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	5.7 (Berkeley) 09/03/85	(no SMTP)";
19 # endif not lint
20 # else SMTP
21 
22 # ifndef lint
23 static char	SccsId[] = "@(#)srvrsmtp.c	5.7 (Berkeley) 09/03/85";
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 char	*RealHostName = NULL;		/* verified hostname, set in daemon.c */
94 
95 #define EX_QUIT		22		/* special code for QUIT command */
96 
97 smtp()
98 {
99 	register char *p;
100 	register struct cmd *c;
101 	char *cmd;
102 	extern char *skipword();
103 	extern bool sameword();
104 	bool hasmail;			/* mail command received */
105 	int rcps;			/* number of recipients */
106 	auto ADDRESS *vrfyqueue;
107 	ADDRESS *a;
108 	char inp[MAXLINE];
109 	extern char Version[];
110 	extern tick();
111 	extern bool iswiz();
112 	extern char *arpadate();
113 	extern char *macvalue();
114 	extern ADDRESS *recipient();
115 
116 	hasmail = FALSE;
117 	rcps = 0;
118 	if (OutChannel != stdout)
119 	{
120 		/* arrange for debugging output to go to remote host */
121 		(void) close(1);
122 		(void) dup(fileno(OutChannel));
123 	}
124 	settime();
125 	expand("\001e", inp, &inp[sizeof inp], CurEnv);
126 	message("220", inp);
127 	for (;;)
128 	{
129 		/* arrange for backout */
130 		if (setjmp(TopFrame) > 0 && InChild)
131 			finis();
132 		QuickAbort = FALSE;
133 		HoldErrs = FALSE;
134 
135 		/* setup for the read */
136 		CurEnv->e_to = NULL;
137 		Errors = 0;
138 		(void) fflush(stdout);
139 
140 		/* read the input line */
141 		p = sfgets(inp, sizeof inp, InChannel);
142 
143 		/* handle errors */
144 		if (p == NULL)
145 		{
146 			/* end of file, just die */
147 			message("421", "%s Lost input channel", HostName);
148 			finis();
149 		}
150 
151 		/* clean up end of line */
152 		fixcrlf(inp, TRUE);
153 
154 		/* echo command to transcript */
155 		if (CurEnv->e_xfp != NULL)
156 			fprintf(CurEnv->e_xfp, "<<< %s\n", inp);
157 
158 		/* break off command */
159 		for (p = inp; isspace(*p); p++)
160 			continue;
161 		cmd = p;
162 		while (*++p != '\0' && !isspace(*p))
163 			continue;
164 		if (*p != '\0')
165 			*p++ = '\0';
166 
167 		/* decode command */
168 		for (c = CmdTab; c->cmdname != NULL; c++)
169 		{
170 			if (sameword(c->cmdname, cmd))
171 				break;
172 		}
173 
174 		/* process command */
175 		switch (c->cmdcode)
176 		{
177 		  case CMDHELO:		/* hello -- introduce yourself */
178 			if (sameword(p, HostName))
179 			{
180 				/* connected to an echo server */
181 				message("553", "%s I refuse to talk to myself",
182 					HostName);
183 				break;
184 			}
185 			if (RealHostName != NULL && !sameword(p, RealHostName))
186 			{
187 				char buf[MAXNAME];
188 
189 				(void) sprintf(buf, "%s (%s)", p, RealHostName);
190 				define('s', newstr(buf), CurEnv);
191 			}
192 			else
193 				define('s', newstr(p), CurEnv);
194 			message("250", "%s Hello %s, pleased to meet you",
195 				HostName, p);
196 			break;
197 
198 		  case CMDMAIL:		/* mail -- designate sender */
199 			/* force a sending host even if no HELO given */
200 			if (RealHostName != NULL && macvalue('s', CurEnv) == NULL)
201 				define('s', RealHostName, CurEnv);
202 
203 			/* check for validity of this command */
204 			if (hasmail)
205 			{
206 				message("503", "Sender already specified");
207 				break;
208 			}
209 			if (InChild)
