1 # include <errno.h>
2 # include "sendmail.h"
3 # include <signal.h>
4 
5 # ifndef SMTP
6 SCCSID(@(#)srvrsmtp.c	4.9		08/11/84	(no SMTP));
7 # else SMTP
8 
9 SCCSID(@(#)srvrsmtp.c	4.9		08/11/84);
10 
11 /*
12 **  SMTP -- run the SMTP protocol.
13 **
14 **	Parameters:
15 **		none.
16 **
17 **	Returns:
18 **		never.
19 **
20 **	Side Effects:
21 **		Reads commands from the input channel and processes
22 **			them.
23 */
24 
25 struct cmd
26 {
27 	char	*cmdname;	/* command name */
28 	int	cmdcode;	/* internal code, see below */
29 };
30 
31 /* values for cmdcode */
32 # define CMDERROR	0	/* bad command */
33 # define CMDMAIL	1	/* mail -- designate sender */
34 # define CMDRCPT	2	/* rcpt -- designate recipient */
35 # define CMDDATA	3	/* data -- send message text */
36 # define CMDRSET	4	/* rset -- reset state */
37 # define CMDVRFY	5	/* vrfy -- verify address */
38 # define CMDHELP	6	/* help -- give usage info */
39 # define CMDNOOP	7	/* noop -- do nothing */
40 # define CMDQUIT	8	/* quit -- close connection and die */
41 # define CMDHELO	9	/* helo -- be polite */
42 # define CMDDBGQSHOW	10	/* showq -- show send queue (DEBUG) */
43 # define CMDDBGDEBUG	11	/* debug -- set debug mode */
44 # define CMDVERB	12	/* verb -- go into verbose mode */
45 # define CMDDBGKILL	13	/* kill -- kill sendmail */
46 # define CMDDBGWIZ	14	/* wiz -- become a wizard */
47 # define CMDONEX	15	/* onex -- sending one transaction only */
48 # define CMDDBGSHELL	16	/* shell -- give us a shell */
49 
50 static struct cmd	CmdTab[] =
51 {
52 	"mail",		CMDMAIL,
53 	"rcpt",		CMDRCPT,
54 	"data",		CMDDATA,
55 	"rset",		CMDRSET,
56 	"vrfy",		CMDVRFY,
57 	"expn",		CMDVRFY,
58 	"help",		CMDHELP,
59 	"noop",		CMDNOOP,
60 	"quit",		CMDQUIT,
61 	"helo",		CMDHELO,
62 	"verb",		CMDVERB,
63 	"onex",		CMDONEX,
64 # ifdef DEBUG
65 	"showq",	CMDDBGQSHOW,
66 	"debug",	CMDDBGDEBUG,
67 	"kill",		CMDDBGKILL,
68 	"wiz",		CMDDBGWIZ,
69 	"shell",	CMDDBGSHELL,
70 # endif DEBUG
71 	NULL,		CMDERROR,
72 };
73 
74 # ifdef DEBUG
75 bool	IsWiz = FALSE;			/* set if we are a wizard */
76 char	*WizWord;			/* the wizard word to compare against */
77 # endif DEBUG
78 bool	InChild = FALSE;		/* true if running in a subprocess */
79 bool	OneXact = FALSE;		/* one xaction only this run */
80 char	*RealHostName = NULL;		/* verified hostname, set in daemon.c */
81 
82 #define EX_QUIT		22		/* special code for QUIT command */
83 
84 smtp()
85 {
86 	register char *p;
87 	register struct cmd *c;
88 	char *cmd;
89 	extern char *skipword();
90 	extern bool sameword();
91 	bool hasmail;			/* mail command received */
92 	int rcps;			/* number of recipients */
93 	auto ADDRESS *vrfyqueue;
94 	ADDRESS *a;
95 	char inp[MAXLINE];
96 	extern char Version[];
97 	extern tick();
98 	extern bool iswiz();
99 	extern char *arpadate();
100 	extern char *macvalue();
101 	extern ADDRESS *recipient();
102 
103 	hasmail = FALSE;
104 	rcps = 0;
105 	if (OutChannel != stdout)
106 	{
107 		/* arrange for debugging output to go to remote host */
108 		(void) close(1);
109 		(void) dup(fileno(OutChannel));
110 	}
111 	settime();
112 	expand("\001e", inp, &inp[sizeof inp], CurEnv);
113 	message("220", inp);
114 	for (;;)
115 	{
116 		/* arrange for backout */
117 		if (setjmp(TopFrame) > 0 && InChild)
118 			finis();
119 		QuickAbort = FALSE;
120 		HoldErrs = FALSE;
121 
122 		/* setup for the read */
123 		CurEnv->e_to = NULL;
124 		Errors = 0;
125 		(void) fflush(stdout);
126 
127 		/* read the input line */
128 		p = sfgets(inp, sizeof inp, InChannel);
129 
130 		/* handle errors */
131 		if (p == NULL)
132 		{
133 			/* end of file, just die */
134 			message("421", "%s Lost input channel", HostName);
135 			finis();
136 		}
137 
138 		/* clean up end of line */
139 		fixcrlf(inp, TRUE);
140 
