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	5.32 (Berkeley) 12/15/91 (with SMTP)";
14 #else
15 static char sccsid[] = "@(#)srvrsmtp.c	5.32 (Berkeley) 12/15/91 (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()
90 {
91 	register char *p;
92 	register struct cmd *c;
93 	char *cmd;
94 	static char *skipword();
95 	bool hasmail;			/* mail command received */
96 	auto ADDRESS *vrfyqueue;
97 	ADDRESS *a;
98 	char *sendinghost;
99 	char inp[MAXLINE];
100 	char cmdbuf[100];
101 	extern char Version[];
102 	extern char *macvalue();
103 	extern ADDRESS *recipient();
104 	extern ENVELOPE BlankEnvelope;
105 	extern ENVELOPE *newenvelope();
106 
107 	hasmail = FALSE;
108 	if (OutChannel != stdout)
109 	{
110 		/* arrange for debugging output to go to remote host */
111 		(void) close(1);
112 		(void) dup(fileno(OutChannel));
113 	}
114 	settime();
115 	if (RealHostName != NULL)
116 	{
117 		CurHostName = RealHostName;
118 		setproctitle("srvrsmtp %s", CurHostName);
119 	}
120 	else
121 	{
122 		/* this must be us!! */
123 		CurHostName = MyHostName;
124 	}
125 	expand("\001e", inp, &inp[sizeof inp], CurEnv);
126 	message("220", inp);
127 	SmtpPhase = "startup";
128 	sendinghost = NULL;
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 
138 		/* setup for the read */
139 		CurEnv->e_to = NULL;
140 		Errors = 0;
141 		(void) fflush(stdout);
142 
143 		/* read the input line */
144 		p = sfgets(inp, sizeof inp, InChannel);
145 
146 		/* handle errors */
147 		if (p == NULL)
148 		{
149 			/* end of file, just die */
150 			message("421", "%s Lost input channel from %s",
151 				MyHostName, CurHostName);
152 			finis();
153 		}
154 
155 		/* clean up end of line */
156 		fixcrlf(inp, TRUE);
157 
158 		/* echo command to transcript */
159 		if (CurEnv->e_xfp != NULL)
160 			fprintf(CurEnv->e_xfp, "<<< %s\n", inp);
161 
162 		/* break off command */
163 		for (p = inp; isspace(*p); p++)
164 			continue;
165 		cmd = p;
166 		for (cmd = cmdbuf; *p != '\0' && !isspace(*p); )
167 			*cmd++ = *p++;
168 		*cmd = '\0';
169 
170 		/* throw away leading whitespace */
171 		while (isspace(*p))
172 			p++;
173 
174 		/* decode command */
175 		for (c = CmdTab; c->cmdname != NULL; c++)
176 		{
177 			if (!strcasecmp(c->cmdname, cmdbuf))
178 				break;
179 		}
180 
181 		/* process command */
182 		switch (c->cmdcode)
183 		{
184 		  case CMDHELO:		/* hello -- introduce yourself */
185 			SmtpPhase = "HELO";
186 			setproctitle("%s: %s", CurHostName, inp);
187 			if (!strcasecmp(p, MyHostName))
188 			{
189 				/*
190 				 * didn't know about alias,
191 				 * or connected to an echo server
192 				 */
193 				message("553", "%s config error: mail loops back to myself",
194 					MyHostName);
195 				break;
196 			}
197 			if (RealHostName != NULL && strcasecmp(p, RealHostName))
198 			{
199 				char hostbuf[MAXNAME];
200 
201 				(void) sprintf(hostbuf, "%s (%s)", p, RealHostName);
202 				sendinghost = newstr(hostbuf);
203 			}
204 			else
205 				sendinghost = newstr(p);
206 			message("250", "%s Hello %s, pleased to meet you",
207 				MyHostName, sendinghost);
208 			break;
209 
210 		  case CMDMAIL:		/* mail -- designate sender */
