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	6.13 (Berkeley) 02/20/93 (with SMTP)";
14 #else
15 static char sccsid[] = "@(#)srvrsmtp.c	6.13 (Berkeley) 02/20/93 (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 hasmail;			/* 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 	hasmail = 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, ReadTimeout);
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))
201 			{
202 				/*
203 				 * didn't know about alias,
204 				 * or connected to an echo server
205 				 */
206 				message("553", "%s config error: mail loops back to myself",
207 					MyHostName);
208 				break;
209 			}
210 			if (RealHostName != NULL && strcasecmp(p, RealHostName))
211 			{
212 				char hostbuf[MAXNAME];
213 
214 				(void) sprintf(hostbuf, "%s (%s)", p, RealHostName);
215 				sendinghost = newstr(hostbuf);
216 			}
217 			else
218 				sendinghost = newstr(p);
219 			message("250", "%s Hello %s, pleased to meet you",
220 				MyHostName, sendinghost);
221 			gothello = TRUE;
222 			break;
223 
224 		  case CMDMAIL:		/* mail -- designate sender */
225 			SmtpPhase = "MAIL";
226 
227 			/* force a sending host even if no HELO given */
228 			if (sendinghost == NULL && macvalue('s', e) == NULL)
229 				sendinghost = RealHostName;
230 
231 			/* check for validity of this command */
232 			if (!gothello && bitset(PRIV_NEEDMAILHELO, PrivacyFlags))
233 			{
234 				message("503", "Polite people say HELO first");
235 				break;
236 			}
237 			if (hasmail)
238 			{
239 				message("503", "Sender already specified");
240 				break;
241 			}
242 			if (InChild)
243 			{
244 				errno = 0;
245 				syserr("Nested MAIL command: MAIL %s", p);
246 				finis();
247 			}
248 			if (!enoughspace())
249 			{
250 				message("452", "Insufficient disk space; try again later");
251 				break;
252 			}
253 
254 			/* fork a subprocess to process this command */
255 			if (runinchild("SMTP-MAIL", e) > 0)
256 				break;
257 			if (sendinghost != NULL)
258 				define('s', sendinghost, e);
259 			define('r', "SMTP", e);
260 			initsys(e);
261 			setproctitle("%s %s: %s", e->e_id, CurHostName, inp);
262 
263 			/* child -- go do the processing */
264 			p = skipword(p, "from");
265 			if (p == NULL)
266 				break;
267 			if (setjmp(TopFrame) > 0)
268 				break;
269 			QuickAbort = TRUE;
270 			setsender(p, e);
271 			if (Errors == 0)
272 			{
273 				message("250", "Sender ok");
274 				hasmail = TRUE;
275 			}
276 			else if (InChild)
277 				finis();
278 			break;
279 
280 		  case CMDRCPT:		/* rcpt -- designate recipient */
281 			SmtpPhase = "RCPT";
282 			setproctitle("%s %s: %s", e->e_id, CurHostName, inp);
283 			if (setjmp(TopFrame) > 0)
284 			{
285 				e->e_flags &= ~EF_FATALERRS;
286 				break;
287 			}
288 			QuickAbort = TRUE;
289 			LogUsrErrs = TRUE;
290 
291 			/* optimization -- if queueing, don't expand aliases */
292 			if (SendMode == SM_QUEUE)
293 				e->e_flags |= EF_VRFYONLY;
294 
295 			p = skipword(p, "to");
296 			if (p == NULL)
297 				break;
298 			a = parseaddr(p, (ADDRESS *) NULL, 1, '\0', e);
299 			if (a == NULL)
300 				break;
301 			a->q_flags |= QPRIMARY;
302 			a = recipient(a, &e->e_sendqueue, e);
303 			if (Errors != 0)
304 				break;
305 
306 			/* no errors during parsing, but might be a duplicate */
307 			e->e_to = p;
308 			if (!bitset(QBADADDR, a->q_flags))
309 				message("250", "Recipient ok");
310 			else
311 			{
312 				/* punt -- should keep message in ADDRESS.... */
313 				message("550", "Addressee unknown");
314 			}
315 			e->e_to = NULL;
316 			break;
317 
318 		  case CMDDATA:		/* data -- text of mail */
319 			SmtpPhase = "DATA";
320 			if (!hasmail)
321 			{
322 				message("503", "Need MAIL command");
323 				break;
324 			}
325 			else if (e->e_nrcpts <= 0)
326 			{
327 				message("503", "Need RCPT (recipient)");
328 				break;
329 			}
330 
331 			/* collect the text of the message */
332 			SmtpPhase = "collect";
333 			setproctitle("%s %s: %s", e->e_id, CurHostName, inp);
334 			collect(TRUE, e);
335 			if (Errors != 0)
336 				break;
337 
338 			/*
339 			**  Arrange to send to everyone.
