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	5.39 (Berkeley) 11/14/92 (with SMTP)";
14 #else
15 static char sccsid[] = "@(#)srvrsmtp.c	5.39 (Berkeley) 11/14/92 (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 #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 = p;
172 		for (cmd = cmdbuf; *p != '\0' && !isspace(*p); )
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,
246 				CurHostName, inp);
247 
248 			/* child -- go do the processing */
249 			p = skipword(p, "from");
250 			if (p == NULL)
251 				break;
252 			setsender(p, e);
253 			if (Errors == 0)
254 			{
255 				message("250", "Sender ok");
256 				hasmail = TRUE;
257 			}
258 			else if (InChild)
259 				finis();
260 			break;
261 
262 		  case CMDRCPT:		/* rcpt -- designate recipient */
263 			SmtpPhase = "RCPT";
264 			setproctitle("%s %s: %s", e->e_id,
265 				CurHostName, inp);
266 			if (setjmp(TopFrame) > 0)
267 			{
268 				e->e_flags &= ~EF_FATALERRS;
269 				break;
270 			}
271 			QuickAbort = TRUE;
272 			LogUsrErrs = TRUE;
273 			p = skipword(p, "to");
274 			if (p == NULL)
275 				break;
276 			a = parseaddr(p, (ADDRESS *) NULL, 1, '\0', e);
277 			if (a == NULL)
278 				break;
279 			a->q_flags |= QPRIMARY;
280 			a = recipient(a, &e->e_sendqueue, e);
281 			if (Errors != 0)
282 				break;
283 
284 			/* no errors during parsing, but might be a duplicate */
285 			e->e_to = p;
286 			if (!bitset(QBADADDR, a->q_flags))
287 				message("250", "Recipient ok");
288 			else
289 			{
290 				/* punt -- should keep message in ADDRESS.... */
291 				message("550", "Addressee unknown");
292 			}
293 			e->e_to = NULL;
294 			break;
295 
296 		  case CMDDATA:		/* data -- text of mail */
297 			SmtpPhase = "DATA";
298 			if (!hasmail)
299 			{
300 				message("503", "Need MAIL command");
301 				break;
302 			}
303 			else if (e->e_nrcpts <= 0)
304 			{
305 				message("503", "Need RCPT (recipient)");
306 				break;
307 			}
308 
309 			/* collect the text of the message */
310 			SmtpPhase = "collect";
311 			setproctitle("%s %s: %s", e->e_id,
312 				CurHostName, inp);
313 			collect(TRUE, e);
314 			if (Errors != 0)
315 				break;
316 
317 			/*
318 			**  Arrange to send to everyone.
319 			**	If sending to multiple people, mail back
320 			**		errors rather than reporting directly.
321 			**	In any case, don't mail back errors for
322 			**		anything that has happened up to
323 			**		now (the other end will do this).
324 			**	Truncate our transcript -- the mail has gotten
325 			**		to us successfully, and if we have
326 			**		to mail this back, it will be easier
327 			**		on the reader.
328 			**	Then send to everyone.
329 			**	Finally give a reply code.  If an error has
330 			**		already been given, don't mail a
331 			**		message back.
332 			**	We goose error returns by clearing error bit.
