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	5.37 (Berkeley) 07/19/92 (with SMTP)";
14 #else
15 static char sccsid[] = "@(#)srvrsmtp.c	5.37 (Berkeley) 07/19/92 (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 CMDHELP	6	/* help -- give usage info */
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 CMDONEX	10	/* onex -- sending one transaction only */
56 # define CMDVERB	11	/* verb -- go into verbose mode */
57 /* debugging-only commands, only enabled if SMTPDEBUG is defined */
58 # define CMDDBGQSHOW	12	/* showq -- show send queue */
59 # define CMDDBGDEBUG	13	/* debug -- set debug mode */
60 
61 static struct cmd	CmdTab[] =
62 {
63 	"mail",		CMDMAIL,
64 	"rcpt",		CMDRCPT,
65 	"data",		CMDDATA,
66 	"rset",		CMDRSET,
67 	"vrfy",		CMDVRFY,
68 	"expn",		CMDVRFY,
69 	"help",		CMDHELP,
70 	"noop",		CMDNOOP,
71 	"quit",		CMDQUIT,
72 	"helo",		CMDHELO,
73 	"verb",		CMDVERB,
74 	"onex",		CMDONEX,
75 	/*
76 	 * remaining commands are here only
77 	 * to trap and log attempts to use them
78 	 */
79 	"showq",	CMDDBGQSHOW,
80 	"debug",	CMDDBGDEBUG,
81 	NULL,		CMDERROR,
82 };
83 
84 bool	InChild = FALSE;		/* true if running in a subprocess */
85 bool	OneXact = FALSE;		/* one xaction only this run */
86 
87 #define EX_QUIT		22		/* special code for QUIT command */
88 
89 smtp(e)
90 	register ENVELOPE *e;
91 {
92 	register char *p;
93 	register struct cmd *c;
94 	char *cmd;
95 	static char *skipword();
96 	bool hasmail;			/* mail command received */
97 	auto ADDRESS *vrfyqueue;
98 	ADDRESS *a;
99 	char *sendinghost;
100 	char inp[MAXLINE];
101 	char cmdbuf[100];
102 	extern char Version[];
103 	extern char *macvalue();
104 	extern ADDRESS *recipient();
105 	extern ENVELOPE BlankEnvelope;
106 	extern ENVELOPE *newenvelope();
107 
108 	hasmail = FALSE;
109 	if (OutChannel != stdout)
110 	{
111 		/* arrange for debugging output to go to remote host */
112 		(void) close(1);
113 		(void) dup(fileno(OutChannel));
114 	}
115 	settime(e);
116 	if (RealHostName != NULL)
117 	{
118 		CurHostName = RealHostName;
119 		setproctitle("srvrsmtp %s", CurHostName);
120 	}
121 	else
122 	{
123 		/* this must be us!! */
124 		CurHostName = MyHostName;
125 	}
126 	expand("\001e", inp, &inp[sizeof inp], e);
127 	message("220", "%s", inp);
128 	SmtpPhase = "startup";
129 	sendinghost = NULL;
130 	for (;;)
131 	{
132 		/* arrange for backout */
133 		if (setjmp(TopFrame) > 0 && InChild)
134 			finis();
135 		QuickAbort = FALSE;
136 		HoldErrs = FALSE;
137 		LogUsrErrs = FALSE;
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);
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 			finis();
154 		}
155 
156 		/* clean up end of line */
157 		fixcrlf(inp, TRUE);
158 
159 		/* echo command to transcript */
160 		if (e->e_xfp != NULL)
161 			fprintf(e->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 		/* throw away leading whitespace */
172 		while (isspace(*p))
173 			p++;
174 
175 		/* decode command */
176 		for (c = CmdTab; c->cmdname != NULL; c++)
177 		{
178 			if (!strcasecmp(c->cmdname, cmdbuf))
179 				break;
180 		}
181 
182 		/* reset errors */
183 		errno = 0;
184 
185 		/* process command */
186 		switch (c->cmdcode)
187 		{
188 		  case CMDHELO:		/* hello -- introduce yourself */
189 			SmtpPhase = "HELO";
190 			setproctitle("%s: %s", CurHostName, inp);
191 			if (!strcasecmp(p, MyHostName))
192 			{
193 				/*
194 				 * didn't know about alias,
195 				 * or connected to an echo server
196 				 */
197 				message("553", "%s config error: mail loops back to myself",
198 					MyHostName);
