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	5.8 (Berkeley) 09/19/85	(no SMTP)";
19 # endif not lint
20 # else SMTP
21 
22 # ifndef lint
23 static char	SccsId[] = "@(#)srvrsmtp.c	5.8 (Berkeley) 09/19/85";
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 bool	IsWiz = FALSE;			/* set if we are a wizard */
90 char	*WizWord;			/* the wizard word to compare against */
91 bool	InChild = FALSE;		/* true if running in a subprocess */
92 bool	OneXact = FALSE;		/* one xaction only this run */
93 
94 #define EX_QUIT		22		/* special code for QUIT command */
95 
96 smtp()
97 {
98 	register char *p;
99 	register struct cmd *c;
100 	char *cmd;
101 	extern char *skipword();
102 	extern bool sameword();
103 	bool hasmail;			/* mail command received */
104 	int rcps;			/* number of recipients */
105 	auto ADDRESS *vrfyqueue;
106 	ADDRESS *a;
107 	char inp[MAXLINE];
108 	extern char Version[];
109 	extern tick();
110 	extern bool iswiz();
111 	extern char *arpadate();
112 	extern char *macvalue();
113 	extern ADDRESS *recipient();
114 	extern ENVELOPE BlankEnvelope;
115 	extern ENVELOPE *newenvelope();
116 
117 	hasmail = FALSE;
118 	rcps = 0;
119 	if (OutChannel != stdout)
120 	{
121 		/* arrange for debugging output to go to remote host */
122 		(void) close(1);
123 		(void) dup(fileno(OutChannel));
124 	}
125 	settime();
126 	expand("\001e", inp, &inp[sizeof inp], CurEnv);
127 	message("220", inp);
128 	SmtpPhase = "startup";
129 	for (;;)
130 	{
131 		/* arrange for backout */
132 		if (setjmp(TopFrame) > 0 && InChild)
133 			finis();
134 		QuickAbort = FALSE;
135 		HoldErrs = FALSE;
136 
137 		/* setup for the read */
138 		CurEnv->e_to = NULL;
139 		Errors = 0;
140 		(void) fflush(stdout);
141 
142 		/* read the input line */
143 		p = sfgets(inp, sizeof inp, InChannel);
144 
145 		/* handle errors */
146 		if (p == NULL)
147 		{
148 			/* end of file, just die */
149 			message("421", "%s Lost input channel", HostName);
150 			finis();
151 		}
152 
153 		/* clean up end of line */
154 		fixcrlf(inp, TRUE);
155 
156 		/* echo command to transcript */
157 		if (CurEnv->e_xfp != NULL)
158 			fprintf(CurEnv->e_xfp, "<<< %s\n", inp);
159 
160 		/* break off command */
161 		for (p = inp; isspace(*p); p++)
162 			continue;
163 		cmd = p;
164 		while (*++p != '\0' && !isspace(*p))
165 			continue;
166 		if (*p != '\0')
167 			*p++ = '\0';
168 
169 		/* decode command */
170 		for (c = CmdTab; c->cmdname != NULL; c++)
171 		{
172 			if (sameword(c->cmdname, cmd))
173 				break;
174 		}
175 
176 		/* process command */
177 		switch (c->cmdcode)
178 		{
179 		  case CMDHELO:		/* hello -- introduce yourself */
180 			SmtpPhase = "HELO";
181 			if (sameword(p, HostName))
182 			{
183 				/* connected to an echo server */
184 				message("553", "%s I refuse to talk to myself",
185 					HostName);
186 				break;
187 			}
188 			if (RealHostName != NULL && !sameword(p, RealHostName))
189 			{
190 				char buf[MAXNAME];
191 
192 				(void) sprintf(buf, "%s (%s)", p, RealHostName);
193 				define('s', newstr(buf), CurEnv);
194 			}
195 			else
196 				define('s', newstr(p), CurEnv);
197 			message("250", "%s Hello %s, pleased to meet you",
198 				HostName, p);
199 			break;
200 
201 		  case CMDMAIL:		/* mail -- designate sender */
202 			SmtpPhase = "MAIL";
203 
204 			/* force a sending host even if no HELO given */
205 			if (RealHostName != NULL && macvalue('s', CurEnv) == NULL)
206 				define('s', RealHostName, CurEnv);
207 
208 			/* check for validity of this command */