141 		/* echo command to transcript */
142 		if (CurEnv->e_xfp != NULL)
143 			fprintf(CurEnv->e_xfp, "<<< %s\n", inp);
144 
145 		/* break off command */
146 		for (p = inp; isspace(*p); p++)
147 			continue;
148 		cmd = p;
149 		while (*++p != '\0' && !isspace(*p))
150 			continue;
151 		if (*p != '\0')
152 			*p++ = '\0';
153 
154 		/* decode command */
155 		for (c = CmdTab; c->cmdname != NULL; c++)
156 		{
157 			if (sameword(c->cmdname, cmd))
158 				break;
159 		}
160 
161 		/* process command */
162 		switch (c->cmdcode)
163 		{
164 		  case CMDHELO:		/* hello -- introduce yourself */
165 			if (sameword(p, HostName))
166 			{
167 				/* connected to an echo server */
168 				message("553", "%s I refuse to talk to myself",
169 					HostName);
170 				break;
171 			}
172 			if (RealHostName != NULL && !sameword(p, RealHostName))
173 			{
174 				char buf[MAXNAME];
175 
176 				(void) sprintf(buf, "%s (%s)", p, RealHostName);
177 				define('s', newstr(buf), CurEnv);
178 			}
179 			else
180 				define('s', newstr(p), CurEnv);
181 			message("250", "%s Hello %s, pleased to meet you",
182 				HostName, p);
183 			break;
184 
185 		  case CMDMAIL:		/* mail -- designate sender */
186 			/* force a sending host even if no HELO given */
187 			if (RealHostName != NULL && macvalue('s', CurEnv) == NULL)
188 				define('s', RealHostName, CurEnv);
189 
190 			/* check for validity of this command */
191 			if (hasmail)
192 			{
193 				message("503", "Sender already specified");
194 				break;
195 			}
196 			if (InChild)
197 			{
198 				syserr("Nested MAIL command");
199 				exit(0);
200 			}
201 
202 			/* fork a subprocess to process this command */
203 			if (runinchild("SMTP-MAIL") > 0)
204 				break;
205 			initsys();
206 
207 			/* child -- go do the processing */
208 			p = skipword(p, "from");
209 			if (p == NULL)
210 				break;
211 			setsender(p);
212 			if (Errors == 0)
213 			{
214 				message("250", "Sender ok");
215 				hasmail = TRUE;
216 			}
217 			else if (InChild)
218 				finis();
219 			break;
220 
221 		  case CMDRCPT:		/* rcpt -- designate recipient */
222 			if (setjmp(TopFrame) > 0)
223 			{
224 				CurEnv->e_flags &= ~EF_FATALERRS;
225 				break;
226 			}
227 			QuickAbort = TRUE;
228 			p = skipword(p, "to");
229 			if (p == NULL)
230 				break;
231 			a = parseaddr(p, (ADDRESS *) NULL, 1, '\0');
232 			if (a == NULL)
233 				break;
234 			a->q_flags |= QPRIMARY;
235 			a = recipient(a, &CurEnv->e_sendqueue);
236 			if (Errors != 0)
237 				break;
238 
239 			/* no errors during parsing, but might be a duplicate */
240 			CurEnv->e_to = p;
241 			if (!bitset(QBADADDR, a->q_flags))
242 				message("250", "Recipient ok");
243 			else
244 			{
245 				/* punt -- should keep message in ADDRESS.... */
246 				message("550", "Addressee unknown");
247 			}
248 			CurEnv->e_to = NULL;
249 			rcps++;
250 			break;
251 
252 		  case CMDDATA:		/* data -- text of mail */
253 			if (!hasmail)
254 			{
255 				message("503", "Need MAIL command");
256 				break;
257 			}
258 			else if (rcps <= 0)
259 			{
260 				message("503", "Need RCPT (recipient)");
261 				break;
262 			}
263 
264 			/* collect the text of the message */
265 			collect(TRUE);
266 			if (Errors != 0)
267 				break;
268 
269 			/*
270 			**  Arrange to send to everyone.
271 			**	If sending to multiple people, mail back
272 			**		errors rather than reporting directly.
273 			**	In any case, don't mail back errors for
274 			**		anything that has happened up to
275 			**		now (the other end will do this).
276 			**	Truncate our transcript -- the mail has gotten
277 			**		to us successfully, and if we have
278 			**		to mail this back, it will be easier
279 			**		on the reader.
280 			**	Then send to everyone.
