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	6.4 (Berkeley) 02/14/93 (with SMTP)";
14 #else
15 static char sccsid[] = "@(#)srvrsmtp.c	6.4 (Berkeley) 02/14/93 (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 		RealHostName = MyHostName;
118 	CurHostName = RealHostName;
119 	setproctitle("srvrsmtp %s", CurHostName);
120 	expand("\001e", inp, &inp[sizeof inp], e);
121 	message("220", "%s", inp);
122 	SmtpPhase = "startup";
123 	sendinghost = NULL;
124 	for (;;)
125 	{
126 		/* arrange for backout */
127 		if (setjmp(TopFrame) > 0 && InChild)
128 			finis();
129 		QuickAbort = FALSE;
130 		HoldErrs = FALSE;
131 		LogUsrErrs = FALSE;
132 
133 		/* setup for the read */
134 		e->e_to = NULL;
135 		Errors = 0;
136 		(void) fflush(stdout);
137 
138 		/* read the input line */
139 		p = sfgets(inp, sizeof inp, InChannel, ReadTimeout);
140 
141 		/* handle errors */
142 		if (p == NULL)
143 		{
144 			/* end of file, just die */
145 			message("421", "%s Lost input channel from %s",
146 				MyHostName, CurHostName);
147 #ifdef LOG
148 			if (LogLevel >= 4)
149 				syslog(LOG_NOTICE, "lost input channel from %s",
150 					CurHostName);
151 #endif
152 			finis();
153 		}
154 
155 		/* clean up end of line */
156 		fixcrlf(inp, TRUE);
157 
158 		/* echo command to transcript */
159 		if (e->e_xfp != NULL)
160 			fprintf(e->e_xfp, "<<< %s\n", inp);
161 
162 		/* break off command */
163 		for (p = inp; isspace(*p); p++)
164 			continue;
165 		cmd = cmdbuf;
166 		while (*p != '\0' && !isspace(*p) && cmd < &cmdbuf[sizeof cmdbuf - 2])
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 		/* reset errors */
182 		errno = 0;
183 
184 		/* process command */
185 		switch (c->cmdcode)
186 		{
187 		  case CMDHELO:		/* hello -- introduce yourself */
188 			SmtpPhase = "HELO";
189 			setproctitle("%s: %s", CurHostName, inp);
190 			if (!strcasecmp(p, MyHostName))
191 			{
192 				/*
193 				 * didn't know about alias,
194 				 * or connected to an echo server
195 				 */
196 				message("553", "%s config error: mail loops back to myself",
197 					MyHostName);
198 				break;
199 			}
200 			if (RealHostName != NULL && strcasecmp(p, RealHostName))
201 			{
202 				char hostbuf[MAXNAME];
203 
204 				(void) sprintf(hostbuf, "%s (%s)", p, RealHostName);
205 				sendinghost = newstr(hostbuf);
206 			}
207 			else
208 				sendinghost = newstr(p);
209 			message("250", "%s Hello %s, pleased to meet you",
210 				MyHostName, sendinghost);
211 			break;
212 
213 		  case CMDMAIL:		/* mail -- designate sender */
214 			SmtpPhase = "MAIL";
215 
216 			/* force a sending host even if no HELO given */
217 			if (RealHostName != NULL && macvalue('s', e) == NULL)
218 				sendinghost = RealHostName;
219 
220 			/* check for validity of this command */
221 			if (hasmail)
222 			{
223 				message("503", "Sender already specified");
224 				break;
225 			}
226 			if (InChild)
227 			{
228 				errno = 0;
229 				syserr("Nested MAIL command");
230 				exit(0);
231 			}
232 
233 			/* fork a subprocess to process this command */
234 			if (runinchild("SMTP-MAIL", e) > 0)
235 				break;
236 			define('s', sendinghost, e);
237 			define('r', "SMTP", e);
238 			initsys(e);
239 			setproctitle("%s %s: %s", e->e_id, CurHostName, inp);
240 
241 			/* child -- go do the processing */
242 			p = skipword(p, "from");
243 			if (p == NULL)
244 				break;
245 			if (setjmp(TopFrame) > 0)
246 				break;
247 			QuickAbort = TRUE;
248 			setsender(p, e);
249 			if (Errors == 0)
250 			{
251 				message("250", "Sender ok");
252 				hasmail = TRUE;
253 			}
254 			else if (InChild)
255 				finis();
256 			break;
257 
258 		  case CMDRCPT:		/* rcpt -- designate recipient */
259 			SmtpPhase = "RCPT";
260 			setproctitle("%s %s: %s", e->e_id, 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, CurHostName, inp);
307 			collect(TRUE, e);
308 			if (Errors != 0)
309 				break;
310 
311 			/*
312 			**  Arrange to send to everyone.
313 			**	If sending to multiple people, mail back
314 			**		errors rather than reporting directly.