210 			{
211 				syserr("Nested MAIL command");
212 				exit(0);
213 			}
214 
215 			/* fork a subprocess to process this command */
216 			if (runinchild("SMTP-MAIL") > 0)
217 				break;
218 			initsys();
219 
220 			/* child -- go do the processing */
221 			p = skipword(p, "from");
222 			if (p == NULL)
223 				break;
224 			setsender(p);
225 			if (Errors == 0)
226 			{
227 				message("250", "Sender ok");
228 				hasmail = TRUE;
229 			}
230 			else if (InChild)
231 				finis();
232 			break;
233 
234 		  case CMDRCPT:		/* rcpt -- designate recipient */
235 			if (setjmp(TopFrame) > 0)
236 			{
237 				CurEnv->e_flags &= ~EF_FATALERRS;
238 				break;
239 			}
240 			QuickAbort = TRUE;
241 			p = skipword(p, "to");
242 			if (p == NULL)
243 				break;
244 			a = parseaddr(p, (ADDRESS *) NULL, 1, '\0');
245 			if (a == NULL)
246 				break;
247 			a->q_flags |= QPRIMARY;
248 			a = recipient(a, &CurEnv->e_sendqueue);
249 			if (Errors != 0)
250 				break;
251 
252 			/* no errors during parsing, but might be a duplicate */
253 			CurEnv->e_to = p;
254 			if (!bitset(QBADADDR, a->q_flags))
255 				message("250", "Recipient ok");
256 			else
257 			{
258 				/* punt -- should keep message in ADDRESS.... */
259 				message("550", "Addressee unknown");
260 			}
261 			CurEnv->e_to = NULL;
262 			rcps++;
263 			break;
264 
265 		  case CMDDATA:		/* data -- text of mail */
266 			if (!hasmail)
267 			{
268 				message("503", "Need MAIL command");
269 				break;
270 			}
271 			else if (rcps <= 0)
272 			{
273 				message("503", "Need RCPT (recipient)");
274 				break;
275 			}
276 
277 			/* collect the text of the message */
278 			collect(TRUE);
279 			if (Errors != 0)
280 				break;
281 
282 			/*
283 			**  Arrange to send to everyone.
284 			**	If sending to multiple people, mail back
285 			**		errors rather than reporting directly.
286 			**	In any case, don't mail back errors for
287 			**		anything that has happened up to
288 			**		now (the other end will do this).
289 			**	Truncate our transcript -- the mail has gotten
290 			**		to us successfully, and if we have
291 			**		to mail this back, it will be easier
292 			**		on the reader.
293 			**	Then send to everyone.
294 			**	Finally give a reply code.  If an error has
295 			**		already been given, don't mail a
296 			**		message back.
297 			**	We goose error returns by clearing error bit.
298 			*/
299 
300 			if (rcps != 1)
301 			{
302 				HoldErrs = TRUE;
303 				ErrorMode = EM_MAIL;
304 			}
305 			CurEnv->e_flags &= ~EF_FATALERRS;
306 			CurEnv->e_xfp = freopen(queuename(CurEnv, 'x'), "w", CurEnv->e_xfp);
307 
308 			/* send to all recipients */
309 			sendall(CurEnv, SM_DEFAULT);
310 			CurEnv->e_to = NULL;
311 
312 			/* save statistics */
313 			markstats(CurEnv, (ADDRESS *) NULL);
314 
315 			/* issue success if appropriate and reset */
316 			if (Errors == 0 || HoldErrs)
317 				message("250", "Ok");
318 			else
319 				CurEnv->e_flags &= ~EF_FATALERRS;
320 
321 			/* if in a child, pop back to our parent */
322 			if (InChild)
323 				finis();
324 			break;
325 
326 		  case CMDRSET:		/* rset -- reset state */
327 			message("250", "Reset state");
328 			if (InChild)
329 				finis();
330 			break;
331 
332 		  case CMDVRFY:		/* vrfy -- verify address */
333 			if (runinchild("SMTP-VRFY") > 0)