281 			**	Finally give a reply code.  If an error has
282 			**		already been given, don't mail a
283 			**		message back.
284 			**	We goose error returns by clearing error bit.
285 			*/
286 
287 			if (rcps != 1)
288 			{
289 				HoldErrs = TRUE;
290 				ErrorMode = EM_MAIL;
291 			}
292 			CurEnv->e_flags &= ~EF_FATALERRS;
293 			CurEnv->e_xfp = freopen(queuename(CurEnv, 'x'), "w", CurEnv->e_xfp);
294 
295 			/* send to all recipients */
296 			sendall(CurEnv, SM_DEFAULT);
297 			CurEnv->e_to = NULL;
298 
299 			/* issue success if appropriate and reset */
300 			if (Errors == 0 || HoldErrs)
301 				message("250", "Ok");
302 			else
303 				CurEnv->e_flags &= ~EF_FATALERRS;
304 
305 			/* if in a child, pop back to our parent */
306 			if (InChild)
307 				finis();
308 			break;
309 
310 		  case CMDRSET:		/* rset -- reset state */
311 			message("250", "Reset state");
312 			if (InChild)
313 				finis();
314 			break;
315 
316 		  case CMDVRFY:		/* vrfy -- verify address */
317 			if (runinchild("SMTP-VRFY") > 0)
318 				break;
319 			vrfyqueue = NULL;
320 			QuickAbort = TRUE;
321 			sendtolist(p, (ADDRESS *) NULL, &vrfyqueue);
322 			if (Errors != 0)
323 			{
324 				if (InChild)
325 					finis();
326 				break;
327 			}
328 			while (vrfyqueue != NULL)
329 			{
330 				register ADDRESS *a = vrfyqueue->q_next;
331 				char *code;
332 
333 				while (a != NULL && bitset(QDONTSEND|QBADADDR, a->q_flags))
334 					a = a->q_next;
335 
336 				if (!bitset(QDONTSEND|QBADADDR, vrfyqueue->q_flags))
337 				{
338 					if (a != NULL)
339 						code = "250-";
340 					else
341 						code = "250";
342 					if (vrfyqueue->q_fullname == NULL)
343 						message(code, "<%s>", vrfyqueue->q_paddr);
344 					else
345 						message(code, "%s <%s>",
346 						    vrfyqueue->q_fullname, vrfyqueue->q_paddr);
347 				}
348 				else if (a == NULL)
349 					message("554", "Self destructive alias loop");
350 				vrfyqueue = a;
351 			}
352 			if (InChild)
353 				finis();
354 			break;
355 
356 		  case CMDHELP:		/* help -- give user info */
357 			if (*p == '\0')
358 				p = "SMTP";
359 			help(p);
360 			break;
361 
362 		  case CMDNOOP:		/* noop -- do nothing */
363 			message("200", "OK");
364 			break;
365 
366 		  case CMDQUIT:		/* quit -- leave mail */
367 			message("221", "%s closing connection", HostName);
368 			if (InChild)
369 				ExitStat = EX_QUIT;
370 			finis();
371 
372 		  case CMDVERB:		/* set verbose mode */
373 			Verbose = TRUE;
374 			message("200", "Verbose mode");
375 			break;
376 
377 		  case CMDONEX:		/* doing one transaction only */
378 			OneXact = TRUE;
379 			message("200", "Only one transaction");
380 			break;
381 
382 # ifdef DEBUG
383 		  case CMDDBGQSHOW:	/* show queues */
384 			printf("Send Queue=");
385 			printaddr(CurEnv->e_sendqueue, TRUE);
386 			break;
387 
388 		  case CMDDBGDEBUG:	/* set debug mode */
389 			tTsetup(tTdvect, sizeof tTdvect, "0-99.1");
390 			tTflag(p);
391 			message("200", "Debug set");
392 			break;
393 
394 		  case CMDDBGKILL:	/* kill the parent */
395 			if (!iswiz())
396 				break;
397 			if (kill(MotherPid, SIGTERM) >= 0)
398 				message("200", "Mother is dead");
399 			else
400 				message("500", "Can't kill Mom");
401 			break;
402 
403 		  case CMDDBGSHELL:	/* give us an interactive shell */
404 			if (!iswiz())
405 				break;
406 			if (fileno(InChannel) != 0)
407 			{
408 				(void) close(0);
409 				(void) dup(fileno(InChannel));
410 				if (fileno(InChannel) != fileno(OutChannel))
411 					(void) fclose(InChannel);
412 				InChannel = stdin;
413 			}
414 			if (fileno(OutChannel) != 1)
415 			{
416 				(void) close(1);
417 				(void) dup(fileno(OutChannel));
418 				(void) fclose(OutChannel);
419 				OutChannel = stdout;
420 			}
421 			(void) close(2);
422 			(void) dup(1);
423 			execl("/bin/csh", "sendmail", 0);
424 			execl("/bin/sh", "sendmail", 0);
425 			message("500", "Can't");
426 			exit(EX_UNAVAILABLE);
427 
428 		  case CMDDBGWIZ:	/* become a wizard */
429 			if (WizWord != NULL)
430 			{
431 				char seed[3];
432 				extern char *crypt();
433 
434 				strncpy(seed, WizWord, 2);
435 				if (strcmp(WizWord, crypt(p, seed)) == 0)
436 				{
437 					IsWiz = TRUE;
438 					message("200", "Please pass, oh mighty wizard");
439 					break;
440 				}
441 			}
442 			message("500", "You are no wizard!");
443 			break;
444 # endif DEBUG
445 
446 		  case CMDERROR:	/* unknown command */
447 			message("500", "Command unrecognized");
448 			break;
449 
450 		  default:
451 			syserr("smtp: unknown code %d", c->cmdcode);
452 			break;
453 		}
454 	}
455 }
456 /*
457 **  SKIPWORD -- skip a fixed word.