340 			**	If sending to multiple people, mail back
341 			**		errors rather than reporting directly.
342 			**	In any case, don't mail back errors for
343 			**		anything that has happened up to
344 			**		now (the other end will do this).
345 			**	Truncate our transcript -- the mail has gotten
346 			**		to us successfully, and if we have
347 			**		to mail this back, it will be easier
348 			**		on the reader.
349 			**	Then send to everyone.
350 			**	Finally give a reply code.  If an error has
351 			**		already been given, don't mail a
352 			**		message back.
353 			**	We goose error returns by clearing error bit.
354 			*/
355 
356 			SmtpPhase = "delivery";
357 			if (e->e_nrcpts != 1)
358 			{
359 				HoldErrs = TRUE;
360 				ErrorMode = EM_MAIL;
361 			}
362 			e->e_flags &= ~EF_FATALERRS;
363 			e->e_xfp = freopen(queuename(e, 'x'), "w", e->e_xfp);
364 
365 			/* send to all recipients */
366 			sendall(e, SM_DEFAULT);
367 			e->e_to = NULL;
368 
369 			/* save statistics */
370 			markstats(e, (ADDRESS *) NULL);
371 
372 			/* issue success if appropriate and reset */
373 			if (Errors == 0 || HoldErrs)
374 				message("250", "Ok");
375 			else
376 				e->e_flags &= ~EF_FATALERRS;
377 
378 			/* if in a child, pop back to our parent */
379 			if (InChild)
380 				finis();
381 
382 			/* clean up a bit */
383 			hasmail = FALSE;
384 			dropenvelope(e);
385 			CurEnv = e = newenvelope(e);
386 			e->e_flags = BlankEnvelope.e_flags;
387 			break;
388 
389 		  case CMDRSET:		/* rset -- reset state */
390 			message("250", "Reset state");
391 			if (InChild)
392 				finis();
393 			break;
394 
395 		  case CMDVRFY:		/* vrfy -- verify address */
396 		  case CMDEXPN:		/* expn -- expand address */
397 			vrfy = c->cmdcode == CMDVRFY;
398 			if (bitset(vrfy ? PRIV_NOVRFY : PRIV_NOEXPN,
399 						PrivacyFlags))
400 			{
401 				message("502", "That's none of your business");
402 				break;
403 			}
404 			else if (!gothello &&
405 				 bitset(vrfy ? PRIV_NEEDVRFYHELO : PRIV_NEEDEXPNHELO,
406 						PrivacyFlags))
407 			{
408 				message("503", "I demand that you introduce yourself first");
409 				break;
410 			}
411 			if (runinchild(vrfy ? "SMTP-VRFY" : "SMTP-EXPN", e) > 0)
412 				break;
413 			setproctitle("%s: %s", CurHostName, inp);
414 #ifdef LOG
415 			if (LogLevel > 5)
416 				syslog(LOG_INFO, "%s: %s", CurHostName, inp);
417 #endif
418 			vrfyqueue = NULL;
419 			QuickAbort = TRUE;
420 			if (vrfy)
421 				e->e_flags |= EF_VRFYONLY;
422 			(void) sendtolist(p, (ADDRESS *) NULL, &vrfyqueue, e);
423 			if (Errors != 0)
424 			{
425 				if (InChild)
426 					finis();
427 				break;
428 			}
429 			while (vrfyqueue != NULL)
