1 /*
2  * Copyright (c) 1983 Eric P. Allman
3  * Copyright (c) 1988 Regents of the University of California.
4  * All rights reserved.
5  *
6  * %sccs.include.redist.c%
7  */
8 
9 # include "sendmail.h"
10 
11 #ifndef lint
12 #ifdef SMTP
13 static char sccsid[] = "@(#)srvrsmtp.c	6.16 (Berkeley) 02/23/93 (with SMTP)";
14 #else
15 static char sccsid[] = "@(#)srvrsmtp.c	6.16 (Berkeley) 02/23/93 (without SMTP)";
16 #endif
17 #endif /* not lint */
18 
19 # include <errno.h>
20 # include <signal.h>
21 
22 # ifdef SMTP
23 
24 /*
25 **  SMTP -- run the SMTP protocol.
26 **
27 **	Parameters:
28 **		none.
29 **
30 **	Returns:
31 **		never.
32 **
33 **	Side Effects:
34 **		Reads commands from the input channel and processes
35 **			them.
36 */
37 
38 struct cmd
39 {
40 	char	*cmdname;	/* command name */
41 	int	cmdcode;	/* internal code, see below */
42 };
43 
44 /* values for cmdcode */
45 # define CMDERROR	0	/* bad command */
46 # define CMDMAIL	1	/* mail -- designate sender */
47 # define CMDRCPT	2	/* rcpt -- designate recipient */
48 # define CMDDATA	3	/* data -- send message text */
49 # define CMDRSET	4	/* rset -- reset state */
50 # define CMDVRFY	5	/* vrfy -- verify address */
51 # define CMDEXPN	6	/* expn -- expand address */
52 # define CMDNOOP	7	/* noop -- do nothing */
53 # define CMDQUIT	8	/* quit -- close connection and die */
54 # define CMDHELO	9	/* helo -- be polite */
55 # define CMDHELP	10	/* help -- give usage info */
56 /* non-standard commands */
57 # define CMDONEX	16	/* onex -- sending one transaction only */
58 # define CMDVERB	17	/* verb -- go into verbose mode */
59 /* debugging-only commands, only enabled if SMTPDEBUG is defined */
60 # define CMDDBGQSHOW	24	/* showq -- show send queue */
61 # define CMDDBGDEBUG	25	/* debug -- set debug mode */
62 
63 static struct cmd	CmdTab[] =
64 {
65 	"mail",		CMDMAIL,
66 	"rcpt",		CMDRCPT,
67 	"data",		CMDDATA,
68 	"rset",		CMDRSET,
69 	"vrfy",		CMDVRFY,
70 	"expn",		CMDEXPN,
71 	"help",		CMDHELP,
72 	"noop",		CMDNOOP,
73 	"quit",		CMDQUIT,
74 	"helo",		CMDHELO,
75 	"verb",		CMDVERB,
76 	"onex",		CMDONEX,
77 	/*
78 	 * remaining commands are here only
79 	 * to trap and log attempts to use them
80 	 */
81 	"showq",	CMDDBGQSHOW,
82 	"debug",	CMDDBGDEBUG,
83 	NULL,		CMDERROR,
84 };
85 
86 bool	InChild = FALSE;		/* true if running in a subprocess */
87 bool	OneXact = FALSE;		/* one xaction only this run */
88 
89 #define EX_QUIT		22		/* special code for QUIT command */
90 
91 smtp(e)
92 	register ENVELOPE *e;
93 {
94 	register char *p;
95 	register struct cmd *c;
96 	char *cmd;
97 	static char *skipword();
98 	auto ADDRESS *vrfyqueue;
99 	ADDRESS *a;
100 	char *sendinghost;
101 	bool gotmail;			/* mail command received */
102 	bool gothello;			/* helo command received */
103 	bool vrfy;			/* set if this is a vrfy command */
104 	char inp[MAXLINE];
105 	char cmdbuf[MAXLINE];
106 	extern char Version[];
107 	extern char *macvalue();
108 	extern ADDRESS *recipient();
109 	extern ENVELOPE BlankEnvelope;
110 	extern ENVELOPE *newenvelope();