211 			SmtpPhase = "MAIL";
212 
213 			/* force a sending host even if no HELO given */
214 			if (RealHostName != NULL && macvalue('s', CurEnv) == NULL)
215 				sendinghost = RealHostName;
216 
217 			/* check for validity of this command */
218 			if (hasmail)
219 			{
220 				message("503", "Sender already specified");
221 				break;
222 			}
223 			if (InChild)
224 			{
225 				errno = 0;
226 				syserr("Nested MAIL command");
227 				exit(0);
228 			}
229 
230 			/* fork a subprocess to process this command */
231 			if (runinchild("SMTP-MAIL") > 0)
232 				break;
233 			define('s', sendinghost, CurEnv);
234 			define('r', "SMTP", CurEnv);
235 			initsys();
236 			setproctitle("%s %s: %s", CurEnv->e_id,
237 				CurHostName, inp);
238 
239 			/* child -- go do the processing */
240 			p = skipword(p, "from");
241 			if (p == NULL)
242 				break;
243 			setsender(p);
244 			if (Errors == 0)
245 			{
246 				message("250", "Sender ok");
247 				hasmail = TRUE;
248 			}
249 			else if (InChild)
250 				finis();
251 			break;
252 
253 		  case CMDRCPT:		/* rcpt -- designate recipient */
254 			SmtpPhase = "RCPT";
255 			setproctitle("%s %s: %s", CurEnv->e_id,
256 				CurHostName, inp);
257 			if (setjmp(TopFrame) > 0)
258 			{
259 				CurEnv->e_flags &= ~EF_FATALERRS;
260 				break;
261 			}
262 			QuickAbort = TRUE;
263 			LogUsrErrs = TRUE;
264 			p = skipword(p, "to");
265 			if (p == NULL)
266 				break;
267 			a = parseaddr(p, (ADDRESS *) NULL, 1, '\0');
268 			if (a == NULL)
269 				break;
270 			a->q_flags |= QPRIMARY;
271 			a = recipient(a, &CurEnv->e_sendqueue);
272 			if (Errors != 0)
273 				break;
274 
275 			/* no errors during parsing, but might be a duplicate */
276 			CurEnv->e_to = p;
277 			if (!bitset(QBADADDR, a->q_flags))
278 				message("250", "Recipient ok");
279 			else
280 			{
281 				/* punt -- should keep message in ADDRESS.... */
282 				message("550", "Addressee unknown");
283 			}
284 			CurEnv->e_to = NULL;
285 			break;
286 
287 		  case CMDDATA:		/* data -- text of mail */
288 			SmtpPhase = "DATA";
289 			if (!hasmail)
290 			{
291 				message("503", "Need MAIL command");
292 				break;
293 			}
294 			else if (CurEnv->e_nrcpts <= 0)
295 			{
296 				message("503", "Need RCPT (recipient)");
297 				break;
298 			}
299 
300 			/* collect the text of the message */
301 			SmtpPhase = "collect";
302 			setproctitle("%s %s: %s", CurEnv->e_id,
303 				CurHostName, inp);
304 			collect(TRUE);
305 			if (Errors != 0)
306 				break;
307 
308 			/*
309 			**  Arrange to send to everyone.
310 			**	If sending to multiple people, mail back
311 			**		errors rather than reporting directly.
312 			**	In any case, don't mail back errors for
313 			**		anything that has happened up to
314 			**		now (the other end will do this).
315 			**	Truncate our transcript -- the mail has gotten
316 			**		to us successfully, and if we have
317 			**		to mail this back, it will be easier
318 			**		on the reader.
319 			**	Then send to everyone.
320 			**	Finally give a reply code.  If an error has
321 			**		already been given, don't mail a
322 			**		message back.
323 			**	We goose error returns by clearing error bit.