430 			{
431 				register ADDRESS *a = vrfyqueue->q_next;
432 				char *code;
433 
434 				while (a != NULL && bitset(QDONTSEND|QBADADDR, a->q_flags))
435 					a = a->q_next;
436 
437 				if (!bitset(QDONTSEND|QBADADDR, vrfyqueue->q_flags))
438 				{
439 					if (a != NULL)
440 						code = "250-";
441 					else
442 						code = "250";
443 					if (strchr(vrfyqueue->q_paddr, '<') != NULL)
444 						message(code, "%s", vrfyqueue->q_paddr);
445 					else if (vrfyqueue->q_fullname == NULL)
446 						message(code, "<%s>", vrfyqueue->q_paddr);
447 					else
448 						message(code, "%s <%s>",
449 						    vrfyqueue->q_fullname, vrfyqueue->q_paddr);
450 				}
451 				else if (a == NULL)
452 					message("554", "Self destructive alias loop");
453 				vrfyqueue = a;
454 			}
455 			if (InChild)
456 				finis();
457 			break;
458 
459 		  case CMDHELP:		/* help -- give user info */
460 			help(p);
461 			break;
462 
463 		  case CMDNOOP:		/* noop -- do nothing */
464 			message("200", "OK");
465 			break;
466 
467 		  case CMDQUIT:		/* quit -- leave mail */
468 			message("221", "%s closing connection", MyHostName);
469 			if (InChild)
470 				ExitStat = EX_QUIT;
471 			finis();
472 
473 		  case CMDVERB:		/* set verbose mode */
474 			Verbose = TRUE;
475 			SendMode = SM_DELIVER;
476 			message("200", "Verbose mode");
477 			break;
478 
479 		  case CMDONEX:		/* doing one transaction only */
480 			OneXact = TRUE;
481 			message("200", "Only one transaction");
482 			break;
483 
484 # ifdef SMTPDEBUG
485 		  case CMDDBGQSHOW:	/* show queues */
486 			printf("Send Queue=");
487 			printaddr(e->e_sendqueue, TRUE);
488 			break;
489 
490 		  case CMDDBGDEBUG:	/* set debug mode */
491 			tTsetup(tTdvect, sizeof tTdvect, "0-99.1");
492 			tTflag(p);
493 			message("200", "Debug set");
494 			break;
495 
496 # else /* not SMTPDEBUG */
497 
498 		  case CMDDBGQSHOW:	/* show queues */
499 		  case CMDDBGDEBUG:	/* set debug mode */
500 # ifdef LOG
501 			if (RealHostName != NULL && LogLevel > 0)
502 				syslog(LOG_NOTICE,
503 				    "\"%s\" command from %s (%s)",
504 				    c->cmdname, RealHostName,
505 				    inet_ntoa(RealHostAddr.sin_addr));
506 # endif
507 			/* FALL THROUGH */
508 # endif /* SMTPDEBUG */
509 
510 		  case CMDERROR:	/* unknown command */
511 			message("500", "Command unrecognized");
512 			break;
513 
514 		  default:
515 			errno = 0;
516 			syserr("smtp: unknown code %d", c->cmdcode);
517 			break;
518 		}
519 	}
520 }
521 /*
522 **  SKIPWORD -- skip a fixed word.
523 **
524 **	Parameters:
525 **		p -- place to start looking.
526 **		w -- word to skip.
527 **
528 **	Returns:
529 **		p following w.
530 **		NULL on error.