334 				break;
335 			vrfyqueue = NULL;
336 			QuickAbort = TRUE;
337 			sendtolist(p, (ADDRESS *) NULL, &vrfyqueue);
338 			if (Errors != 0)
339 			{
340 				if (InChild)
341 					finis();
342 				break;
343 			}
344 			while (vrfyqueue != NULL)
345 			{
346 				register ADDRESS *a = vrfyqueue->q_next;
347 				char *code;
348 
349 				while (a != NULL && bitset(QDONTSEND|QBADADDR, a->q_flags))
350 					a = a->q_next;
351 
352 				if (!bitset(QDONTSEND|QBADADDR, vrfyqueue->q_flags))
353 				{
354 					if (a != NULL)
355 						code = "250-";
356 					else
357 						code = "250";
358 					if (vrfyqueue->q_fullname == NULL)
359 						message(code, "<%s>", vrfyqueue->q_paddr);
360 					else
361 						message(code, "%s <%s>",
362 						    vrfyqueue->q_fullname, vrfyqueue->q_paddr);
363 				}
364 				else if (a == NULL)
365 					message("554", "Self destructive alias loop");
366 				vrfyqueue = a;
367 			}
368 			if (InChild)
369 				finis();
370 			break;
371 
372 		  case CMDHELP:		/* help -- give user info */
373 			if (*p == '\0')
374 				p = "SMTP";
375 			help(p);
376 			break;
377 
378 		  case CMDNOOP:		/* noop -- do nothing */
379 			message("200", "OK");
380 			break;
381 
382 		  case CMDQUIT:		/* quit -- leave mail */
383 			message("221", "%s closing connection", HostName);
384 			if (InChild)
385 				ExitStat = EX_QUIT;
386 			finis();
387 
388 		  case CMDVERB:		/* set verbose mode */
389 			Verbose = TRUE;
390 			message("200", "Verbose mode");
391 			break;
392 
393 		  case CMDONEX:		/* doing one transaction only */
394 			OneXact = TRUE;
395 			message("200", "Only one transaction");
396 			break;
397 
398 # ifdef DEBUG
399 		  case CMDDBGQSHOW:	/* show queues */
400 			printf("Send Queue=");
401 			printaddr(CurEnv->e_sendqueue, TRUE);
402 			break;
403 
404 		  case CMDDBGDEBUG:	/* set debug mode */
405 			tTsetup(tTdvect, sizeof tTdvect, "0-99.1");
406 			tTflag(p);
407 			message("200", "Debug set");
408 			break;
409 # endif DEBUG
410 
411 # ifdef WIZ
412 		  case CMDDBGKILL:	/* kill the parent */
413 			if (!iswiz())
414 				break;
415 			if (kill(MotherPid, SIGTERM) >= 0)
416 				message("200", "Mother is dead");
417 			else
418 				message("500", "Can't kill Mom");
419 			break;
420 
421 		  case CMDDBGWIZ:	/* become a wizard */
422 			if (WizWord != NULL)
423 			{
424 				char seed[3];
425 				extern char *crypt();
426 
427 				(void) strncpy(seed, WizWord, 2);
428 				if (strcmp(WizWord, crypt(p, seed)) == 0)
429 				{
430 					IsWiz = TRUE;
431 					message("200", "Please pass, oh mighty wizard");
432 					break;
433 				}
434 			}
435 			message("500", "You are no wizard!");
436 			break;
437 
438 # else WIZ
439 		  case CMDDBGWIZ:	/* try to become a wizard */
440 			message("500", "You wascal wabbit!  Wandering wizards won't win!");
441 			break;
442 # endif WIZ
443 
444 		  case CMDERROR:	/* unknown command */
445 			message("500", "Command unrecognized");
446 			break;
447 
448 		  default:
449 			syserr("smtp: unknown code %d", c->cmdcode);
450 			break;
451 		}
452 	}
453 }
454 /*
455 **  SKIPWORD -- skip a fixed word.
456 **
457 **	Parameters:
458 **		p -- place to start looking.
459 **		w -- word to skip.
460 **
461 **	Returns:
462 **		p following w.
463 **		NULL on error.
464 **
465 **	Side Effects:
466 **		clobbers the p data area.
