1 /*
2  * Copyright (c) 2022 Omar Polo <op@omarpolo.com>
3  * Copyright (c) 2007-2016 Reyk Floeter <reyk@openbsd.org>
4  * Copyright (c) 2004, 2005 Esben Norby <norby@openbsd.org>
5  * Copyright (c) 2004 Ryan McBride <mcbride@openbsd.org>
6  * Copyright (c) 2002, 2003, 2004 Henning Brauer <henning@openbsd.org>
7  * Copyright (c) 2001 Markus Friedl.  All rights reserved.
8  * Copyright (c) 2001 Daniel Hartmeier.  All rights reserved.
9  * Copyright (c) 2001 Theo de Raadt.  All rights reserved.
10  *
11  * Permission to use, copy, modify, and distribute this software for any
12  * purpose with or without fee is hereby granted, provided that the above
13  * copyright notice and this permission notice appear in all copies.
14  *
15  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
16  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
17  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
18  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
19  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
20  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
21  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
22  */
23 
24 %{
25 #include <sys/types.h>
26 #include <sys/queue.h>
27 #include <sys/tree.h>
28 #include <sys/uio.h>
29 
30 #include <err.h>
31 #include <event.h>
32 #include <netdb.h>
33 #include <stdio.h>
34 #include <stdlib.h>
35 #include <limits.h>
36 #include <stdarg.h>
37 #include <stdint.h>
38 #include <string.h>
39 #include <unistd.h>
40 #include <ctype.h>
41 #include <errno.h>
42 #include <fcntl.h>
43 #include <pwd.h>
44 #include <imsg.h>
45 
46 #include "log.h"
47 #include "proc.h"
48 
49 #include "galileo.h"
50 
51 TAILQ_HEAD(files, file)		 files = TAILQ_HEAD_INITIALIZER(files);
52 static struct file {
53 	TAILQ_ENTRY(file)	 entry;
54 	FILE			*stream;
55 	char			*name;
56 	size_t			 ungetpos;
57 	size_t			 ungetsize;
58 	u_char			*ungetbuf;
59 	int			 eof_reached;
60 	int			 lineno;
61 	int			 errors;
62 } *file, *topfile;
63 struct file	*pushfile(const char *, int);
64 int		 popfile(void);
65 int		 yyparse(void);
66 int		 yylex(void);
67 int		 yyerror(const char *, ...)
68     __attribute__((__format__ (printf, 1, 2)))
69     __attribute__((__nonnull__ (1)));
70 int		 kw_cmp(const void *, const void *);
71 int		 lookup(char *);
72 int		 igetc(void);
73 int		 lgetc(int);
74 void		 lungetc(int);
75 int		 findeol(void);
76 
77 TAILQ_HEAD(symhead, sym)	 symhead = TAILQ_HEAD_INITIALIZER(symhead);
78 struct sym {
79 	TAILQ_ENTRY(sym)	 entry;
80 	int			 used;
81 	int			 persist;
82 	char			*nam;
83 	char			*val;
84 };
85 int		 symset(const char *, const char *, int);
86 char		*symget(const char *);
87 
88 int		 getservice(const char *);
89 
90 static struct galileo	*conf = NULL;
91 static struct proxy	*pr = NULL;
92 static int		 errors;
93 
94 typedef struct {
95 	union {
96 		int64_t		 number;
97 		char		*string;
98 	} v;
99 	int lineno;
100 } YYSTYPE;
101 
102 %}
103 
104 %token	INCLUDE ERROR
105 %token	CHROOT HOSTNAME PORT PREFORK PROXY SOURCE STYLESHEET
106 %type	<v.number>	NUMBER
107 %type	<v.number>	port
108 %type	<v.string>	STRING
109 %type	<v.string>	string
110 
111 %%
112 
113 grammar		: /* empty */
114 		| grammar include '\n'
115 		| grammar '\n'
116 		| grammar varset '\n'
117 		| grammar main '\n'
118 		| grammar proxy '\n'
119 		| grammar error '\n'		{ file->errors++; }
120 		;
121 
122 include		: INCLUDE string {
123 			struct file *nfile;
124 
125 			if ((nfile = pushfile($2, 0)) == NULL) {
126 				yyerror("failed to include file %s", $2);
127 				free($2);
128 				YYERROR;
129 			}
130 			free($2);
131 
132 			file = nfile;
133 			lungetc('\n');
134 		}
135 		;
136 
137 varset		: STRING '=' STRING {
138 			char *s = $1;
139 			while (*s++) {
140 				if (isspace((unsigned char)*s)) {