209 			if (hasmail)
210 			{
211 				message("503", "Sender already specified");
212 				break;
213 			}
214 			if (InChild)
215 			{
216 				syserr("Nested MAIL command");
217 				exit(0);
218 			}
219 
220 			/* fork a subprocess to process this command */
221 			if (runinchild("SMTP-MAIL") > 0)
222 				break;
223 			initsys();
224 
225 			/* child -- go do the processing */
226 			p = skipword(p, "from");
227 			if (p == NULL)
228 				break;
229 			setsender(p);
230 			if (Errors == 0)
231 			{
232 				message("250", "Sender ok");
233 				hasmail = TRUE;
234 			}
235 			else if (InChild)
236 				finis();
237 			break;
238 
239 		  case CMDRCPT:		/* rcpt -- designate recipient */
240 			SmtpPhase = "RCPT";
241 			if (setjmp(TopFrame) > 0)
242 			{
243 				CurEnv->e_flags &= ~EF_FATALERRS;
244 				break;
245 			}
246 			QuickAbort = TRUE;
247 			p = skipword(p, "to");
248 			if (p == NULL)
249 				break;
250 			a = parseaddr(p, (ADDRESS *) NULL, 1, '\0');
251 			if (a == NULL)
252 				break;
253 			a->q_flags |= QPRIMARY;
254 			a = recipient(a, &CurEnv->e_sendqueue);
255 			if (Errors != 0)
256 				break;
257 
258 			/* no errors during parsing, but might be a duplicate */
259 			CurEnv->e_to = p;
260 			if (!bitset(QBADADDR, a->q_flags))
261 				message("250", "Recipient ok");
262 			else
263 			{
264 				/* punt -- should keep message in ADDRESS.... */
265 				message("550", "Addressee unknown");
266 			}
267 			CurEnv->e_to = NULL;
268 			rcps++;
269 			break;
270 
271 		  case CMDDATA:		/* data -- text of mail */
272 			SmtpPhase = "DATA";
273 			if (!hasmail)
274 			{
275 				message("503", "Need MAIL command");
276 				break;
277 			}
278 			else if (CurEnv->e_nrcpts <= 0)
279 			{
280 				message("503", "Need RCPT (recipient)");
281 				break;
282 			}
283 
284 			/* collect the text of the message */
285 			SmtpPhase = "collect";
286 			collect(TRUE);
287 			if (Errors != 0)
288 				break;
289 
290 			/*
291 			**  Arrange to send to everyone.
292 			**	If sending to multiple people, mail back
293 			**		errors rather than reporting directly.
294 			**	In any case, don't mail back errors for
295 			**		anything that has happened up to
296 			**		now (the other end will do this).
297 			**	Truncate our transcript -- the mail has gotten
298 			**		to us successfully, and if we have
299 			**		to mail this back, it will be easier
300 			**		on the reader.
301 			**	Then send to everyone.
302 			**	Finally give a reply code.  If an error has
303 			**		already been given, don't mail a
304 			**		message back.
305 			**	We goose error returns by clearing error bit.
306 			*/
307 
308 			SmtpPhase = "delivery";
309 			if (CurEnv->e_nrcpts != 1)
310 			{
311 				HoldErrs = TRUE;
312 				ErrorMode = EM_MAIL;
313 			}
314 			CurEnv->e_flags &= ~EF_FATALERRS;
315 			CurEnv->e_xfp = freopen(queuename(CurEnv, 'x'), "w", CurEnv->e_xfp);
316 
317 			/* send to all recipients */
318 			sendall(CurEnv, SM_DEFAULT);
319 			CurEnv->e_to = NULL;
320 
321 			/* save statistics */
322 			markstats(CurEnv, (ADDRESS *) NULL);
323 
324 			/* issue success if appropriate and reset */
325 			if (Errors == 0 || HoldErrs)
326 				message("250", "Ok");
327 			else
328 				CurEnv->e_flags &= ~EF_FATALERRS;
329 
330 			/* if in a child, pop back to our parent */
331 			if (InChild)
332 				finis();
333 
334 			/* clean up a bit */
335 			hasmail = 0;
336 			rcps = 0;
337 			dropenvelope(CurEnv);
338 			CurEnv = newenvelope(CurEnv);
339 			CurEnv->e_flags = BlankEnvelope.e_flags;