324 			*/
325 
326 			SmtpPhase = "delivery";
327 			if (CurEnv->e_nrcpts != 1)
328 			{
329 				HoldErrs = TRUE;
330 				ErrorMode = EM_MAIL;
331 			}
332 			CurEnv->e_flags &= ~EF_FATALERRS;
333 			CurEnv->e_xfp = freopen(queuename(CurEnv, 'x'), "w", CurEnv->e_xfp);
334 
335 			/* send to all recipients */
336 			sendall(CurEnv, SM_DEFAULT);
337 			CurEnv->e_to = NULL;
338 
339 			/* save statistics */
340 			markstats(CurEnv, (ADDRESS *) NULL);
341 
342 			/* issue success if appropriate and reset */
343 			if (Errors == 0 || HoldErrs)
344 				message("250", "Ok");
345 			else
346 				CurEnv->e_flags &= ~EF_FATALERRS;
347 
348 			/* if in a child, pop back to our parent */
349 			if (InChild)
350 				finis();
351 
352 			/* clean up a bit */
353 			hasmail = 0;
354 			dropenvelope(CurEnv);
355 			CurEnv = newenvelope(CurEnv);
356 			CurEnv->e_flags = BlankEnvelope.e_flags;
357 			break;
358 
359 		  case CMDRSET:		/* rset -- reset state */
360 			message("250", "Reset state");
361 			if (InChild)
362 				finis();
363 			break;
364 
365 		  case CMDVRFY:		/* vrfy -- verify address */
366 			if (runinchild("SMTP-VRFY") > 0)
367 				break;
368 			setproctitle("%s: %s", CurHostName, inp);
369 			vrfyqueue = NULL;
370 			QuickAbort = TRUE;
371 			sendtolist(p, (ADDRESS *) NULL, &vrfyqueue);
372 			if (Errors != 0)
373 			{
374 				if (InChild)
375 					finis();
376 				break;
377 			}
378 			while (vrfyqueue != NULL)
379 			{
380 				register ADDRESS *a = vrfyqueue->q_next;
381 				char *code;
382 
383 				while (a != NULL && bitset(QDONTSEND|QBADADDR, a->q_flags))
384 					a = a->q_next;
385 
386 				if (!bitset(QDONTSEND|QBADADDR, vrfyqueue->q_flags))
387 				{
388 					if (a != NULL)
389 						code = "250-";
390 					else
391 						code = "250";
392 					if (vrfyqueue->q_fullname == NULL)
393 						message(code, "<%s>", vrfyqueue->q_paddr);
394 					else
395 						message(code, "%s <%s>",
396 						    vrfyqueue->q_fullname, vrfyqueue->q_paddr);
397 				}
398 				else if (a == NULL)
399 					message("554", "Self destructive alias loop");
400 				vrfyqueue = a;
401 			}
402 			if (InChild)
403 				finis();
404 			break;
405 
406 		  case CMDHELP:		/* help -- give user info */
407 			help(p);
408 			break;
409 
410 		  case CMDNOOP:		/* noop -- do nothing */
411 			message("200", "OK");
412 			break;
413 
414 		  case CMDQUIT:		/* quit -- leave mail */
415 			message("221", "%s closing connection", MyHostName);
416 			if (InChild)
417 				ExitStat = EX_QUIT;
418 			finis();
419 
420 		  case CMDVERB:		/* set verbose mode */
421 			Verbose = TRUE;
422 			SendMode = SM_DELIVER;
423 			message("200", "Verbose mode");
424 			break;
425 
426 		  case CMDONEX:		/* doing one transaction only */
427 			OneXact = TRUE;
428 			message("200", "Only one transaction");
429 			break;
430 
431 # ifdef SMTPDEBUG
432 		  case CMDDBGQSHOW:	/* show queues */
433 			printf("Send Queue=");
434 			printaddr(CurEnv->e_sendqueue, TRUE);
435 			break;
436 
437 		  case CMDDBGDEBUG:	/* set debug mode */
438 			tTsetup(tTdvect, sizeof tTdvect, "0-99.1");
439 			tTflag(p);
440 			message("200", "Debug set");
441 			break;
442 
443 # else /* not SMTPDEBUG */
444 
445 		  case CMDDBGQSHOW:	/* show queues */
446 		  case CMDDBGDEBUG:	/* set debug mode */
447 # ifdef LOG
448 			if (RealHostName != NULL && LogLevel > 0)
449 				syslog(LOG_NOTICE,
450 				    "\"%s\" command from %s (%s)\n",
451 				    c->cmdname, RealHostName,
452 				    inet_ntoa(RealHostAddr.sin_addr));
453 # endif
454 			/* FALL THROUGH */
455 # endif /* SMTPDEBUG */
456 
457 		  case CMDERROR:	/* unknown command */
458 			message("500", "Command unrecognized");
459 			break;
460 
461 		  default:
462 			errno = 0;
463 			syserr("smtp: unknown code %d", c->cmdcode);
464 			break;
465 		}
466 	}
467 }
468 /*
469 **  SKIPWORD -- skip a fixed word.