111 
112 	gotmail = FALSE;
113 	if (OutChannel != stdout)
114 	{
115 		/* arrange for debugging output to go to remote host */
116 		(void) close(1);
117 		(void) dup(fileno(OutChannel));
118 	}
119 	settime(e);
120 	if (RealHostName == NULL)
121 		RealHostName = MyHostName;
122 	CurHostName = RealHostName;
123 	setproctitle("srvrsmtp %s", CurHostName);
124 	expand("\201e", inp, &inp[sizeof inp], e);
125 	message("220 %s", inp);
126 	SmtpPhase = "startup";
127 	sendinghost = NULL;
128 	gothello = FALSE;
129 	for (;;)
130 	{
131 		/* arrange for backout */
132 		if (setjmp(TopFrame) > 0 && InChild)
133 			finis();
134 		QuickAbort = FALSE;
135 		HoldErrs = FALSE;
136 		LogUsrErrs = FALSE;
137 		e->e_flags &= ~EF_VRFYONLY;
138 
139 		/* setup for the read */
140 		e->e_to = NULL;
141 		Errors = 0;
142 		(void) fflush(stdout);
143 
144 		/* read the input line */
145 		p = sfgets(inp, sizeof inp, InChannel, TimeOuts.to_nextcommand);
146 
147 		/* handle errors */
148 		if (p == NULL)
149 		{
150 			/* end of file, just die */
151 			message("421 %s Lost input channel from %s",
152 				MyHostName, CurHostName);
153 #ifdef LOG
154 			if (LogLevel > 1)
155 				syslog(LOG_NOTICE, "lost input channel from %s",
156 					CurHostName);
157 #endif
158 			if (InChild)
159 				ExitStat = EX_QUIT;
160 			finis();
161 		}
162 
163 		/* clean up end of line */
164 		fixcrlf(inp, TRUE);
165 
166 		/* echo command to transcript */
167 		if (e->e_xfp != NULL)
168 			fprintf(e->e_xfp, "<<< %s\n", inp);
169 
170 		/* break off command */
171 		for (p = inp; isascii(*p) && isspace(*p); p++)
172 			continue;
173 		cmd = cmdbuf;
174 		while (*p != '\0' &&
175 		       !(isascii(*p) && isspace(*p)) &&
176 		       cmd < &cmdbuf[sizeof cmdbuf - 2])
177 			*cmd++ = *p++;
178 		*cmd = '\0';
179 
180 		/* throw away leading whitespace */
181 		while (isascii(*p) && isspace(*p))
182 			p++;
183 
184 		/* decode command */
185 		for (c = CmdTab; c->cmdname != NULL; c++)
186 		{
187 			if (!strcasecmp(c->cmdname, cmdbuf))
188 				break;
189 		}
190 
191 		/* reset errors */
192 		errno = 0;
193 
194 		/* process command */
195 		switch (c->cmdcode)
196 		{
197 		  case CMDHELO:		/* hello -- introduce yourself */
198 			SmtpPhase = "HELO";
199 			setproctitle("%s: %s", CurHostName, inp);
200 			if (strcasecmp(p, MyHostName) == 0)
201 			{
202 				/*
203 				**  Didn't know about alias or MX,
204 				**  or connected to an echo server
205 				*/
206 
207 				message("553 %s config error: mail loops back to myself",
208 					MyHostName);
209 				break;
210 			}
211 			if (RealHostName != NULL && strcasecmp(p, RealHostName) != 0)
212 			{
213 				char hostbuf[MAXNAME];
214 
215 				(void) sprintf(hostbuf, "%s (%s)", p, RealHostName);
216 				sendinghost = newstr(hostbuf);
217 			}
218 			else
219 				sendinghost = newstr(p);
220 			message("250 %s Hello %s, pleased to meet you",
221 				MyHostName, sendinghost);
222 			gothello = TRUE;
223 			break;
224 
225 		  case CMDMAIL:		/* mail -- designate sender */
