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	6.2 (Berkeley) 01/01/93 (with SMTP)";
14 #else
15 static char sccsid[] = "@(#)srvrsmtp.c	6.2 (Berkeley) 01/01/93 (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 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[MAXLINE];
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, 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 >= 4)
155 				syslog(LOG_NOTICE, "lost input channel from %s",
156 					CurHostName);
157 #endif
158 			finis();
159 		}
160 
161 		/* clean up end of line */
162 		fixcrlf(inp, TRUE);
163 
164 		/* echo command to transcript */
165 		if (e->e_xfp != NULL)
166 			fprintf(e->e_xfp, "<<< %s\n", inp);
167 
168 		/* break off command */
169 		for (p = inp; isspace(*p); p++)
170 			continue;
171 		cmd = cmdbuf;
172 		while (*p != '\0' && !isspace(*p) && cmd < &cmdbuf[sizeof cmdbuf - 2])
173 			*cmd++ = *p++;
174 		*cmd = '\0';
175 
176 		/* throw away leading whitespace */
177 		while (isspace(*p))
178 			p++;
179 
180 		/* decode command */
181 		for (c = CmdTab; c->cmdname != NULL; c++)
182 		{
183 			if (!strcasecmp(c->cmdname, cmdbuf))
184 				break;
185 		}
186 
187 		/* reset errors */
188 		errno = 0;
189 
190 		/* process command */
191 		switch (c->cmdcode)
192 		{
193 		  case CMDHELO:		/* hello -- introduce yourself */
194 			SmtpPhase = "HELO";
195 			setproctitle("%s: %s", CurHostName, inp);
196 			if (!strcasecmp(p, MyHostName))
197 			{
198 				/*
199 				 * didn't know about alias,
200 				 * or connected to an echo server
201 				 */
202 				message("553", "%s config error: mail loops back to myself",
203 					MyHostName);
204 				break;
205 			}
206 			if (RealHostName != NULL && strcasecmp(p, RealHostName))
207 			{
208 				char hostbuf[MAXNAME];
209 
210 				(void) sprintf(hostbuf, "%s (%s)", p, RealHostName);
211 				sendinghost = newstr(hostbuf);
212 			}
213 			else
214 				sendinghost = newstr(p);
215 			message("250", "%s Hello %s, pleased to meet you",
216 				MyHostName, sendinghost);
217 			break;
218 
219 		  case CMDMAIL:		/* mail -- designate sender */
220 			SmtpPhase = "MAIL";
221 
222 			/* force a sending host even if no HELO given */
223 			if (RealHostName != NULL && macvalue('s', e) == NULL)
224 				sendinghost = RealHostName;
225 
226 			/* check for validity of this command */
227 			if (hasmail)
228 			{
229 				message("503", "Sender already specified");
230 				break;
231 			}
232 			if (InChild)
233 			{
234 				errno = 0;
235 				syserr("Nested MAIL command");
236 				exit(0);
237 			}
238 
239 			/* fork a subprocess to process this command */
240 			if (runinchild("SMTP-MAIL", e) > 0)
241 				break;
242 			define('s', sendinghost, e);
243 			define('r', "SMTP", e);
244 			initsys(e);
245 			setproctitle("%s %s: %s", e->e_id, CurHostName, inp);
246 
247 			/* child -- go do the processing */
248 			p = skipword(p, "from");
249 			if (p == NULL)
250 				break;
251 			setsender(p, e);
252 			if (Errors == 0)
253 			{
254 				message("250", "Sender ok");
255 				hasmail = TRUE;
256 			}
257 			else if (InChild)
258 				finis();
259 			break;
260 
261 		  case CMDRCPT:		/* rcpt -- designate recipient */
262 			SmtpPhase = "RCPT";
263 			setproctitle("%s %s: %s", e->e_id, CurHostName, inp);
264 			if (setjmp(TopFrame) > 0)
265 			{
266 				e->e_flags &= ~EF_FATALERRS;
267 				break;
268 			}
269 			QuickAbort = TRUE;
270 			LogUsrErrs = TRUE;
271 			p = skipword(p, "to");
272 			if (p == NULL)
273 				break;
274 			a = parseaddr(p, (ADDRESS *) NULL, 1, '\0', e);
275 			if (a == NULL)
276 				break;
277 			a->q_flags |= QPRIMARY;
278 			a = recipient(a, &e->e_sendqueue, e);
279 			if (Errors != 0)
280 				break;
281 
282 			/* no errors during parsing, but might be a duplicate */
283 			e->e_to = p;
284 			if (!bitset(QBADADDR, a->q_flags))
285 				message("250", "Recipient ok");
286 			else
287 			{
288 				/* punt -- should keep message in ADDRESS.... */
289 				message("550", "Addressee unknown");
290 			}
291 			e->e_to = NULL;
292 			break;
293 
294 		  case CMDDATA:		/* data -- text of mail */
295 			SmtpPhase = "DATA";
296 			if (!hasmail)
297 			{
298 				message("503", "Need MAIL command");
299 				break;
300 			}
301 			else if (e->e_nrcpts <= 0)
302 			{
303 				message("503", "Need RCPT (recipient)");
304 				break;
305 			}
306 
307 			/* collect the text of the message */
308 			SmtpPhase = "collect";
309 			setproctitle("%s %s: %s", e->e_id, CurHostName, inp);
310 			collect(TRUE, e);
311 			if (Errors != 0)
312 				break;
313 
314 			/*
315 			**  Arrange to send to everyone.