470 **
471 **	Parameters:
472 **		p -- place to start looking.
473 **		w -- word to skip.
474 **
475 **	Returns:
476 **		p following w.
477 **		NULL on error.
478 **
479 **	Side Effects:
480 **		clobbers the p data area.
481 */
482 
483 static char *
484 skipword(p, w)
485 	register char *p;
486 	char *w;
487 {
488 	register char *q;
489 
490 	/* find beginning of word */
491 	while (isspace(*p))
492 		p++;
493 	q = p;
494 
495 	/* find end of word */
496 	while (*p != '\0' && *p != ':' && !isspace(*p))
497 		p++;
498 	while (isspace(*p))
499 		*p++ = '\0';
500 	if (*p != ':')
501 	{
502 	  syntax:
503 		message("501", "Syntax error");
504 		Errors++;
505 		return (NULL);
506 	}
507 	*p++ = '\0';
508 	while (isspace(*p))
509 		p++;
510 
511 	/* see if the input word matches desired word */
512 	if (strcasecmp(q, w))
513 		goto syntax;
514 
515 	return (p);
516 }
517 /*
518 **  HELP -- implement the HELP command.
519 **
520 **	Parameters:
521 **		topic -- the topic we want help for.
522 **
523 **	Returns:
524 **		none.
525 **
526 **	Side Effects:
527 **		outputs the help file to message output.
528 */
529 
530 help(topic)
531 	char *topic;
532 {
533 	register FILE *hf;
534 	int len;
535 	char buf[MAXLINE];
536 	bool noinfo;
537 
538 	if (HelpFile == NULL || (hf = fopen(HelpFile, "r")) == NULL)
539 	{
540 		/* no help */
541 		errno = 0;
542 		message("502", "HELP not implemented");
543 		return;
544 	}
545 
546 	if (topic == NULL || *topic == '\0')
547 		topic = "smtp";
548 	else
549 		makelower(topic);
550 
551 	len = strlen(topic);
552 	noinfo = TRUE;
553 
554 	while (fgets(buf, sizeof buf, hf) != NULL)
555 	{
556 		if (strncmp(buf, topic, len) == 0)
557 		{
558 			register char *p;
559 
560 			p = index(buf, '\t');
561 			if (p == NULL)
562 				p = buf;
563 			else
564 				p++;
565 			fixcrlf(p, TRUE);
566 			message("214-", p);
567 			noinfo = FALSE;
568 		}
569 	}
570 
571 	if (noinfo)
572 		message("504", "HELP topic unknown");
573 	else
574 		message("214", "End of HELP info");
575 	(void) fclose(hf);
576 }
577 /*
578 **  RUNINCHILD -- return twice -- once in the child, then in the parent again
579 **
580 **	Parameters:
581 **		label -- a string used in error messages
582 **
583 **	Returns:
584 **		zero in the child
585 **		one in the parent
586 **
587 **	Side Effects:
588 **		none.
589 */
590 
591 runinchild(label)
592 	char *label;
593 {
594 	int childpid;
595 
596 	if (!OneXact)
597 	{
598 		childpid = dofork();
599 		if (childpid < 0)
600 		{
601 			syserr("%s: cannot fork", label);
602 			return (1);
603 		}
604 		if (childpid > 0)
605 		{
606 			auto int st;
607 
608 			/* parent -- wait for child to complete */
609 			st = waitfor(childpid);
610 			if (st == -1)
611 				syserr("%s: lost child", label);
612 
613 			/* if we exited on a QUIT command, complete the process */
614 			if (st == (EX_QUIT << 8))
615 				finis();
616 
617 			return (1);
618 		}
619 		else
620 		{
621 			/* child */
622 			InChild = TRUE;
623 			QuickAbort = FALSE;
624 			clearenvelope(CurEnv, FALSE);
625 		}
626 	}
627 
628 	/* open alias database */
629 	initaliases(AliasFile, FALSE);
630 
631 	return (0);
632 }
633 
634 # endif SMTP
635