226 			SmtpPhase = "MAIL";
227 
228 			/* force a sending host even if no HELO given */
229 			if (sendinghost == NULL && macvalue('s', e) == NULL)
230 				sendinghost = RealHostName;
231 
232 			/* check for validity of this command */
233 			if (!gothello && bitset(PRIV_NEEDMAILHELO, PrivacyFlags))
234 			{
235 				message("503 Polite people say HELO first");
236 				break;
237 			}
238 			if (gotmail)
239 			{
240 				message("503 Sender already specified");
241 				break;
242 			}
243 			if (InChild)
244 			{
245 				errno = 0;
246 				syserr("503 Nested MAIL command: MAIL %s", p);
247 				finis();
248 			}
249 			if (!enoughspace())
250 			{
251 				message("452 Insufficient disk space; try again later");
252 				break;
253 			}
254 
255 			/* fork a subprocess to process this command */
256 			if (runinchild("SMTP-MAIL", e) > 0)
257 				break;
258 			if (sendinghost != NULL)
259 				define('s', sendinghost, e);
260 			define('r', "SMTP", e);
261 			initsys(e);
262 			setproctitle("%s %s: %s", e->e_id, CurHostName, inp);
263 
264 			/* child -- go do the processing */
265 			p = skipword(p, "from");
266 			if (p == NULL)
267 				break;
268 			if (setjmp(TopFrame) > 0)
269 			{
270 				/* this failed -- undo work */
271 				if (InChild)
272 					finis();
273 				break;
274 			}
275 			QuickAbort = TRUE;
276 			setsender(p, e);
277 			message("250 Sender ok");
278 			gotmail = TRUE;
279 			break;
280 
281 		  case CMDRCPT:		/* rcpt -- designate recipient */
282 			SmtpPhase = "RCPT";
283 			setproctitle("%s %s: %s", e->e_id, CurHostName, inp);
284 			if (setjmp(TopFrame) > 0)
285 			{
286 				e->e_flags &= ~EF_FATALERRS;
287 				break;
288 			}
289 			QuickAbort = TRUE;
290 			LogUsrErrs = TRUE;
291 
292 			/* optimization -- if queueing, don't expand aliases */
293 			if (SendMode == SM_QUEUE)
294 				e->e_flags |= EF_VRFYONLY;
295 
296 			p = skipword(p, "to");
297 			if (p == NULL)
298 				break;
299 			a = parseaddr(p, (ADDRESS *) NULL, 1, '\0', e);
300 			if (a == NULL)
301 				break;
302 			a->q_flags |= QPRIMARY;
303 			a = recipient(a, &e->e_sendqueue, e);
304 			if (Errors != 0)
305 				break;
306 
307 			/* no errors during parsing, but might be a duplicate */
308 			e->e_to = p;
309 			if (!bitset(QBADADDR, a->q_flags))
310 				message("250 Recipient ok");
311 			else
312 			{
313 				/* punt -- should keep message in ADDRESS.... */
314 				message("550 Addressee unknown");
315 			}
316 			e->e_to = NULL;
317 			break;
318 
319 		  case CMDDATA:		/* data -- text of mail */
320 			SmtpPhase = "DATA";
321 			if (!gotmail)
322 			{
323 				message("503 Need MAIL command");
324 				break;
325 			}
326 			else if (e->e_nrcpts <= 0)
327 			{
328 				message("503 Need RCPT (recipient)");
329 				break;
330 			}
331 
332 			/* collect the text of the message */
333 			SmtpPhase = "collect";
334 			setproctitle("%s %s: %s", e->e_id, CurHostName, inp);
335 			collect(TRUE, e);
336 			if (Errors != 0)
337 				break;
338 
339 			/*
340 			**  Arrange to send to everyone.
