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	6.9 (Berkeley) 02/19/93 (with SMTP)";
14 #else
15 static char sccsid[] = "@(#)srvrsmtp.c	6.9 (Berkeley) 02/19/93 (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("\201e", 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 > 1)
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; isascii(*p) && isspace(*p); p++)
164 			continue;
165 		cmd = cmdbuf;
166 		while (*p != '\0' &&
167 		       !(isascii(*p) && isspace(*p)) &&
168 		       cmd < &cmdbuf[sizeof cmdbuf - 2])
169 			*cmd++ = *p++;
170 		*cmd = '\0';
171 
172 		/* throw away leading whitespace */
173 		while (isascii(*p) && isspace(*p))
174 			p++;
175 
176 		/* decode command */
177 		for (c = CmdTab; c->cmdname != NULL; c++)
178 		{
179 			if (!strcasecmp(c->cmdname, cmdbuf))
180 				break;
181 		}
182 
183 		/* reset errors */
184 		errno = 0;
185 
186 		/* process command */
187 		switch (c->cmdcode)
188 		{
189 		  case CMDHELO:		/* hello -- introduce yourself */
190 			SmtpPhase = "HELO";
191 			setproctitle("%s: %s", CurHostName, inp);
192 			if (!strcasecmp(p, MyHostName))
193 			{
194 				/*
195 				 * didn't know about alias,
196 				 * or connected to an echo server
197 				 */
198 				message("553", "%s config error: mail loops back to myself",
199 					MyHostName);
200 				break;
201 			}
202 			if (RealHostName != NULL && strcasecmp(p, RealHostName))
203 			{
204 				char hostbuf[MAXNAME];
205 
206 				(void) sprintf(hostbuf, "%s (%s)", p, RealHostName);
207 				sendinghost = newstr(hostbuf);
208 			}
209 			else
210 				sendinghost = newstr(p);
211 			message("250", "%s Hello %s, pleased to meet you",
212 				MyHostName, sendinghost);
213 			break;
214 
215 		  case CMDMAIL:		/* mail -- designate sender */
216 			SmtpPhase = "MAIL";
217 
218 			/* force a sending host even if no HELO given */
219 			if (sendinghost == NULL && macvalue('s', e) == NULL)
220 				sendinghost = RealHostName;
221 
222 			/* check for validity of this command */
223 			if (hasmail)
224 			{
225 				message("503", "Sender already specified");
226 				break;
227 			}
228 			if (InChild)
229 			{
230 				errno = 0;
231 				syserr("Nested MAIL command: MAIL %s", p);
232 				exit(0);
233 			}
234 
235 			/* fork a subprocess to process this command */
236 			if (runinchild("SMTP-MAIL", e) > 0)
237 				break;
238 			if (sendinghost != NULL)
239 				define('s', sendinghost, e);
240 			define('r', "SMTP", e);
241 			initsys(e);
242 			setproctitle("%s %s: %s", e->e_id, CurHostName, inp);
243 
244 			/* child -- go do the processing */
245 			p = skipword(p, "from");
246 			if (p == NULL)
247 				break;
248 			if (setjmp(TopFrame) > 0)
249 				break;
250 			QuickAbort = TRUE;
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 = FALSE;
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 > 5)
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 (strchr(vrfyqueue->q_paddr, '<') != NULL)
403 						message(code, "%s", vrfyqueue->q_paddr);
404 					else if (vrfyqueue->q_fullname == NULL)
405 						message(code, "<%s>", vrfyqueue->q_paddr);
406 					else
407 						message(code, "%s <%s>",
408 						    vrfyqueue->q_fullname, vrfyqueue->q_paddr);
409 				}
410 				else if (a == NULL)
411 					message("554", "Self destructive alias loop");
412 				vrfyqueue = a;
413 			}
414 			if (InChild)
415 				finis();
416 			break;
417 
418 		  case CMDHELP:		/* help -- give user info */
419 			help(p);
420 			break;
421 
422 		  case CMDNOOP:		/* noop -- do nothing */
423 			message("200", "OK");
424 			break;
425 
426 		  case CMDQUIT:		/* quit -- leave mail */
427 			message("221", "%s closing connection", MyHostName);
428 			if (InChild)
429 				ExitStat = EX_QUIT;
430 			finis();
431 
432 		  case CMDVERB:		/* set verbose mode */
433 			Verbose = TRUE;
434 			SendMode = SM_DELIVER;
435 			message("200", "Verbose mode");
436 			break;
437 
438 		  case CMDONEX:		/* doing one transaction only */
439 			OneXact = TRUE;
440 			message("200", "Only one transaction");
441 			break;
442 
443 # ifdef SMTPDEBUG
444 		  case CMDDBGQSHOW:	/* show queues */
445 			printf("Send Queue=");
446 			printaddr(e->e_sendqueue, TRUE);
447 			break;
448 
449 		  case CMDDBGDEBUG:	/* set debug mode */
450 			tTsetup(tTdvect, sizeof tTdvect, "0-99.1");
451 			tTflag(p);
452 			message("200", "Debug set");
453 			break;
454 
455 # else /* not SMTPDEBUG */
456 
457 		  case CMDDBGQSHOW:	/* show queues */
458 		  case CMDDBGDEBUG:	/* set debug mode */
459 # ifdef LOG
460 			if (RealHostName != NULL && LogLevel > 0)
461 				syslog(LOG_NOTICE,
462 				    "\"%s\" command from %s (%s)",
463 				    c->cmdname, RealHostName,
464 				    inet_ntoa(RealHostAddr.sin_addr));
465 # endif
466 			/* FALL THROUGH */
467 # endif /* SMTPDEBUG */
468 
469 		  case CMDERROR:	/* unknown command */
470 			message("500", "Command unrecognized");
471 			break;
472 
473 		  default:
474 			errno = 0;
475 			syserr("smtp: unknown code %d", c->cmdcode);
476 			break;
477 		}
478 	}
479 }
480 /*
481 **  SKIPWORD -- skip a fixed word.
