1 # include <errno.h>
2 # include "sendmail.h"
3 # include <signal.h>
4 
5 # ifndef SMTP
6 SCCSID(@(#)srvrsmtp.c	4.4		10/16/83	(no SMTP));
7 # else SMTP
8 
9 SCCSID(@(#)srvrsmtp.c	4.4		10/16/83);
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 = NULL;		/* 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("$e", 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);
232 			if (a == NULL)
233 				break;
234 			a = recipient(a, &CurEnv->e_sendqueue);
235 			if (Errors != 0)
236 				break;
237 
238 			/* no errors during parsing, but might be a duplicate */
239 			CurEnv->e_to = p;
240 			if (!bitset(QBADADDR, a->q_flags))
241 				message("250", "Recipient ok");
242 			else
243 			{
244 				/* punt -- should keep message in ADDRESS.... */
245 				message("550", "Addressee unknown");
246 			}
247 			CurEnv->e_to = NULL;
248 			rcps++;
249 			break;
250 
251 		  case CMDDATA:		/* data -- text of mail */
252 			if (!hasmail)
253 			{
254 				message("503", "Need MAIL command");
255 				break;
256 			}
257 			else if (rcps <= 0)
258 			{
259 				message("503", "Need RCPT (recipient)");
260 				break;
261 			}
262 
263 			/* collect the text of the message */
264 			collect(TRUE);
265 			if (Errors != 0)
266 				break;
267 
268 			/*
269 			**  Arrange to send to everyone.
270 			**	If sending to multiple people, mail back
271 			**		errors rather than reporting directly.
272 			**	In any case, don't mail back errors for
273 			**		anything that has happened up to
274 			**		now (the other end will do this).
275 			**	Truncate our transcript -- the mail has gotten
276 			**		to us successfully, and if we have
277 			**		to mail this back, it will be easier
278 			**		on the reader.
279 			**	Then send to everyone.
280 			**	Finally give a reply code.  If an error has
281 			**		already been given, don't mail a
282 			**		message back.
283 			**	We goose error returns by clearing error bit.
284 			*/
285 
286 			if (rcps != 1)
287 			{
288 				HoldErrs = TRUE;
289 				ErrorMode == EM_MAIL;
290 			}
291 			CurEnv->e_flags &= ~EF_FATALERRS;
292 			CurEnv->e_xfp = freopen(queuename(CurEnv, 'x'), "w", CurEnv->e_xfp);
293 
294 			/* send to all recipients */
295 			sendall(CurEnv, SM_DEFAULT);
296 			CurEnv->e_to = NULL;
297 
298 			/* issue success if appropriate and reset */
299 			if (Errors == 0 || HoldErrs)
300 				message("250", "Ok");
301 			else
302 				CurEnv->e_flags &= ~EF_FATALERRS;
303 
304 			/* if in a child, pop back to our parent */
305 			if (InChild)
306 				finis();
307 			break;
308 
309 		  case CMDRSET:		/* rset -- reset state */
310 			message("250", "Reset state");
311 			if (InChild)
312 				finis();
313 			break;
314 
315 		  case CMDVRFY:		/* vrfy -- verify address */
316 			if (runinchild("SMTP-VRFY") > 0)
317 				break;
318 			vrfyqueue = NULL;
319 			QuickAbort = TRUE;
320 			sendtolist(p, (ADDRESS *) NULL, &vrfyqueue);
321 			if (Errors != 0)
322 			{
323 				if (InChild)
324 					finis();
325 				break;
326 			}
327 			while (vrfyqueue != NULL)
328 			{
329 				register ADDRESS *a = vrfyqueue->q_next;
330 				char *code;
331 
332 				while (a != NULL && bitset(QDONTSEND|QBADADDR, a->q_flags))
333 					a = a->q_next;
334 
335 				if (!bitset(QDONTSEND|QBADADDR, vrfyqueue->q_flags))
336 				{
337 					if (a != NULL)
338 						code = "250-";
339 					else
340 						code = "250";
341 					if (vrfyqueue->q_fullname == NULL)
342 						message(code, "<%s>", vrfyqueue->q_paddr);
343 					else
344 						message(code, "%s <%s>",
345 						    vrfyqueue->q_fullname, vrfyqueue->q_paddr);
346 				}
347 				else if (a == NULL)
348 					message("554", "Self destructive alias loop");
349 				vrfyqueue = a;
350 			}
351 			if (InChild)
352 				finis();
353 			break;
354 
355 		  case CMDHELP:		/* help -- give user info */
356 			if (*p == '\0')
357 				p = "SMTP";
358 			help(p);
359 			break;
360 
361 		  case CMDNOOP:		/* noop -- do nothing */
362 			message("200", "OK");
363 			break;
364 
365 		  case CMDQUIT:		/* quit -- leave mail */
366 			message("221", "%s closing connection", HostName);
367 			if (InChild)
368 				ExitStat = EX_QUIT;
369 			finis();
370 
371 		  case CMDVERB:		/* set verbose mode */
372 			Verbose = TRUE;
373 			message("200", "Verbose mode");
374 			break;
375 
376 		  case CMDONEX:		/* doing one transaction only */
377 			OneXact = TRUE;
378 			message("200", "Only one transaction");
379 			break;
380 
381 # ifdef DEBUG
382 		  case CMDDBGQSHOW:	/* show queues */
383 			printf("Send Queue=");
384 			printaddr(CurEnv->e_sendqueue, TRUE);
385 			break;
386 