315 			**	In any case, don't mail back errors for
316 			**		anything that has happened up to
317 			**		now (the other end will do this).
318 			**	Truncate our transcript -- the mail has gotten
319 			**		to us successfully, and if we have
320 			**		to mail this back, it will be easier
321 			**		on the reader.
322 			**	Then send to everyone.
323 			**	Finally give a reply code.  If an error has
324 			**		already been given, don't mail a
325 			**		message back.
326 			**	We goose error returns by clearing error bit.
327 			*/
328 
329 			SmtpPhase = "delivery";
330 			if (e->e_nrcpts != 1)
331 			{
332 				HoldErrs = TRUE;
333 				ErrorMode = EM_MAIL;
334 			}
335 			e->e_flags &= ~EF_FATALERRS;
336 			e->e_xfp = freopen(queuename(e, 'x'), "w", e->e_xfp);
337 
338 			/* send to all recipients */
339 			sendall(e, SM_DEFAULT);
340 			e->e_to = NULL;
341 
342 			/* save statistics */
343 			markstats(e, (ADDRESS *) NULL);
344 
345 			/* issue success if appropriate and reset */
346 			if (Errors == 0 || HoldErrs)
347 				message("250", "Ok");
348 			else
349 				e->e_flags &= ~EF_FATALERRS;
350 
351 			/* if in a child, pop back to our parent */
352 			if (InChild)
353 				finis();
354 
355 			/* clean up a bit */
356 			hasmail = 0;
357 			dropenvelope(e);
358 			CurEnv = e = newenvelope(e);
359 			e->e_flags = BlankEnvelope.e_flags;
360 			break;
361 
362 		  case CMDRSET:		/* rset -- reset state */
363 			message("250", "Reset state");
364 			if (InChild)
365 				finis();
366 			break;
367 
368 		  case CMDVRFY:		/* vrfy -- verify address */
369 			if (runinchild("SMTP-VRFY", e) > 0)
370 				break;
371 			setproctitle("%s: %s", CurHostName, inp);
372 #ifdef LOG
373 			if (LogLevel >= 9)
374 				syslog(LOG_INFO, "%s: %s", CurHostName, inp);
375 #endif
376 			vrfyqueue = NULL;
377 			QuickAbort = TRUE;
378 			sendtolist(p, (ADDRESS *) NULL, &vrfyqueue, e);
379 			if (Errors != 0)
380 			{
381 				if (InChild)
382 					finis();
383 				break;
384 			}
385 			while (vrfyqueue != NULL)
386 			{
387 				register ADDRESS *a = vrfyqueue->q_next;
388 				char *code;
389 
390 				while (a != NULL && bitset(QDONTSEND|QBADADDR, a->q_flags))
391 					a = a->q_next;
392 
393 				if (!bitset(QDONTSEND|QBADADDR, vrfyqueue->q_flags))
394 				{
395 					if (a != NULL)
396 						code = "250-";
397 					else
398 						code = "250";
399 					if (vrfyqueue->q_fullname == NULL)
400 						message(code, "<%s>", vrfyqueue->q_paddr);
401 					else
402 						message(code, "%s <%s>",
403 						    vrfyqueue->q_fullname, vrfyqueue->q_paddr);
404 				}
405 				else if (a == NULL)
406 					message("554", "Self destructive alias loop");
407 				vrfyqueue = a;
408 			}
409 			if (InChild)
410 				finis();
411 			break;
412 
413 		  case CMDHELP:		/* help -- give user info */
414 			help(p);
415 			break;
416 
417 		  case CMDNOOP:		/* noop -- do nothing */
418 			message("200", "OK");
419 			break;
420 
421 		  case CMDQUIT:		/* quit -- leave mail */
422 			message("221", "%s closing connection", MyHostName);
423 			if (InChild)
424 				ExitStat = EX_QUIT;
425 			finis();
426 
427 		  case CMDVERB:		/* set verbose mode */
428 			Verbose = TRUE;
429 			SendMode = SM_DELIVER;
430 			message("200", "Verbose mode");
431 			break;
432 
433 		  case CMDONEX:		/* doing one transaction only */
434 			OneXact = TRUE;
435 			message("200", "Only one transaction");
436 			break;
437 
438 # ifdef SMTPDEBUG
439 		  case CMDDBGQSHOW:	/* show queues */
440 			printf("Send Queue=");
441 			printaddr(e->e_sendqueue, TRUE);
442 			break;
443 
444 		  case CMDDBGDEBUG:	/* set debug mode */
445 			tTsetup(tTdvect, sizeof tTdvect, "0-99.1");
446 			tTflag(p);
447 			message("200", "Debug set");
448 			break;
449 
450 # else /* not SMTPDEBUG */
451 
452 		  case CMDDBGQSHOW:	/* show queues */
453 		  case CMDDBGDEBUG:	/* set debug mode */
454 # ifdef LOG
455 			if (RealHostName != NULL && LogLevel > 0)
456 				syslog(LOG_NOTICE,
457 				    "\"%s\" command from %s (%s)\n",
458 				    c->cmdname, RealHostName,
459 				    inet_ntoa(RealHostAddr.sin_addr));
460 # endif
461 			/* FALL THROUGH */
462 # endif /* SMTPDEBUG */
463 
464 		  case CMDERROR:	/* unknown command */
465 			message("500", "Command unrecognized");
466 			break;
467 
468 		  default:
469 			errno = 0;
470 			syserr("smtp: unknown code %d", c->cmdcode);
471 			break;
472 		}
473 	}
474 }
475 /*
476 **  SKIPWORD -- skip a fixed word.