199 				break;
200 			}
201 			if (RealHostName != NULL && strcasecmp(p, RealHostName))
202 			{
203 				char hostbuf[MAXNAME];
204 
205 				(void) sprintf(hostbuf, "%s (%s)", p, RealHostName);
206 				sendinghost = newstr(hostbuf);
207 			}
208 			else
209 				sendinghost = newstr(p);
210 			message("250", "%s Hello %s, pleased to meet you",
211 				MyHostName, sendinghost);
212 			break;
213 
214 		  case CMDMAIL:		/* mail -- designate sender */
215 			SmtpPhase = "MAIL";
216 
217 			/* force a sending host even if no HELO given */
218 			if (RealHostName != NULL && macvalue('s', e) == NULL)
219 				sendinghost = RealHostName;
220 
221 			/* check for validity of this command */
222 			if (hasmail)
223 			{
224 				message("503", "Sender already specified");
225 				break;
226 			}
227 			if (InChild)
228 			{
229 				errno = 0;
230 				syserr("Nested MAIL command");
231 				exit(0);
232 			}
233 
234 			/* fork a subprocess to process this command */
235 			if (runinchild("SMTP-MAIL", e) > 0)
236 				break;
237 			define('s', sendinghost, e);
238 			define('r', "SMTP", e);
239 			initsys(e);
240 			setproctitle("%s %s: %s", e->e_id,
241 				CurHostName, inp);
242 
243 			/* child -- go do the processing */
244 			p = skipword(p, "from");
245 			if (p == NULL)
246 				break;
247 			setsender(p, e);
248 			if (Errors == 0)
249 			{
250 				message("250", "Sender ok");
251 				hasmail = TRUE;
252 			}
253 			else if (InChild)
254 				finis();
255 			break;
256 
257 		  case CMDRCPT:		/* rcpt -- designate recipient */
258 			SmtpPhase = "RCPT";
259 			setproctitle("%s %s: %s", e->e_id,
260 				CurHostName, inp);
261 			if (setjmp(TopFrame) > 0)
262 			{
263 				e->e_flags &= ~EF_FATALERRS;
264 				break;
265 			}
266 			QuickAbort = TRUE;
267 			LogUsrErrs = TRUE;
268 			p = skipword(p, "to");
269 			if (p == NULL)
270 				break;
271 			a = parseaddr(p, (ADDRESS *) NULL, 1, '\0', e);
272 			if (a == NULL)
273 				break;
274 			a->q_flags |= QPRIMARY;
275 			a = recipient(a, &e->e_sendqueue, e);
276 			if (Errors != 0)
277 				break;
278 
279 			/* no errors during parsing, but might be a duplicate */
280 			e->e_to = p;
281 			if (!bitset(QBADADDR, a->q_flags))
282 				message("250", "Recipient ok");
283 			else
284 			{
285 				/* punt -- should keep message in ADDRESS.... */
286 				message("550", "Addressee unknown");
287 			}
288 			e->e_to = NULL;
289 			break;
290 
291 		  case CMDDATA:		/* data -- text of mail */
292 			SmtpPhase = "DATA";
293 			if (!hasmail)
294 			{
295 				message("503", "Need MAIL command");
296 				break;
297 			}
298 			else if (e->e_nrcpts <= 0)
299 			{
300 				message("503", "Need RCPT (recipient)");
301 				break;
302 			}
303 
304 			/* collect the text of the message */
305 			SmtpPhase = "collect";
306 			setproctitle("%s %s: %s", e->e_id,
307 				CurHostName, inp);
308 			collect(TRUE, e);
309 			if (Errors != 0)
310 				break;
311 
312 			/*
313 			**  Arrange to send to everyone.
314 			**	If sending to multiple people, mail back
315 			**		errors rather than reporting directly.
316 			**	In any case, don't mail back errors for
317 			**		anything that has happened up to
318 			**		now (the other end will do this).
319 			**	Truncate our transcript -- the mail has gotten
320 			**		to us successfully, and if we have
321 			**		to mail this back, it will be easier
322 			**		on the reader.
323 			**	Then send to everyone.
324 			**	Finally give a reply code.  If an error has
325 			**		already been given, don't mail a
326 			**		message back.