531 **
532 **	Side Effects:
533 **		clobbers the p data area.
534 */
535 
536 static char *
537 skipword(p, w)
538 	register char *p;
539 	char *w;
540 {
541 	register char *q;
542 
543 	/* find beginning of word */
544 	while (isascii(*p) && isspace(*p))
545 		p++;
546 	q = p;
547 
548 	/* find end of word */
549 	while (*p != '\0' && *p != ':' && !(isascii(*p) && isspace(*p)))
550 		p++;
551 	while (isascii(*p) && isspace(*p))
552 		*p++ = '\0';
553 	if (*p != ':')
554 	{
555 	  syntax:
556 		message("501", "Syntax error");
557 		Errors++;
558 		return (NULL);
559 	}
560 	*p++ = '\0';
561 	while (isascii(*p) && isspace(*p))
562 		p++;
563 
564 	/* see if the input word matches desired word */
565 	if (strcasecmp(q, w))
566 		goto syntax;
567 
568 	return (p);
569 }
570 /*
571 **  HELP -- implement the HELP command.
572 **
573 **	Parameters:
574 **		topic -- the topic we want help for.
575 **
576 **	Returns:
577 **		none.
578 **
579 **	Side Effects:
580 **		outputs the help file to message output.
581 */
582 
583 help(topic)
584 	char *topic;
585 {
586 	register FILE *hf;
587 	int len;
588 	char buf[MAXLINE];
589 	bool noinfo;
590 
591 	if (HelpFile == NULL || (hf = fopen(HelpFile, "r")) == NULL)
592 	{
593 		/* no help */
594 		errno = 0;
595 		message("502", "HELP not implemented");
596 		return;
597 	}
598 
599 	if (topic == NULL || *topic == '\0')
600 		topic = "smtp";
601 	else
602 		makelower(topic);
603 
604 	len = strlen(topic);
605 	noinfo = TRUE;
606 
607 	while (fgets(buf, sizeof buf, hf) != NULL)
608 	{
609 		if (strncmp(buf, topic, len) == 0)
610 		{
611 			register char *p;
612 
613 			p = strchr(buf, '\t');
614 			if (p == NULL)
615 				p = buf;
616 			else
617 				p++;
618 			fixcrlf(p, TRUE);
619 			message("214-", p);
620 			noinfo = FALSE;
621 		}
622 	}
623 
624 	if (noinfo)
625 		message("504", "HELP topic unknown");
626 	else
627 		message("214", "End of HELP info");
628 	(void) fclose(hf);
629 }
630 /*
631 **  RUNINCHILD -- return twice -- once in the child, then in the parent again
632 **
633 **	Parameters:
634 **		label -- a string used in error messages
635 **
636 **	Returns:
637 **		zero in the child
638 **		one in the parent
639 **
640 **	Side Effects:
641 **		none.
642 */
643 
644 runinchild(label, e)
645 	char *label;
646 	register ENVELOPE *e;
647 {
648 	int childpid;
649 
650 	if (!OneXact)
651 	{
652 		childpid = dofork();
653 		if (childpid < 0)
654 		{
655 			syserr("%s: cannot fork", label);
656 			return (1);
657 		}
658 		if (childpid > 0)
659 		{
660 			auto int st;
661 
662 			/* parent -- wait for child to complete */
663 			st = waitfor(childpid);
664 			if (st == -1)
665 				syserr("%s: lost child", label);
666 
667 			/* if we exited on a QUIT command, complete the process */
668 			if (st == (EX_QUIT << 8))
669 				finis();
670 
671 			return (1);
672 		}
673 		else
674 		{
675 			/* child */
676 			InChild = TRUE;
677 			QuickAbort = FALSE;
678 			clearenvelope(e, FALSE);
679 		}
680 	}
681 
682 	/* open alias database */
683 	initaliases(AliasFile, FALSE, e);
684 
685 	return (0);
686 }
687 
688 # endif /* SMTP */
689