477 **
478 **	Parameters:
479 **		p -- place to start looking.
480 **		w -- word to skip.
481 **
482 **	Returns:
483 **		p following w.
484 **		NULL on error.
485 **
486 **	Side Effects:
487 **		clobbers the p data area.
488 */
489 
490 static char *
491 skipword(p, w)
492 	register char *p;
493 	char *w;
494 {
495 	register char *q;
496 
497 	/* find beginning of word */
498 	while (isspace(*p))
499 		p++;
500 	q = p;
501 
502 	/* find end of word */
503 	while (*p != '\0' && *p != ':' && !isspace(*p))
504 		p++;
505 	while (isspace(*p))
506 		*p++ = '\0';
507 	if (*p != ':')
508 	{
509 	  syntax:
510 		message("501", "Syntax error");
511 		Errors++;
512 		return (NULL);
513 	}
514 	*p++ = '\0';
515 	while (isspace(*p))
516 		p++;
517 
518 	/* see if the input word matches desired word */
519 	if (strcasecmp(q, w))
520 		goto syntax;
521 
522 	return (p);
523 }
524 /*
525 **  HELP -- implement the HELP command.
526 **
527 **	Parameters:
528 **		topic -- the topic we want help for.
529 **
530 **	Returns:
531 **		none.
532 **
533 **	Side Effects:
534 **		outputs the help file to message output.
535 */
536 
537 help(topic)
538 	char *topic;
539 {
540 	register FILE *hf;
541 	int len;
542 	char buf[MAXLINE];
543 	bool noinfo;
544 
545 	if (HelpFile == NULL || (hf = fopen(HelpFile, "r")) == NULL)
546 	{
547 		/* no help */
548 		errno = 0;
549 		message("502", "HELP not implemented");
550 		return;
551 	}
552 
553 	if (topic == NULL || *topic == '\0')
554 		topic = "smtp";
555 	else
556 		makelower(topic);
557 
558 	len = strlen(topic);
559 	noinfo = TRUE;
560 
561 	while (fgets(buf, sizeof buf, hf) != NULL)
562 	{
563 		if (strncmp(buf, topic, len) == 0)
564 		{
565 			register char *p;
566 
567 			p = strchr(buf, '\t');
568 			if (p == NULL)
569 				p = buf;
570 			else
571 				p++;
572 			fixcrlf(p, TRUE);
573 			message("214-", p);
574 			noinfo = FALSE;
575 		}
576 	}
577 
578 	if (noinfo)
579 		message("504", "HELP topic unknown");
580 	else
581 		message("214", "End of HELP info");
582 	(void) fclose(hf);
583 }
584 /*
585 **  RUNINCHILD -- return twice -- once in the child, then in the parent again
586 **
587 **	Parameters:
588 **		label -- a string used in error messages
589 **
590 **	Returns:
591 **		zero in the child
592 **		one in the parent
593 **
594 **	Side Effects:
595 **		none.
596 */
597 
598 runinchild(label, e)
599 	char *label;
600 	register ENVELOPE *e;
601 {
602 	int childpid;
603 
604 	if (!OneXact)
605 	{
606 		childpid = dofork();
607 		if (childpid < 0)
608 		{
609 			syserr("%s: cannot fork", label);
610 			return (1);
611 		}
612 		if (childpid > 0)
613 		{
614 			auto int st;
615 
616 			/* parent -- wait for child to complete */
617 			st = waitfor(childpid);
618 			if (st == -1)
619 				syserr("%s: lost child", label);
620 
621 			/* if we exited on a QUIT command, complete the process */
622 			if (st == (EX_QUIT << 8))
623 				finis();
624 
625 			return (1);
626 		}
627 		else
628 		{
629 			/* child */
630 			InChild = TRUE;
631 			QuickAbort = FALSE;
632 			clearenvelope(e, FALSE);
633 		}
634 	}
635 
636 	/* open alias database */
637 	initaliases(AliasFile, FALSE, e);
638 
639 	return (0);
640 }
641 
642 # endif /* SMTP */
643