316 			**	If sending to multiple people, mail back
317 			**		errors rather than reporting directly.
318 			**	In any case, don't mail back errors for
319 			**		anything that has happened up to
320 			**		now (the other end will do this).
321 			**	Truncate our transcript -- the mail has gotten
322 			**		to us successfully, and if we have
323 			**		to mail this back, it will be easier
324 			**		on the reader.
325 			**	Then send to everyone.
326 			**	Finally give a reply code.  If an error has
327 			**		already been given, don't mail a
328 			**		message back.
329 			**	We goose error returns by clearing error bit.
330 			*/
331 
332 			SmtpPhase = "delivery";
333 			if (e->e_nrcpts != 1)
334 			{
335 				HoldErrs = TRUE;
336 				ErrorMode = EM_MAIL;
337 			}
338 			e->e_flags &= ~EF_FATALERRS;
339 			e->e_xfp = freopen(queuename(e, 'x'), "w", e->e_xfp);
340 
341 			/* send to all recipients */
342 			sendall(e, SM_DEFAULT);
343 			e->e_to = NULL;
344 
345 			/* save statistics */
346 			markstats(e, (ADDRESS *) NULL);
347 
348 			/* issue success if appropriate and reset */
349 			if (Errors == 0 || HoldErrs)
350 				message("250", "Ok");
351 			else
352 				e->e_flags &= ~EF_FATALERRS;
353 
354 			/* if in a child, pop back to our parent */
355 			if (InChild)
356 				finis();
357 
358 			/* clean up a bit */
359 			hasmail = 0;
360 			dropenvelope(e);
361 			CurEnv = e = newenvelope(e);
362 			e->e_flags = BlankEnvelope.e_flags;
363 			break;
364 
365 		  case CMDRSET:		/* rset -- reset state */
366 			message("250", "Reset state");
367 			if (InChild)
368 				finis();
369 			break;
370 
371 		  case CMDVRFY:		/* vrfy -- verify address */
372 			if (runinchild("SMTP-VRFY", e) > 0)
373 				break;
374 			setproctitle("%s: %s", CurHostName, inp);
375 #ifdef LOG
376 			if (LogLevel >= 9)
377 				syslog(LOG_INFO, "%s: %s", CurHostName, inp);
378 #endif
379 			vrfyqueue = NULL;
380 			QuickAbort = TRUE;
381 			sendtolist(p, (ADDRESS *) NULL, &vrfyqueue, e);
382 			if (Errors != 0)
383 			{
384 				if (InChild)
385 					finis();
386 				break;
387 			}
388 			while (vrfyqueue != NULL)
389 			{
390 				register ADDRESS *a = vrfyqueue->q_next;
391 				char *code;
392 
393 				while (a != NULL && bitset(QDONTSEND|QBADADDR, a->q_flags))
394 					a = a->q_next;
395 
396 				if (!bitset(QDONTSEND|QBADADDR, vrfyqueue->q_flags))
397 				{
398 					if (a != NULL)
399 						code = "250-";
400 					else
401 						code = "250";
402 					if (vrfyqueue->q_fullname == NULL)
403 						message(code, "<%s>", vrfyqueue->q_paddr);
404 					else
405 						message(code, "%s <%s>",
406 						    vrfyqueue->q_fullname, vrfyqueue->q_paddr);
407 				}
408 				else if (a == NULL)
409 					message("554", "Self destructive alias loop");
410 				vrfyqueue = a;
411 			}
412 			if (InChild)
413 				finis();
414 			break;
415 
416 		  case CMDHELP:		/* help -- give user info */
417 			help(p);
418 			break;
419 
420 		  case CMDNOOP:		/* noop -- do nothing */
421 			message("200", "OK");
422 			break;
423 
424 		  case CMDQUIT:		/* quit -- leave mail */
425 			message("221", "%s closing connection", MyHostName);
426 			if (InChild)
427 				ExitStat = EX_QUIT;
428 			finis();
429 
430 		  case CMDVERB:		/* set verbose mode */
431 			Verbose = TRUE;
432 			SendMode = SM_DELIVER;
433 			message("200", "Verbose mode");
434 			break;
435 
436 		  case CMDONEX:		/* doing one transaction only */
437 			OneXact = TRUE;
438 			message("200", "Only one transaction");
439 			break;
440 
441 # ifdef SMTPDEBUG
442 		  case CMDDBGQSHOW:	/* show queues */
443 			printf("Send Queue=");
444 			printaddr(e->e_sendqueue, TRUE);
445 			break;
446 
447 		  case CMDDBGDEBUG:	/* set debug mode */
448 			tTsetup(tTdvect, sizeof tTdvect, "0-99.1");
449 			tTflag(p);
450 			message("200", "Debug set");
451 			break;
452 
453 # else /* not SMTPDEBUG */
454 
455 		  case CMDDBGQSHOW:	/* show queues */
456 		  case CMDDBGDEBUG:	/* set debug mode */
457 # ifdef LOG
458 			if (RealHostName != NULL && LogLevel > 0)
459 				syslog(LOG_NOTICE,
460 				    "\"%s\" command from %s (%s)\n",
461 				    c->cmdname, RealHostName,
462 				    inet_ntoa(RealHostAddr.sin_addr));
463 # endif
464 			/* FALL THROUGH */
465 # endif /* SMTPDEBUG */
466 
467 		  case CMDERROR:	/* unknown command */
468 			message("500", "Command unrecognized");
469 			break;
470 
471 		  default:
472 			errno = 0;
473 			syserr("smtp: unknown code %d", c->cmdcode);
474 			break;
475 		}
476 	}
477 }
478 /*
479 **  SKIPWORD -- skip a fixed word.