340 			break;
341 
342 		  case CMDRSET:		/* rset -- reset state */
343 			message("250", "Reset state");
344 			if (InChild)
345 				finis();
346 			break;
347 
348 		  case CMDVRFY:		/* vrfy -- verify address */
349 			if (runinchild("SMTP-VRFY") > 0)
350 				break;
351 			vrfyqueue = NULL;
352 			QuickAbort = TRUE;
353 			sendtolist(p, (ADDRESS *) NULL, &vrfyqueue);
354 			if (Errors != 0)
355 			{
356 				if (InChild)
357 					finis();
358 				break;
359 			}
360 			while (vrfyqueue != NULL)
361 			{
362 				register ADDRESS *a = vrfyqueue->q_next;
363 				char *code;
364 
365 				while (a != NULL && bitset(QDONTSEND|QBADADDR, a->q_flags))
366 					a = a->q_next;
367 
368 				if (!bitset(QDONTSEND|QBADADDR, vrfyqueue->q_flags))
369 				{
370 					if (a != NULL)
371 						code = "250-";
372 					else
373 						code = "250";
374 					if (vrfyqueue->q_fullname == NULL)
375 						message(code, "<%s>", vrfyqueue->q_paddr);
376 					else
377 						message(code, "%s <%s>",
378 						    vrfyqueue->q_fullname, vrfyqueue->q_paddr);
379 				}
380 				else if (a == NULL)
381 					message("554", "Self destructive alias loop");
382 				vrfyqueue = a;
383 			}
384 			if (InChild)
385 				finis();
386 			break;
387 
388 		  case CMDHELP:		/* help -- give user info */
389 			if (*p == '\0')
390 				p = "SMTP";
391 			help(p);
392 			break;
393 
394 		  case CMDNOOP:		/* noop -- do nothing */
395 			message("200", "OK");
396 			break;
397 
398 		  case CMDQUIT:		/* quit -- leave mail */
399 			message("221", "%s closing connection", HostName);
400 			if (InChild)
401 				ExitStat = EX_QUIT;
402 			finis();
403 
404 		  case CMDVERB:		/* set verbose mode */
405 			Verbose = TRUE;
406 			message("200", "Verbose mode");
407 			break;
408 
409 		  case CMDONEX:		/* doing one transaction only */
410 			OneXact = TRUE;
411 			message("200", "Only one transaction");
412 			break;
413 
414 # ifdef DEBUG
415 		  case CMDDBGQSHOW:	/* show queues */
416 			printf("Send Queue=");
417 			printaddr(CurEnv->e_sendqueue, TRUE);
418 			break;
419 
420 		  case CMDDBGDEBUG:	/* set debug mode */
421 			tTsetup(tTdvect, sizeof tTdvect, "0-99.1");
422 			tTflag(p);
423 			message("200", "Debug set");
424 			break;
425 # endif DEBUG
426 
427 # ifdef WIZ
428 		  case CMDDBGKILL:	/* kill the parent */
429 			if (!iswiz())
430 				break;
431 			if (kill(MotherPid, SIGTERM) >= 0)
432 				message("200", "Mother is dead");
433 			else
434 				message("500", "Can't kill Mom");
435 			break;
436 
437 		  case CMDDBGWIZ:	/* become a wizard */
438 			if (WizWord != NULL)
439 			{
440 				char seed[3];
441 				extern char *crypt();
442 
443 				(void) strncpy(seed, WizWord, 2);
444 				if (strcmp(WizWord, crypt(p, seed)) == 0)
445 				{
446 					IsWiz = TRUE;
447 					message("200", "Please pass, oh mighty wizard");
448 					break;
449 				}
450 			}
451 			message("500", "You are no wizard!");
452 			break;
453 
454 # else WIZ
455 		  case CMDDBGWIZ:	/* try to become a wizard */
456 			message("500", "You wascal wabbit!  Wandering wizards won't win!");
457 			break;
458 # endif WIZ
459 
460 		  case CMDERROR:	/* unknown command */
461 			message("500", "Command unrecognized");
462 			break;
463 
464 		  default:
465 			syserr("smtp: unknown code %d", c->cmdcode);
466 			break;
467 		}
468 	}
469 }
470 /*
471 **  SKIPWORD -- skip a fixed word.
472 **
473 **	Parameters:
474 **		p -- place to start looking.
475 **		w -- word to skip.
476 **
477 **	Returns:
478 **		p following w.