327 			**	We goose error returns by clearing error bit.
328 			*/
329 
330 			SmtpPhase = "delivery";
331 			if (e->e_nrcpts != 1)
332 			{
333 				HoldErrs = TRUE;
334 				ErrorMode = EM_MAIL;
335 			}
336 			e->e_flags &= ~EF_FATALERRS;
337 			e->e_xfp = freopen(queuename(e, 'x'), "w", e->e_xfp);
338 
339 			/* send to all recipients */
340 			sendall(e, SM_DEFAULT);
341 			e->e_to = NULL;
342 
343 			/* save statistics */
344 			markstats(e, (ADDRESS *) NULL);
345 
346 			/* issue success if appropriate and reset */
347 			if (Errors == 0 || HoldErrs)
348 				message("250", "Ok");
349 			else
350 				e->e_flags &= ~EF_FATALERRS;
351 
352 			/* if in a child, pop back to our parent */
353 			if (InChild)
354 				finis();
355 
356 			/* clean up a bit */
357 			hasmail = 0;
358 			dropenvelope(e);
359 			CurEnv = e = newenvelope(e);
360 			e->e_flags = BlankEnvelope.e_flags;
361 			break;
362 
363 		  case CMDRSET:		/* rset -- reset state */
364 			message("250", "Reset state");
365 			if (InChild)
366 				finis();
367 			break;
368 
369 		  case CMDVRFY:		/* vrfy -- verify address */
370 			if (runinchild("SMTP-VRFY", e) > 0)
371 				break;
372 			setproctitle("%s: %s", CurHostName, inp);
373 #ifdef LOG
374 			if (LogLevel >= 9)
375 				syslog(LOG_INFO, "%s: %s", CurHostName, inp);
376 #endif
377 			vrfyqueue = NULL;
378 			QuickAbort = TRUE;
379 			sendtolist(p, (ADDRESS *) NULL, &vrfyqueue, e);
380 			if (Errors != 0)
381 			{
382 				if (InChild)
383 					finis();
384 				break;
385 			}
386 			while (vrfyqueue != NULL)
387 			{
388 				register ADDRESS *a = vrfyqueue->q_next;
389 				char *code;
390 
391 				while (a != NULL && bitset(QDONTSEND|QBADADDR, a->q_flags))
392 					a = a->q_next;
393 
394 				if (!bitset(QDONTSEND|QBADADDR, vrfyqueue->q_flags))
395 				{
396 					if (a != NULL)
397 						code = "250-";
398 					else
399 						code = "250";
400 					if (vrfyqueue->q_fullname == NULL)
401 						message(code, "<%s>", vrfyqueue->q_paddr);
402 					else
403 						message(code, "%s <%s>",
404 						    vrfyqueue->q_fullname, vrfyqueue->q_paddr);
405 				}
406 				else if (a == NULL)
407 					message("554", "Self destructive alias loop");
408 				vrfyqueue = a;
409 			}
410 			if (InChild)
411 				finis();
412 			break;
413 
414 		  case CMDHELP:		/* help -- give user info */
415 			help(p);
416 			break;
417 
418 		  case CMDNOOP:		/* noop -- do nothing */
419 			message("200", "OK");
420 			break;
421 
422 		  case CMDQUIT:		/* quit -- leave mail */
423 			message("221", "%s closing connection", MyHostName);
424 			if (InChild)
425 				ExitStat = EX_QUIT;
426 			finis();
427 
428 		  case CMDVERB:		/* set verbose mode */
429 			Verbose = TRUE;
430 			SendMode = SM_DELIVER;
431 			message("200", "Verbose mode");
432 			break;
433 
434 		  case CMDONEX:		/* doing one transaction only */
435 			OneXact = TRUE;
436 			message("200", "Only one transaction");
437 			break;
438 
439 # ifdef SMTPDEBUG
440 		  case CMDDBGQSHOW:	/* show queues */
441 			printf("Send Queue=");
442 			printaddr(e->e_sendqueue, TRUE);
443 			break;
444 
445 		  case CMDDBGDEBUG:	/* set debug mode */
446 			tTsetup(tTdvect, sizeof tTdvect, "0-99.1");
447 			tTflag(p);
448 			message("200", "Debug set");
449 			break;
450 
451 # else /* not SMTPDEBUG */
452 
453 		  case CMDDBGQSHOW:	/* show queues */
454 		  case CMDDBGDEBUG:	/* set debug mode */
455 # ifdef LOG
456 			if (RealHostName != NULL && LogLevel > 0)
457 				syslog(LOG_NOTICE,
458 				    "\"%s\" command from %s (%s)\n",
459 				    c->cmdname, RealHostName,
460 				    inet_ntoa(RealHostAddr.sin_addr));
461 # endif
462 			/* FALL THROUGH */
463 # endif /* SMTPDEBUG */
464 
465 		  case CMDERROR:	/* unknown command */
466 			message("500", "Command unrecognized");
467 			break;
468 
469 		  default:
470 			errno = 0;
471 			syserr("smtp: unknown code %d", c->cmdcode);
472 			break;
473 		}
474 	}
475 }
476 /*
477 **  SKIPWORD -- skip a fixed word.