480 **
481 **	Parameters:
482 **		p -- place to start looking.
483 **		w -- word to skip.
484 **
485 **	Returns:
486 **		p following w.
487 **		NULL on error.
488 **
489 **	Side Effects:
490 **		clobbers the p data area.
491 */
492 
493 static char *
494 skipword(p, w)
495 	register char *p;
496 	char *w;
497 {
498 	register char *q;
499 
500 	/* find beginning of word */
501 	while (isspace(*p))
502 		p++;
503 	q = p;
504 
505 	/* find end of word */
506 	while (*p != '\0' && *p != ':' && !isspace(*p))
507 		p++;
508 	while (isspace(*p))
509 		*p++ = '\0';
510 	if (*p != ':')
511 	{
512 	  syntax:
513 		message("501", "Syntax error");
514 		Errors++;
515 		return (NULL);
516 	}
517 	*p++ = '\0';
518 	while (isspace(*p))
519 		p++;
520 
521 	/* see if the input word matches desired word */
522 	if (strcasecmp(q, w))
523 		goto syntax;
524 
525 	return (p);
526 }
527 /*
528 **  HELP -- implement the HELP command.
529 **
530 **	Parameters:
531 **		topic -- the topic we want help for.
532 **
533 **	Returns:
534 **		none.
535 **
536 **	Side Effects:
537 **		outputs the help file to message output.
538 */
539 
540 help(topic)
541 	char *topic;
542 {
543 	register FILE *hf;
544 	int len;
545 	char buf[MAXLINE];
546 	bool noinfo;
547 
548 	if (HelpFile == NULL || (hf = fopen(HelpFile, "r")) == NULL)
549 	{
550 		/* no help */
551 		errno = 0;
552 		message("502", "HELP not implemented");
553 		return;
554 	}
555 
556 	if (topic == NULL || *topic == '\0')
557 		topic = "smtp";
558 	else
559 		makelower(topic);
560 
561 	len = strlen(topic);
562 	noinfo = TRUE;
563 
564 	while (fgets(buf, sizeof buf, hf) != NULL)
565 	{
566 		if (strncmp(buf, topic, len) == 0)
567 		{
568 			register char *p;
569 
570 			p = strchr(buf, '\t');
571 			if (p == NULL)
572 				p = buf;
573 			else
574 				p++;
575 			fixcrlf(p, TRUE);
576 			message("214-", p);
577 			noinfo = FALSE;
578 		}
579 	}
580 
581 	if (noinfo)
582 		message("504", "HELP topic unknown");
583 	else
584 		message("214", "End of HELP info");
585 	(void) fclose(hf);
586 }
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, e)
602 	char *label;
603 	register ENVELOPE *e;
604 {
605 	int childpid;
606 
607 	if (!OneXact)
608 	{
609 		childpid = dofork();
610 		if (childpid < 0)
611 		{
612 			syserr("%s: cannot fork", label);
613 			return (1);
614 		}
615 		if (childpid > 0)
616 		{
617 			auto int st;
618 
619 			/* parent -- wait for child to complete */
620 			st = waitfor(childpid);
621 			if (st == -1)
622 				syserr("%s: lost child", label);
623 
624 			/* if we exited on a QUIT command, complete the process */
625 			if (st == (EX_QUIT << 8))
626 				finis();
627 
628 			return (1);
629 		}
630 		else
631 		{
632 			/* child */
633 			InChild = TRUE;
634 			QuickAbort = FALSE;
635 			clearenvelope(e, FALSE);
636 		}
637 	}
638 
639 	/* open alias database */
640 	initaliases(AliasFile, FALSE, e);
641 
642 	return (0);
643 }
644 
645 # endif /* SMTP */
646