333 			*/
334 
335 			SmtpPhase = "delivery";
336 			if (e->e_nrcpts != 1)
337 			{
338 				HoldErrs = TRUE;
339 				ErrorMode = EM_MAIL;
340 			}
341 			e->e_flags &= ~EF_FATALERRS;
342 			e->e_xfp = freopen(queuename(e, 'x'), "w", e->e_xfp);
343 
344 			/* send to all recipients */
345 			sendall(e, SM_DEFAULT);
346 			e->e_to = NULL;
347 
348 			/* save statistics */
349 			markstats(e, (ADDRESS *) NULL);
350 
351 			/* issue success if appropriate and reset */
352 			if (Errors == 0 || HoldErrs)
353 				message("250", "Ok");
354 			else
355 				e->e_flags &= ~EF_FATALERRS;
356 
357 			/* if in a child, pop back to our parent */
358 			if (InChild)
359 				finis();
360 
361 			/* clean up a bit */
362 			hasmail = 0;
363 			dropenvelope(e);
364 			CurEnv = e = newenvelope(e);
365 			e->e_flags = BlankEnvelope.e_flags;
366 			break;
367 
368 		  case CMDRSET:		/* rset -- reset state */
369 			message("250", "Reset state");
370 			if (InChild)
371 				finis();
372 			break;
373 
374 		  case CMDVRFY:		/* vrfy -- verify address */
375 			if (runinchild("SMTP-VRFY", e) > 0)
376 				break;
377 			setproctitle("%s: %s", CurHostName, inp);
378 #ifdef LOG
379 			if (LogLevel >= 9)
380 				syslog(LOG_INFO, "%s: %s", CurHostName, inp);
381 #endif
382 			vrfyqueue = NULL;
383 			QuickAbort = TRUE;
384 			sendtolist(p, (ADDRESS *) NULL, &vrfyqueue, e);
385 			if (Errors != 0)
386 			{
387 				if (InChild)
388 					finis();
389 				break;
390 			}
391 			while (vrfyqueue != NULL)
392 			{
393 				register ADDRESS *a = vrfyqueue->q_next;
394 				char *code;
395 
396 				while (a != NULL && bitset(QDONTSEND|QBADADDR, a->q_flags))
397 					a = a->q_next;
398 
399 				if (!bitset(QDONTSEND|QBADADDR, vrfyqueue->q_flags))
400 				{
401 					if (a != NULL)
402 						code = "250-";
403 					else
404 						code = "250";
405 					if (vrfyqueue->q_fullname == NULL)
406 						message(code, "<%s>", vrfyqueue->q_paddr);
407 					else
408 						message(code, "%s <%s>",
409 						    vrfyqueue->q_fullname, vrfyqueue->q_paddr);
410 				}
411 				else if (a == NULL)
412 					message("554", "Self destructive alias loop");
413 				vrfyqueue = a;
414 			}
415 			if (InChild)
416 				finis();
417 			break;
418 
419 		  case CMDHELP:		/* help -- give user info */
420 			help(p);
421 			break;
422 
423 		  case CMDNOOP:		/* noop -- do nothing */
424 			message("200", "OK");
425 			break;
426 
427 		  case CMDQUIT:		/* quit -- leave mail */
428 			message("221", "%s closing connection", MyHostName);
429 			if (InChild)
430 				ExitStat = EX_QUIT;
431 			finis();
432 
433 		  case CMDVERB:		/* set verbose mode */
434 			Verbose = TRUE;
435 			SendMode = SM_DELIVER;
436 			message("200", "Verbose mode");
437 			break;
438 
439 		  case CMDONEX:		/* doing one transaction only */
440 			OneXact = TRUE;
441 			message("200", "Only one transaction");
442 			break;
443 
444 # ifdef SMTPDEBUG
445 		  case CMDDBGQSHOW:	/* show queues */
446 			printf("Send Queue=");
447 			printaddr(e->e_sendqueue, TRUE);
448 			break;
449 
450 		  case CMDDBGDEBUG:	/* set debug mode */
451 			tTsetup(tTdvect, sizeof tTdvect, "0-99.1");
452 			tTflag(p);
453 			message("200", "Debug set");
454 			break;
455 
456 # else /* not SMTPDEBUG */
457 
458 		  case CMDDBGQSHOW:	/* show queues */
459 		  case CMDDBGDEBUG:	/* set debug mode */
460 # ifdef LOG
461 			if (RealHostName != NULL && LogLevel > 0)
462 				syslog(LOG_NOTICE,
463 				    "\"%s\" command from %s (%s)\n",
464 				    c->cmdname, RealHostName,
465 				    inet_ntoa(RealHostAddr.sin_addr));
466 # endif
467 			/* FALL THROUGH */
468 # endif /* SMTPDEBUG */
469 
470 		  case CMDERROR:	/* unknown command */
471 			message("500", "Command unrecognized");
472 			break;
473 
474 		  default:
475 			errno = 0;
476 			syserr("smtp: unknown code %d", c->cmdcode);
477 			break;
478 		}
479 	}
480 }
481 /*
482 **  SKIPWORD -- skip a fixed word.