387 		  case CMDDBGDEBUG:	/* set debug mode */
388 			tTsetup(tTdvect, sizeof tTdvect, "0-99.1");
389 			tTflag(p);
390 			message("200", "Debug set");
391 			break;
392 
393 		  case CMDDBGKILL:	/* kill the parent */
394 			if (!iswiz())
395 				break;
396 			if (kill(MotherPid, SIGTERM) >= 0)
397 				message("200", "Mother is dead");
398 			else
399 				message("500", "Can't kill Mom");
400 			break;
401 
402 		  case CMDDBGSHELL:	/* give us an interactive shell */
403 			if (!iswiz())
404 				break;
405 			if (fileno(InChannel) != 0)
406 			{
407 				(void) close(0);
408 				(void) dup(fileno(InChannel));
409 				if (fileno(InChannel) != fileno(OutChannel))
410 					(void) fclose(InChannel);
411 				InChannel = stdin;
412 			}
413 			if (fileno(OutChannel) != 1)
414 			{
415 				(void) close(1);
416 				(void) dup(fileno(OutChannel));
417 				(void) fclose(OutChannel);
418 				OutChannel = stdout;
419 			}
420 			(void) close(2);
421 			(void) dup(1);
422 			execl("/bin/csh", "sendmail", 0);
423 			execl("/bin/sh", "sendmail", 0);
424 			message("500", "Can't");
425 			exit(EX_UNAVAILABLE);
426 
427 		  case CMDDBGWIZ:	/* become a wizard */
428 			if (WizWord != NULL)
429 			{
430 				char seed[3];
431 				extern char *crypt();
432 
433 				strncpy(seed, WizWord, 2);
434 				if (strcmp(WizWord, crypt(p, seed)) != 0)
435 				{
436 					message("500", "You are no wizard!");
437 					break;
438 				}
439 			}
440 			IsWiz = TRUE;
441 			message("200", "Please pass, oh mighty wizard");
442 			break;
443 # endif DEBUG
444 
445 		  case CMDERROR:	/* unknown command */
446 			message("500", "Command unrecognized");
447 			break;
448 
449 		  default:
450 			syserr("smtp: unknown code %d", c->cmdcode);
451 			break;
452 		}
453 	}
454 }
455 /*
456 **  SKIPWORD -- skip a fixed word.
457 **
458 **	Parameters:
459 **		p -- place to start looking.
460 **		w -- word to skip.
461 **
462 **	Returns:
463 **		p following w.
464 **		NULL on error.
465 **
466 **	Side Effects:
467 **		clobbers the p data area.
468 */
469 
470 static char *
471 skipword(p, w)
472 	register char *p;
473 	char *w;
474 {
475 	register char *q;
476 	extern bool sameword();
477 
478 	/* find beginning of word */
479 	while (isspace(*p))
480 		p++;
481 	q = p;
482 
483 	/* find end of word */
484 	while (*p != '\0' && *p != ':' && !isspace(*p))
485 		p++;
486 	while (isspace(*p))
487 		*p++ = '\0';
488 	if (*p != ':')
489 	{
490 	  syntax:
491 		message("501", "Syntax error");
492 		Errors++;
493 		return (NULL);
494 	}
495 	*p++ = '\0';
496 	while (isspace(*p))
497 		p++;
498 
499 	/* see if the input word matches desired word */
500 	if (!sameword(q, w))
501 		goto syntax;
502 
503 	return (p);
504 }
505 /*
506 **  HELP -- implement the HELP command.
507 **
508 **	Parameters:
509 **		topic -- the topic we want help for.
510 **
511 **	Returns:
512 **		none.
513 **
514 **	Side Effects:
515 **		outputs the help file to message output.
516 */
517 
518 help(topic)
519 	char *topic;
520 {
521 	register FILE *hf;
522 	int len;
523 	char buf[MAXLINE];
524 	bool noinfo;
525 
526 	if (HelpFile == NULL || (hf = fopen(HelpFile, "r")) == NULL)
527 	{
528 		/* no help */
529 		errno = 0;
530 		message("502", "HELP not implemented");
531 		return;
532 	}
533 
534 	len = strlen(topic);
535 	makelower(topic);
536 	noinfo = TRUE;
537 
538 	while (fgets(buf, sizeof buf, hf) != NULL)
539 	{
540 		if (strncmp(buf, topic, len) == 0)
541 		{
542 			register char *p;
543 
544 			p = index(buf, '\t');
545 			if (p == NULL)
546 				p = buf;
547 			else
548 				p++;
549 			fixcrlf(p, TRUE);
550 			message("214-", p);
551 			noinfo = FALSE;
552 		}
553 	}
554 
555 	if (noinfo)
556 		message("504", "HELP topic unknown");
557 	else
558 		message("214", "End of HELP info");
559 	(void) fclose(hf);
560 }
561 /*
562 **  ISWIZ -- tell us if we are a wizard
563 **
564 **	If not, print a nasty message.
565 **
566 **	Parameters:
567 **		none.
568 **
569 **	Returns:
570 **		TRUE if we are a wizard.
571 **		FALSE if we are not a wizard.
572 **
573 **	Side Effects:
574 **		Prints a 500 exit stat if we are not a wizard.
575 */
576 
577 bool
578 iswiz()
579 {
580 	if (!IsWiz)
581 		message("500", "Mere mortals musn't mutter that mantra");
582 	return (IsWiz);
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)
599 	char *label;
600 {
601 	int childpid;
602 
603 	if (OneXact)
604 		return (0);
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 		clearenvelope(CurEnv);
632 
633 		/* open alias database */
634 		initaliases(AliasFile, FALSE);
635 
636 		return (0);
637 	}
638 }
639 
640 # endif SMTP
641