341 			**	If sending to multiple people, mail back
342 			**		errors rather than reporting directly.
343 			**	In any case, don't mail back errors for
344 			**		anything that has happened up to
345 			**		now (the other end will do this).
346 			**	Truncate our transcript -- the mail has gotten
347 			**		to us successfully, and if we have
348 			**		to mail this back, it will be easier
349 			**		on the reader.
350 			**	Then send to everyone.
351 			**	Finally give a reply code.  If an error has
352 			**		already been given, don't mail a
353 			**		message back.
354 			**	We goose error returns by clearing error bit.
355 			*/
356 
357 			SmtpPhase = "delivery";
358 			if (e->e_nrcpts != 1)
359 			{
360 				HoldErrs = TRUE;
361 				ErrorMode = EM_MAIL;
362 			}
363 			e->e_flags &= ~EF_FATALERRS;
364 			e->e_xfp = freopen(queuename(e, 'x'), "w", e->e_xfp);
365 
366 			/* send to all recipients */
367 			sendall(e, SM_DEFAULT);
368 			e->e_to = NULL;
369 
370 			/* save statistics */
371 			markstats(e, (ADDRESS *) NULL);
372 
373 			/* issue success if appropriate and reset */
374 			if (Errors == 0 || HoldErrs)
375 				message("250 Ok");
376 			else
377 				e->e_flags &= ~EF_FATALERRS;
378 
379 			/* if in a child, pop back to our parent */
380 			if (InChild)
381 				finis();
382 
383 			/* clean up a bit */
384 			gotmail = FALSE;
385 			dropenvelope(e);
386 			CurEnv = e = newenvelope(e);
387 			e->e_flags = BlankEnvelope.e_flags;
388 			break;
389 
390 		  case CMDRSET:		/* rset -- reset state */
391 			message("250 Reset state");
392 			if (InChild)
393 				finis();
394 
395 			/* clean up a bit */
396 			gotmail = FALSE;
397 			dropenvelope(e);
398 			CurEnv = e = newenvelope(e);
399 			break;
400 
401 		  case CMDVRFY:		/* vrfy -- verify address */
402 		  case CMDEXPN:		/* expn -- expand address */
403 			vrfy = c->cmdcode == CMDVRFY;
404 			if (bitset(vrfy ? PRIV_NOVRFY : PRIV_NOEXPN,
405 						PrivacyFlags))
406 			{
407 				message("502 That's none of your business");
408 				break;
409 			}
410 			else if (!gothello &&
411 				 bitset(vrfy ? PRIV_NEEDVRFYHELO : PRIV_NEEDEXPNHELO,
412 						PrivacyFlags))
413 			{
414 				message("503 I demand that you introduce yourself first");
415 				break;
416 			}
417 			if (runinchild(vrfy ? "SMTP-VRFY" : "SMTP-EXPN", e) > 0)
418 				break;
419 			setproctitle("%s: %s", CurHostName, inp);
420 #ifdef LOG
421 			if (LogLevel > 5)
422 				syslog(LOG_INFO, "%s: %s", CurHostName, inp);
423 #endif
424 			vrfyqueue = NULL;
425 			QuickAbort = TRUE;
426 			if (vrfy)
427 				e->e_flags |= EF_VRFYONLY;
428 			(void) sendtolist(p, (ADDRESS *) NULL, &vrfyqueue, e);
429 			if (Errors != 0)
430 			{
431 				if (InChild)
432 					finis();
433 				break;
434 			}
435 			while (vrfyqueue != NULL)
436 			{
437 				register ADDRESS *a = vrfyqueue->q_next;
438 				char *code;
439 
440 				while (a != NULL && bitset(QDONTSEND|QBADADDR, a->q_flags))
441 					a = a->q_next;
442 
443 				if (!bitset(QDONTSEND|QBADADDR, vrfyqueue->q_flags))