483 **
484 **	Parameters:
485 **		p -- place to start looking.
486 **		w -- word to skip.
487 **
488 **	Returns:
489 **		p following w.
490 **		NULL on error.
491 **
492 **	Side Effects:
493 **		clobbers the p data area.
494 */
495 
496 static char *
497 skipword(p, w)
498 	register char *p;
499 	char *w;
500 {
501 	register char *q;
502 
503 	/* find beginning of word */
504 	while (isspace(*p))
505 		p++;
506 	q = p;
507 
508 	/* find end of word */
509 	while (*p != '\0' && *p != ':' && !isspace(*p))
510 		p++;
511 	while (isspace(*p))
512 		*p++ = '\0';
513 	if (*p != ':')
514 	{
515 	  syntax:
516 		message("501", "Syntax error");
517 		Errors++;
518 		return (NULL);
519 	}
520 	*p++ = '\0';
521 	while (isspace(*p))
522 		p++;
523 
524 	/* see if the input word matches desired word */
525 	if (strcasecmp(q, w))
526 		goto syntax;
527 
528 	return (p);
529 }
530 /*
531 **  HELP -- implement the HELP command.
532 **
533 **	Parameters:
534 **		topic -- the topic we want help for.
535 **
536 **	Returns:
537 **		none.
538 **
539 **	Side Effects:
540 **		outputs the help file to message output.
541 */
542 
543 help(topic)
544 	char *topic;
545 {
546 	register FILE *hf;
547 	int len;
548 	char buf[MAXLINE];
549 	bool noinfo;
550 
551 	if (HelpFile == NULL || (hf = fopen(HelpFile, "r")) == NULL)
552 	{
553 		/* no help */
554 		errno = 0;
555 		message("502", "HELP not implemented");
556 		return;
557 	}
558 
559 	if (topic == NULL || *topic == '\0')
560 		topic = "smtp";
561 	else
562 		makelower(topic);
563 
564 	len = strlen(topic);
565 	noinfo = TRUE;
566 
567 	while (fgets(buf, sizeof buf, hf) != NULL)
568 	{
569 		if (strncmp(buf, topic, len) == 0)
570 		{
571 			register char *p;
572 
573 			p = strchr(buf, '\t');
574 			if (p == NULL)
575 				p = buf;
576 			else
577 				p++;
578 			fixcrlf(p, TRUE);
579 			message("214-", p);
580 			noinfo = FALSE;
581 		}
582 	}
583 
584 	if (noinfo)
585 		message("504", "HELP topic unknown");
586 	else
587 		message("214", "End of HELP info");
588 	(void) fclose(hf);
589 }
590 /*
591 **  RUNINCHILD -- return twice -- once in the child, then in the parent again
592 **
593 **	Parameters:
594 **		label -- a string used in error messages
595 **
596 **	Returns:
597 **		zero in the child
598 **		one in the parent
599 **
600 **	Side Effects:
601 **		none.
602 */
603 
604 runinchild(label, e)
605 	char *label;
606 	register ENVELOPE *e;
607 {
608 	int childpid;
609 
610 	if (!OneXact)
611 	{
612 		childpid = dofork();
613 		if (childpid < 0)
614 		{
615 			syserr("%s: cannot fork", label);
616 			return (1);
617 		}
618 		if (childpid > 0)
619 		{
620 			auto int st;
621 
622 			/* parent -- wait for child to complete */
623 			st = waitfor(childpid);
624 			if (st == -1)
625 				syserr("%s: lost child", label);
626 
627 			/* if we exited on a QUIT command, complete the process */
628 			if (st == (EX_QUIT << 8))
629 				finis();
630 
631 			return (1);
632 		}
633 		else
634 		{
635 			/* child */
636 			InChild = TRUE;
637 			QuickAbort = FALSE;
638 			clearenvelope(e, FALSE);
639 		}
640 	}
641 
642 	/* open alias database */
643 	initaliases(AliasFile, FALSE, e);
644 
645 	return (0);
646 }
647 
648 # endif /* SMTP */
649