141 					yyerror("macro name cannot contain "
142 					    "whitespace");
143 					free($1);
144 					free($3);
145 					YYERROR;
146 				}
147 			}
148 			if (symset($1, $3, 0) == -1)
149 				fatalx("cannot store variable");
150 			free($1);
151 			free($3);
152 		}
153 		;
154 
155 main		: PREFORK NUMBER {
156 			if ($2 <= 0 || $2 > PROC_MAX_INSTANCES) {
157 				yyerror("invalid number of preforked "
158 				    "proxies: %lld", $2);
159 				YYERROR;
160 			}
161 			conf->sc_prefork = $2;
162 		}
163 		| CHROOT STRING {
164 			size_t n;
165 
166 			n = strlcpy(conf->sc_chroot, $2,
167 			    sizeof(conf->sc_chroot));
168 			if (n >= sizeof(conf->sc_chroot))
169 				yyerror("chroot path too long!");
170 			free($2);
171 		}
172 		;
173 
174 proxy		: PROXY STRING {
175 			struct proxy	*p;
176 			size_t		 n;
177 
178 			if ((p = calloc(1, sizeof(*p))) == NULL)
179 				fatal("calloc");
180 
181 			n = strlcpy(p->pr_conf.host, $2,
182 			    sizeof(p->pr_conf.host));
183 			if (n >= sizeof(p->pr_conf.host)) {
184 				yyerror("server name too long");
185 				free($2);
186 				free(p);
187 				YYERROR;
188 			}
189 			free($2);
190 
191 			pr = p;
192 			TAILQ_INSERT_TAIL(&conf->sc_proxies, p, pr_entry);
193 		} '{' optnl proxyopts_l '}' {
194 			/* check if duplicate */
195 
196 			if (*pr->pr_conf.proxy_addr == '\0')
197 				yyerror("missing source in proxy block `%s'",
198 				    pr->pr_conf.host);
199 
200 			pr = NULL;
201 		}
202 		;
203 
204 proxyopts_l	: proxyopts_l proxyoptsl nl
205 		| proxyoptsl optnl
206 		;
207 
208 proxyoptsl	: SOURCE STRING proxyport {
209 			size_t n;
210 
211 			n = strlcpy(pr->pr_conf.proxy_addr, $2,
212 			    sizeof(pr->pr_conf.proxy_addr));
213 			if (n >= sizeof(pr->pr_conf.proxy_addr))
214 				yyerror("proxy source too long!");
215 
216 			if (*pr->pr_conf.proxy_name == '\0') {
217 				n = strlcpy(pr->pr_conf.proxy_name, $2,
218 				    sizeof(pr->pr_conf.proxy_name));
219 				if (n >= sizeof(pr->pr_conf.proxy_name))
220 					yyerror("proxy hostname too long!");
221 			}
222 
223 			free($2);
224 		}
225 		| HOSTNAME STRING {
226 			size_t n;
227 
228 			n = strlcpy(pr->pr_conf.proxy_name, $2,
229 			    sizeof(pr->pr_conf.proxy_name));
230 			if (n >= sizeof(pr->pr_conf.proxy_name))
231 				yyerror("proxy hostname too long!");
232 			free($2);
233 		}
234 		| STYLESHEET string {
235 			size_t n;
236 
237 			n = strlcpy(pr->pr_conf.stylesheet, $2,
238 			    sizeof(pr->pr_conf.stylesheet));
239 			if (n >= sizeof(pr->pr_conf.stylesheet))
240 				yyerror("stylesheet path too long!");
241 			free($2);
242 		}
243 		;
244 
245 proxyport	: /* empty */ {
246 			strlcpy(pr->pr_conf.proxy_port, "1965",
247 			    sizeof(pr->pr_conf.proxy_port));
248 		}
249 		| PORT port {
250 			size_t len;
251 			int n;
252 
253 			len = sizeof(pr->pr_conf.proxy_port);
254 			n = snprintf(pr->pr_conf.proxy_port, len, "%lld", $2);
255 			if (n < 0 || (size_t)n >= len)
256 				fatal("port number too long?");
257 		};
258 
259 port		: NUMBER {
260 			if ($1 <= 0 || $1 > (int)USHRT_MAX) {
261 				yyerror("invalid port: %lld", $1);
262 				YYERROR;
263 			}
264 			$$ = $1;
265 		}
266 		| STRING {
267 			int val;
268 
269 			if ((val = getservice($1)) == -1) {
270 				yyerror("invalid port: %s", $1);
271 				free($1);
272 				YYERROR;
273 			}
274 			free($1);
275 			$$ = val;
276 		}
277 		;
278 
279 string		: STRING string {
280 			if (asprintf(&$$, "%s%s", $1, $2) == -1)
281 				fatal("asprintf string");
282 			free($1);
283 			free($2);
284 		}
285 		| STRING
286 		;
287 
288 optnl		: '\n' optnl
289 		|
290 		;
291 
292 nl		: '\n' optnl
293 		;
294 
295 %%
296 
297 struct keywords {
298 	const char	*k_name;
299 	int		 k_val;
300 };
301 
302 int
303 yyerror(const char *fmt, ...)