444 					printvrfyaddr(vrfyqueue, a == NULL);
445 				else if (a == NULL)
446 					message("554 Self destructive alias loop");
447 				vrfyqueue = a;
448 			}
449 			if (InChild)
450 				finis();
451 			break;
452 
453 		  case CMDHELP:		/* help -- give user info */
454 			help(p);
455 			break;
456 
457 		  case CMDNOOP:		/* noop -- do nothing */
458 			message("200 OK");
459 			break;
460 
461 		  case CMDQUIT:		/* quit -- leave mail */
462 			message("221 %s closing connection", MyHostName);
463 			if (InChild)
464 				ExitStat = EX_QUIT;
465 			finis();
466 
467 		  case CMDVERB:		/* set verbose mode */
468 			Verbose = TRUE;
469 			SendMode = SM_DELIVER;
470 			message("200 Verbose mode");
471 			break;
472 
473 		  case CMDONEX:		/* doing one transaction only */
474 			OneXact = TRUE;
475 			message("200 Only one transaction");
476 			break;
477 
478 # ifdef SMTPDEBUG
479 		  case CMDDBGQSHOW:	/* show queues */
480 			printf("Send Queue=");
481 			printaddr(e->e_sendqueue, TRUE);
482 			break;
483 
484 		  case CMDDBGDEBUG:	/* set debug mode */
485 			tTsetup(tTdvect, sizeof tTdvect, "0-99.1");
486 			tTflag(p);
487 			message("200 Debug set");
488 			break;
489 
490 # else /* not SMTPDEBUG */
491 
492 		  case CMDDBGQSHOW:	/* show queues */
493 		  case CMDDBGDEBUG:	/* set debug mode */
494 # ifdef LOG
495 			if (RealHostName != NULL && LogLevel > 0)
496 				syslog(LOG_NOTICE,
497 				    "\"%s\" command from %s (%s)",
498 				    c->cmdname, RealHostName,
499 				    inet_ntoa(RealHostAddr.sin_addr));
500 # endif
501 			/* FALL THROUGH */
502 # endif /* SMTPDEBUG */
503 
504 		  case CMDERROR:	/* unknown command */
505 			message("500 Command unrecognized");
506 			break;
507 
508 		  default:
509 			errno = 0;
510 			syserr("500 smtp: unknown code %d", c->cmdcode);
511 			break;
512 		}
513 	}
514 }
515 /*
516 **  SKIPWORD -- skip a fixed word.
517 **
518 **	Parameters:
519 **		p -- place to start looking.
520 **		w -- word to skip.
521 **
522 **	Returns:
523 **		p following w.
524 **		NULL on error.
525 **
526 **	Side Effects:
527 **		clobbers the p data area.
528 */
529 
530 static char *
531 skipword(p, w)
532 	register char *p;
533 	char *w;
534 {
535 	register char *q;
536 
537 	/* find beginning of word */
538 	while (isascii(*p) && isspace(*p))
539 		p++;
540 	q = p;
541 
542 	/* find end of word */
543 	while (*p != '\0' && *p != ':' && !(isascii(*p) && isspace(*p)))
544 		p++;
545 	while (isascii(*p) && isspace(*p))
546 		*p++ = '\0';
547 	if (*p != ':')
548 	{
549 	  syntax:
550 		message("501 Syntax error");
551 		Errors++;
552 		return (NULL);
553 	}
554 	*p++ = '\0';
555 	while (isascii(*p) && isspace(*p))
556 		p++;
557 
558 	/* see if the input word matches desired word */
559 	if (strcasecmp(q, w))
560 		goto syntax;
561 
562 	return (p);
563 }
564 /*
565 **  PRINTVRFYADDR -- print an entry in the verify queue
566 **
567 **	Parameters:
568 **		a -- the address to print
569 **		last -- set if this is the last one.