467 */
468 
469 static char *
470 skipword(p, w)
471 	register char *p;
472 	char *w;
473 {
474 	register char *q;
475 	extern bool sameword();
476 
477 	/* find beginning of word */
478 	while (isspace(*p))
479 		p++;
480 	q = p;
481 
482 	/* find end of word */
483 	while (*p != '\0' && *p != ':' && !isspace(*p))
484 		p++;
485 	while (isspace(*p))
486 		*p++ = '\0';
487 	if (*p != ':')
488 	{
489 	  syntax:
490 		message("501", "Syntax error");
491 		Errors++;
492 		return (NULL);
493 	}
494 	*p++ = '\0';
495 	while (isspace(*p))
496 		p++;
497 
498 	/* see if the input word matches desired word */
499 	if (!sameword(q, w))
500 		goto syntax;
501 
502 	return (p);
503 }
504 /*
505 **  HELP -- implement the HELP command.
506 **
507 **	Parameters:
508 **		topic -- the topic we want help for.
509 **
510 **	Returns:
511 **		none.
512 **
513 **	Side Effects:
514 **		outputs the help file to message output.
515 */
516 
517 help(topic)
518 	char *topic;
519 {
520 	register FILE *hf;
521 	int len;
522 	char buf[MAXLINE];
523 	bool noinfo;
524 
525 	if (HelpFile == NULL || (hf = fopen(HelpFile, "r")) == NULL)
526 	{
527 		/* no help */
528 		errno = 0;
529 		message("502", "HELP not implemented");
530 		return;
531 	}
532 
533 	len = strlen(topic);
534 	makelower(topic);
535 	noinfo = TRUE;
536 
537 	while (fgets(buf, sizeof buf, hf) != NULL)
538 	{
539 		if (strncmp(buf, topic, len) == 0)
540 		{
541 			register char *p;
542 
543 			p = index(buf, '\t');
544 			if (p == NULL)
545 				p = buf;
546 			else
547 				p++;
548 			fixcrlf(p, TRUE);
549 			message("214-", p);
550 			noinfo = FALSE;
551 		}
552 	}
553 
554 	if (noinfo)
555 		message("504", "HELP topic unknown");
556 	else
557 		message("214", "End of HELP info");
558 	(void) fclose(hf);
559 }
560 /*
561 **  ISWIZ -- tell us if we are a wizard
562 **
563 **	If not, print a nasty message.
564 **
565 **	Parameters:
566 **		none.
567 **
568 **	Returns:
569 **		TRUE if we are a wizard.
570 **		FALSE if we are not a wizard.
571 **
572 **	Side Effects:
573 **		Prints a 500 exit stat if we are not a wizard.
574 */
575 
576 #ifdef WIZ
577 
578 bool
579 iswiz()
580 {
581 	if (!IsWiz)
582 		message("500", "Mere mortals musn't mutter that mantra");
583 	return (IsWiz);
584 }
585 
586 #endif WIZ
587 /*
588 **  RUNINCHILD -- return twice -- once in the child, then in the parent again
589 **
590 **	Parameters:
591 **		label -- a string used in error messages
592 **
593 **	Returns:
594 **		zero in the child
595 **		one in the parent
596 **
597 **	Side Effects:
598 **		none.
599 */
600 
601 runinchild(label)
602 	char *label;
603 {
604 	int childpid;
605 
606 	if (!OneXact)
607 	{
608 		childpid = dofork();
609 		if (childpid < 0)
610 		{
611 			syserr("%s: cannot fork", label);
612 			return (1);
613 		}
614 		if (childpid > 0)
615 		{
616 			auto int st;
617 
618 			/* parent -- wait for child to complete */
619 			st = waitfor(childpid);
620 			if (st == -1)
621 				syserr("%s: lost child", label);
622 
623 			/* if we exited on a QUIT command, complete the process */
624 			if (st == (EX_QUIT << 8))
625 				finis();
626 
627 			return (1);
628 		}
629 		else
630 		{
631 			/* child */
632 			InChild = TRUE;
633 			clearenvelope(CurEnv);
634 		}
635 	}
636 
637 	/* open alias database */
638 	initaliases(AliasFile, FALSE);
639 
640 	return (0);
641 }
642 
643 # endif SMTP
644