458 **
459 **	Parameters:
460 **		p -- place to start looking.
461 **		w -- word to skip.
462 **
463 **	Returns:
464 **		p following w.
465 **		NULL on error.
466 **
467 **	Side Effects:
468 **		clobbers the p data area.
469 */
470 
471 static char *
472 skipword(p, w)
473 	register char *p;
474 	char *w;
475 {
476 	register char *q;
477 	extern bool sameword();
478 
479 	/* find beginning of word */
480 	while (isspace(*p))
481 		p++;
482 	q = p;
483 
484 	/* find end of word */
485 	while (*p != '\0' && *p != ':' && !isspace(*p))
486 		p++;
487 	while (isspace(*p))
488 		*p++ = '\0';
489 	if (*p != ':')
490 	{
491 	  syntax:
492 		message("501", "Syntax error");
493 		Errors++;
494 		return (NULL);
495 	}
496 	*p++ = '\0';
497 	while (isspace(*p))
498 		p++;
499 
500 	/* see if the input word matches desired word */
501 	if (!sameword(q, w))
502 		goto syntax;
503 
504 	return (p);
505 }
506 /*
507 **  HELP -- implement the HELP command.
508 **
509 **	Parameters:
510 **		topic -- the topic we want help for.
511 **
512 **	Returns:
513 **		none.
514 **
515 **	Side Effects:
516 **		outputs the help file to message output.
517 */
518 
519 help(topic)
520 	char *topic;
521 {
522 	register FILE *hf;
523 	int len;
524 	char buf[MAXLINE];
525 	bool noinfo;
526 
527 	if (HelpFile == NULL || (hf = fopen(HelpFile, "r")) == NULL)
528 	{
529 		/* no help */
530 		errno = 0;
531 		message("502", "HELP not implemented");
532 		return;
533 	}
534 
535 	len = strlen(topic);
536 	makelower(topic);
537 	noinfo = TRUE;
538 
539 	while (fgets(buf, sizeof buf, hf) != NULL)
540 	{
541 		if (strncmp(buf, topic, len) == 0)
542 		{
543 			register char *p;
544 
545 			p = index(buf, '\t');
546 			if (p == NULL)
547 				p = buf;
548 			else
549 				p++;
550 			fixcrlf(p, TRUE);
551 			message("214-", p);
552 			noinfo = FALSE;
553 		}
554 	}
555 
556 	if (noinfo)
557 		message("504", "HELP topic unknown");
558 	else
559 		message("214", "End of HELP info");
560 	(void) fclose(hf);
561 }
562 /*
563 **  ISWIZ -- tell us if we are a wizard
564 **
565 **	If not, print a nasty message.
566 **
567 **	Parameters:
568 **		none.
569 **
570 **	Returns:
571 **		TRUE if we are a wizard.
572 **		FALSE if we are not a wizard.
573 **
574 **	Side Effects:
575 **		Prints a 500 exit stat if we are not a wizard.
576 */
577 
578 bool
579 iswiz()
580 {
581 	if (!IsWiz)
582 		message("500", "Mere mortals musn't mutter that mantra");
583 	return (IsWiz);
584 }
585 /*
586 **  RUNINCHILD -- return twice -- once in the child, then in the parent again
587 **
588 **	Parameters:
589 **		label -- a string used in error messages
590 **
591 **	Returns:
592 **		zero in the child
593 **		one in the parent
594 **
595 **	Side Effects:
596 **		none.
597 */
598 
599 runinchild(label)
600 	char *label;
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 		}
632 	}
633 
634 	/* child (or ONEX command specified) */
635 	clearenvelope(CurEnv);
636 
637 	/* open alias database */
638 	initaliases(AliasFile, FALSE);
639 
640 	return (0);
641 }
642 
643 # endif SMTP
644