482 **
483 **	Parameters:
484 **		p -- place to start looking.
485 **		w -- word to skip.
486 **
487 **	Returns:
488 **		p following w.
489 **		NULL on error.
490 **
491 **	Side Effects:
492 **		clobbers the p data area.
493 */
494 
495 static char *
496 skipword(p, w)
497 	register char *p;
498 	char *w;
499 {
500 	register char *q;
501 
502 	/* find beginning of word */
503 	while (isascii(*p) && isspace(*p))
504 		p++;
505 	q = p;
506 
507 	/* find end of word */
508 	while (*p != '\0' && *p != ':' && !(isascii(*p) && isspace(*p)))
509 		p++;
510 	while (isascii(*p) && isspace(*p))
511 		*p++ = '\0';
512 	if (*p != ':')
513 	{
514 	  syntax:
515 		message("501", "Syntax error");
516 		Errors++;
517 		return (NULL);
518 	}
519 	*p++ = '\0';
520 	while (isascii(*p) && isspace(*p))
521 		p++;
522 
523 	/* see if the input word matches desired word */
524 	if (strcasecmp(q, w))
525 		goto syntax;
526 
527 	return (p);
528 }
529 /*
530 **  HELP -- implement the HELP command.
531 **
532 **	Parameters:
533 **		topic -- the topic we want help for.
534 **
535 **	Returns:
536 **		none.
537 **
538 **	Side Effects:
539 **		outputs the help file to message output.
540 */
541 
542 help(topic)
543 	char *topic;
544 {
545 	register FILE *hf;
546 	int len;
547 	char buf[MAXLINE];
548 	bool noinfo;
549 
550 	if (HelpFile == NULL || (hf = fopen(HelpFile, "r")) == NULL)
551 	{
552 		/* no help */
553 		errno = 0;
554 		message("502", "HELP not implemented");
555 		return;
556 	}
557 
558 	if (topic == NULL || *topic == '\0')
559 		topic = "smtp";
560 	else
561 		makelower(topic);
562 
563 	len = strlen(topic);
564 	noinfo = TRUE;
565 
566 	while (fgets(buf, sizeof buf, hf) != NULL)
567 	{
568 		if (strncmp(buf, topic, len) == 0)
569 		{
570 			register char *p;
571 
572 			p = strchr(buf, '\t');
573 			if (p == NULL)
574 				p = buf;
575 			else
576 				p++;
577 			fixcrlf(p, TRUE);
578 			message("214-", p);
579 			noinfo = FALSE;
580 		}
581 	}
582 
583 	if (noinfo)
584 		message("504", "HELP topic unknown");
585 	else
586 		message("214", "End of HELP info");
587 	(void) fclose(hf);
588 }
589 /*
590 **  RUNINCHILD -- return twice -- once in the child, then in the parent again
591 **
592 **	Parameters:
593 **		label -- a string used in error messages
594 **
595 **	Returns:
596 **		zero in the child
597 **		one in the parent
598 **
599 **	Side Effects:
600 **		none.
601 */
602 
603 runinchild(label, e)
604 	char *label;
605 	register ENVELOPE *e;
606 {
607 	int childpid;
608 
609 	if (!OneXact)
610 	{
611 		childpid = dofork();
612 		if (childpid < 0)
613 		{
614 			syserr("%s: cannot fork", label);
615 			return (1);
616 		}
617 		if (childpid > 0)
618 		{
619 			auto int st;
620 
621 			/* parent -- wait for child to complete */
622 			st = waitfor(childpid);
623 			if (st == -1)
624 				syserr("%s: lost child", label);
625 
626 			/* if we exited on a QUIT command, complete the process */
627 			if (st == (EX_QUIT << 8))
628 				finis();
629 
630 			return (1);
631 		}
632 		else
633 		{
634 			/* child */
635 			InChild = TRUE;
636 			QuickAbort = FALSE;
637 			clearenvelope(e, FALSE);
638 		}
639 	}
640 
641 	/* open alias database */
642 	initaliases(AliasFile, FALSE, e);
643 
644 	return (0);
645 }
646 
647 # endif /* SMTP */
648