 }
479 /*
480 **  SKIPWORD -- skip a fixed word.
481 **
482 **	Parameters:
483 **		p -- place to start looking.
484 **		w -- word to skip.
485 **
486 **	Returns:
487 **		p following w.
488 **		NULL on error.
489 **
490 **	Side Effects:
491 **		clobbers the p data area.
492 */
493 
494 static char *
495 skipword(p, w)
496 	register char *p;
497 	char *w;
498 {
499 	register char *q;
500 	extern bool sameword();
501 
502 	/* find beginning of word */
503 	while (isspace(*p))
504 		p++;
505 	q = p;
506 
507 	/* find end of word */
508 	while (*p != '\0' && *p != ':' && !isspace(*p))
509 		p++;
510 	while (isspace(*p))
511 		*p++ = '\0';
512 	if (*p != ':')
513 	{
514 	  syntax:
515 		message("501", "Syntax error");
516 		Errors++;
517 		return (NULL);
518 	}
519 	*p++ = '\0';
520 	while (isspace(*p))
521 		p++;
522 
523 	/* see if the input word matches desired word */
524 	if (!sameword(q, w))
525 		goto syntax;
526 
527 	return (p);
528 }
529 /*
530 **  HELP -- implement the HELP command.
531 **
532 **	Parameters:
533 **		topic -- the topic we want help for.
534 **
535 **	Returns:
536 **		none.
537 **
538 **	Side Effects:
539 **		outputs the help file to message output.
540 */
541 
542 help(topic)
543 	char *topic;
544 {
545 	register FILE *hf;
546 	int len;
547 	char buf[MAXLINE];
548 	bool noinfo;
549 
550 	if (HelpFile == NULL || (hf = fopen(HelpFile, "r")) == NULL)
551 	{
552 		/* no help */
553 		errno = 0;
554 		message("502", "HELP not implemented");
555 		return;
556 	}
557 
558 	len = strlen(topic);
559 	makelower(topic);
560 	noinfo = TRUE;
561 
562 	while (fgets(buf, sizeof buf, hf) != NULL)
563 	{
564 		if (strncmp(buf, topic, len) == 0)
565 		{
566 			register char *p;
567 
568 			p = index(buf, '\t');
569 			if (p == NULL)
570 				p = buf;
571 			else
572 				p++;
573 			fixcrlf(p, TRUE);
574 			message("214-", p);
575 			noinfo = FALSE;
576 		}
577 	}
578 
579 	if (noinfo)
580 		message("504", "HELP topic unknown");
581 	else
582 		message("214", "End of HELP info");
583 	(void) fclose(hf);
584 }
585 /*
586 **  ISWIZ -- tell us if we are a wizard
587 **
588 **	If not, print a nasty message.
589 **
590 **	Parameters:
591 **		none.
592 **
593 **	Returns:
594 **		TRUE if we are a wizard.
595 **		FALSE if we are not a wizard.
596 **
597 **	Side Effects:
598 **		Prints a 500 exit stat if we are not a wizard.
599 */
600 
601 #ifdef WIZ
602 
603 bool
604 iswiz()
605 {
606 	if (!IsWiz)
607 		message("500", "Mere mortals musn't mutter that mantra");
608 	return (IsWiz);
609 }
610 
611 #endif WIZ
612 /*
613 **  RUNINCHILD -- return twice -- once in the child, then in the parent again
614 **
615 **	Parameters:
616 **		label -- a string used in error messages
617 **
618 **	Returns:
619 **		zero in the child
620 **		one in the parent
621 **
622 **	Side Effects:
623 **		none.
624 */
625 
626 runinchild(label)
627 	char *label;
628 {
629 	int childpid;
630 
631 	if (!OneXact)
632 	{
633 		childpid = dofork();
634 		if (childpid < 0)
635 		{
636 			syserr("%s: cannot fork", label);
637 			return (1);
638 		}
639 		if (childpid > 0)
640 		{
641 			auto int st;
642 
643 			/* parent -- wait for child to complete */
644 			st = waitfor(childpid);
645 			if (st == -1)
646 				syserr("%s: lost child", label);
647 
648 			/* if we exited on a QUIT command, complete the process */
649 			if (st == (EX_QUIT << 8))
650 				finis();
651 
652 			return (1);
653 		}
654 		else
655 		{
656 			/* child */
657 			InChild = TRUE;
658 			clearenvelope(CurEnv);
659 		}
660 	}
661 
662 	/* open alias database */
663 	initaliases(AliasFile, FALSE);
664 
665 	return (0);
666 }
667 
668 # endif SMTP
669