478 **
479 **	Parameters:
480 **		p -- place to start looking.
481 **		w -- word to skip.
482 **
483 **	Returns:
484 **		p following w.
485 **		NULL on error.
486 **
487 **	Side Effects:
488 **		clobbers the p data area.
489 */
490 
491 static char *
492 skipword(p, w)
493 	register char *p;
494 	char *w;
495 {
496 	register char *q;
497 
498 	/* find beginning of word */
499 	while (isspace(*p))
500 		p++;
501 	q = p;
502 
503 	/* find end of word */
504 	while (*p != '\0' && *p != ':' && !isspace(*p))
505 		p++;
506 	while (isspace(*p))
507 		*p++ = '\0';
508 	if (*p != ':')
509 	{
510 	  syntax:
511 		message("501", "Syntax error");
512 		Errors++;
513 		return (NULL);
514 	}
515 	*p++ = '\0';
516 	while (isspace(*p))
517 		p++;
518 
519 	/* see if the input word matches desired word */
520 	if (strcasecmp(q, w))
521 		goto syntax;
522 
523 	return (p);
524 }
525 /*
526 **  HELP -- implement the HELP command.
527 **
528 **	Parameters:
529 **		topic -- the topic we want help for.
530 **
531 **	Returns:
532 **		none.
533 **
534 **	Side Effects:
535 **		outputs the help file to message output.
536 */
537 
538 help(topic)
539 	char *topic;
540 {
541 	register FILE *hf;
542 	int len;
543 	char buf[MAXLINE];
544 	bool noinfo;
545 
546 	if (HelpFile == NULL || (hf = fopen(HelpFile, "r")) == NULL)
547 	{
548 		/* no help */
549 		errno = 0;
550 		message("502", "HELP not implemented");
551 		return;
552 	}
553 
554 	if (topic == NULL || *topic == '\0')
555 		topic = "smtp";
556 	else
557 		makelower(topic);
558 
559 	len = strlen(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 **  RUNINCHILD -- return twice -- once in the child, then in the parent again
587 **
588 **	Parameters:
589 **		label -- a string used in error messages
590 **
591 **	Returns:
592 **		zero in the child
593 **		one in the parent
594 **
595 **	Side Effects:
596 **		none.
597 */
598 
599 runinchild(label, e)
600 	char *label;
601 	register ENVELOPE *e;
602 {
603 	int childpid;
604 
605 	if (!OneXact)
606 	{
607 		childpid = dofork();
608 		if (childpid < 0)
609 		{
610 			syserr("%s: cannot fork", label);
611 			return (1);
612 		}
613 		if (childpid > 0)
614 		{
615 			auto int st;
616 
617 			/* parent -- wait for child to complete */
618 			st = waitfor(childpid);
619 			if (st == -1)
620 				syserr("%s: lost child", label);
621 
622 			/* if we exited on a QUIT command, complete the process */
623 			if (st == (EX_QUIT << 8))
624 				finis();
625 
626 			return (1);
627 		}
628 		else
629 		{
630 			/* child */
631 			InChild = TRUE;
632 			QuickAbort = FALSE;
633 			clearenvelope(e, FALSE);
634 		}
635 	}
636 
637 	/* open alias database */
638 	initaliases(AliasFile, FALSE, e);
639 
640 	return (0);
641 }
642 
643 # endif SMTP
644