570 **
571 **	Returns:
572 **		none.
573 **
574 **	Side Effects:
575 **		Prints the appropriate 250 codes.
576 */
577 
578 printvrfyaddr(a, last)
579 	register ADDRESS *a;
580 	bool last;
581 {
582 	char fmtbuf[20];
583 
584 	strcpy(fmtbuf, "250");
585 	fmtbuf[3] = last ? ' ' : '-';
586 
587 	if (strchr(a->q_paddr, '<') != NULL)
588 		strcpy(&fmtbuf[4], "%s");
589 	else if (a->q_fullname == NULL)
590 		strcpy(&fmtbuf[4], "<%s>");
591 	else
592 	{
593 		strcpy(&fmtbuf[4], "%s <%s>");
594 		message(fmtbuf, a->q_fullname, a->q_paddr);
595 		return;
596 	}
597 	message(fmtbuf, a->q_paddr);
598 }
599 /*
600 **  HELP -- implement the HELP command.
601 **
602 **	Parameters:
603 **		topic -- the topic we want help for.
604 **
605 **	Returns:
606 **		none.
607 **
608 **	Side Effects:
609 **		outputs the help file to message output.
610 */
611 
612 help(topic)
613 	char *topic;
614 {
615 	register FILE *hf;
616 	int len;
617 	char buf[MAXLINE];
618 	bool noinfo;
619 
620 	if (HelpFile == NULL || (hf = fopen(HelpFile, "r")) == NULL)
621 	{
622 		/* no help */
623 		errno = 0;
624 		message("502 HELP not implemented");
625 		return;
626 	}
627 
628 	if (topic == NULL || *topic == '\0')
629 		topic = "smtp";
630 	else
631 		makelower(topic);
632 
633 	len = strlen(topic);
634 	noinfo = TRUE;
635 
636 	while (fgets(buf, sizeof buf, hf) != NULL)
637 	{
638 		if (strncmp(buf, topic, len) == 0)
639 		{
640 			register char *p;
641 
642 			p = strchr(buf, '\t');
643 			if (p == NULL)
644 				p = buf;
645 			else
646 				p++;
647 			fixcrlf(p, TRUE);
648 			message("214-%s", p);
649 			noinfo = FALSE;
650 		}
651 	}
652 
653 	if (noinfo)
654 		message("504 HELP topic unknown");
655 	else
656 		message("214 End of HELP info");
657 	(void) fclose(hf);
658 }
659 /*
660 **  RUNINCHILD -- return twice -- once in the child, then in the parent again
661 **
662 **	Parameters:
663 **		label -- a string used in error messages
664 **
665 **	Returns:
666 **		zero in the child
667 **		one in the parent
668 **
669 **	Side Effects:
670 **		none.
671 */
672 
673 runinchild(label, e)
674 	char *label;
675 	register ENVELOPE *e;
676 {
677 	int childpid;
678 
679 	if (!OneXact)
680 	{
681 		childpid = dofork();
682 		if (childpid < 0)
683 		{
684 			syserr("%s: cannot fork", label);
685 			return (1);
686 		}
687 		if (childpid > 0)
688 		{
689 			auto int st;
690 
691 			/* parent -- wait for child to complete */
692 			st = waitfor(childpid);
693 			if (st == -1)
694 				syserr("%s: lost child", label);
695 
696 			/* if we exited on a QUIT command, complete the process */
697 			if (st == (EX_QUIT << 8))
698 				finis();
699 
700 			return (1);
701 		}
702 		else
703 		{
704 			/* child */
705 			InChild = TRUE;
706 			QuickAbort = FALSE;
707 			clearenvelope(e, FALSE);
708 		}
709 	}
710 
711 	/* open alias database */
712 	initaliases(AliasFile, FALSE, e);
713 
714 	return (0);
715 }
716 
717 # endif /* SMTP */
718