479 **		NULL on error.
480 **
481 **	Side Effects:
482 **		clobbers the p data area.
483 */
484 
485 static char *
486 skipword(p, w)
487 	register char *p;
488 	char *w;
489 {
490 	register char *q;
491 	extern bool sameword();
492 
493 	/* find beginning of word */
494 	while (isspace(*p))
495 		p++;
496 	q = p;
497 
498 	/* find end of word */
499 	while (*p != '\0' && *p != ':' && !isspace(*p))
500 		p++;
501 	while (isspace(*p))
502 		*p++ = '\0';
503 	if (*p != ':')
504 	{
505 	  syntax:
506 		message("501", "Syntax error");
507 		Errors++;
508 		return (NULL);
509 	}
510 	*p++ = '\0';
511 	while (isspace(*p))
512 		p++;
513 
514 	/* see if the input word matches desired word */
515 	if (!sameword(q, w))
516 		goto syntax;
517 
518 	return (p);
519 }
520 /*
521 **  HELP -- implement the HELP command.
522 **
523 **	Parameters:
524 **		topic -- the topic we want help for.
525 **
526 **	Returns:
527 **		none.
528 **
529 **	Side Effects:
530 **		outputs the help file to message output.
531 */
532 
533 help(topic)
534 	char *topic;
535 {
536 	register FILE *hf;
537 	int len;
538 	char buf[MAXLINE];
539 	bool noinfo;
540 
541 	if (HelpFile == NULL || (hf = fopen(HelpFile, "r")) == NULL)
542 	{
543 		/* no help */
544 		errno = 0;
545 		message("502", "HELP not implemented");
546 		return;
547 	}
548 
549 	len = strlen(topic);
550 	makelower(topic);
551 	noinfo = TRUE;
552 
553 	while (fgets(buf, sizeof buf, hf) != NULL)
554 	{
555 		if (strncmp(buf, topic, len) == 0)
556 		{
557 			register char *p;
558 
559 			p = index(buf, '\t');
560 			if (p == NULL)
561 				p = buf;
562 			else
563 				p++;
564 			fixcrlf(p, TRUE);
565 			message("214-", p);
566 			noinfo = FALSE;
567 		}
568 	}
569 
570 	if (noinfo)
571 		message("504", "HELP topic unknown");
572 	else
573 		message("214", "End of HELP info");
574 	(void) fclose(hf);
575 }
576 /*
577 **  ISWIZ -- tell us if we are a wizard
578 **
579 **	If not, print a nasty message.
580 **
581 **	Parameters:
582 **		none.
583 **
584 **	Returns:
585 **		TRUE if we are a wizard.
586 **		FALSE if we are not a wizard.
587 **
588 **	Side Effects:
589 **		Prints a 500 exit stat if we are not a wizard.
590 */
591 
592 #ifdef WIZ
593 
594 bool
595 iswiz()
596 {
597 	if (!IsWiz)
598 		message("500", "Mere mortals musn't mutter that mantra");
599 	return (IsWiz);
600 }
601 
602 #endif WIZ
603 /*
604 **  RUNINCHILD -- return twice -- once in the child, then in the parent again
605 **
606 **	Parameters:
607 **		label -- a string used in error messages
608 **
609 **	Returns:
610 **		zero in the child
611 **		one in the parent
612 **
613 **	Side Effects:
614 **		none.
615 */
616 
617 runinchild(label)
618 	char *label;
619 {
620 	int childpid;
621 
622 	if (!OneXact)
623 	{
624 		childpid = dofork();
625 		if (childpid < 0)
626 		{
627 			syserr("%s: cannot fork", label);
628 			return (1);
629 		}
630 		if (childpid > 0)
631 		{
632 			auto int st;
633 
634 			/* parent -- wait for child to complete */
635 			st = waitfor(childpid);
636 			if (st == -1)
637 				syserr("%s: lost child", label);
638 
639 			/* if we exited on a QUIT command, complete the process */
640 			if (st == (EX_QUIT << 8))
641 				finis();
642 
643 			return (1);
644 		}
645 		else
646 		{
647 			/* child */
648 			InChild = TRUE;
649 			clearenvelope(CurEnv);
650 		}
651 	}
652 
653 	/* open alias database */
654 	initaliases(AliasFile, FALSE);
655 
656 	return (0);
657 }
658 
659 # endif SMTP
660