304 {
305 	va_list	 ap;
306 	char	*msg;
307 
308 	file->errors++;
309 	va_start(ap, fmt);
310 	if (vasprintf(&msg, fmt, ap) == -1)
311 		fatal("yyerror vasprintf");
312 	va_end(ap);
313 	log_warnx("%s:%d: %s", file->name, yylval.lineno, msg);
314 	free(msg);
315 	return (0);
316 }
317 
318 int
319 kw_cmp(const void *k, const void *e)
320 {
321 	return (strcmp(k, ((const struct keywords *)e)->k_name));
322 }
323 
324 int
325 lookup(char *s)
326 {
327 	/* this has to be sorted always */
328 	static const struct keywords keywords[] = {
329 		{ "chroot",	CHROOT },
330 		{ "hostname",	HOSTNAME },
331 		{ "include",	INCLUDE },
332 		{ "port",	PORT },
333 		{ "prefork",	PREFORK },
334 		{ "proxy",	PROXY },
335 		{ "source",	SOURCE },
336 		{ "stylesheet",	STYLESHEET},
337 	};
338 	const struct keywords	*p;
339 
340 	p = bsearch(s, keywords, nitems(keywords), sizeof(keywords[0]),
341 	    kw_cmp);
342 
343 	if (p)
344 		return (p->k_val);
345 	else
346 		return (STRING);
347 }
348 
349 #define START_EXPAND	1
350 #define DONE_EXPAND	2
351 
352 static int	expanding;
353 
354 int
355 igetc(void)
356 {
357 	int	c;
358 
359 	while (1) {
360 		if (file->ungetpos > 0)
361 			c = file->ungetbuf[--file->ungetpos];
362 		else
363 			c = getc(file->stream);
364 
365 		if (c == START_EXPAND)
366 			expanding = 1;
367 		else if (c == DONE_EXPAND)
368 			expanding = 0;
369 		else
370 			break;
371 	}
372 	return (c);
373 }
374 
375 int
376 lgetc(int quotec)
377 {
378 	int		c, next;
379 
380 	if (quotec) {
381 		if ((c = igetc()) == EOF) {
382 			yyerror("reached end of file while parsing "
383 			    "quoted string");
384 			if (file == topfile || popfile() == EOF)
385 				return (EOF);
386 			return (quotec);
387 		}
388 		return (c);
389 	}
390 
391 	while ((c = igetc()) == '\\') {
392 		next = igetc();
393 		if (next != '\n') {
394 			c = next;
395 			break;
396 		}
397 		yylval.lineno = file->lineno;
398 		file->lineno++;
399 	}
400 	if (c == '\t' || c == ' ') {
401 		/* Compress blanks to a single space. */
402 		do {
403 			c = getc(file->stream);
404 		} while (c == '\t' || c == ' ');
405 		ungetc(c, file->stream);
406 		c = ' ';
407 	}
408 
409 	if (c == EOF) {
410 		/*
411 		 * Fake EOL when hit EOF for the first time. This gets line
412 		 * count right if last line in included file is syntactically
413 		 * invalid and has no newline.
414 		 */
415 		if (file->eof_reached == 0) {
416 			file->eof_reached = 1;
417 			return ('\n');
418 		}
419 		while (c == EOF) {
420 			if (file == topfile || popfile() == EOF)
421 				return (EOF);
422 			c = igetc();
423 		}
424 	}
425 	return (c);
426 }
427 
428 void
429 lungetc(int c)
430 {
431 	if (c == EOF)
432 		return;
433 
434 	if (file->ungetpos >= file->ungetsize) {
435 		void *p = reallocarray(file->ungetbuf, file->ungetsize, 2);
436 		if (p == NULL)
437 			err(1, "%s", __func__);
438 		file->ungetbuf = p;
439 		file->ungetsize *= 2;
440 	}
441 	file->ungetbuf[file->ungetpos++] = c;
442 }
443 
444 int
445 findeol(void)
446 {
447 	int	c;
448 
449 	/* skip to either EOF or the first real EOL */
450 	while (1) {
451 		c = lgetc(0);
452 		if (c == '\n') {
453 			file->lineno++;
454 			break;
455 		}
456 		if (c == EOF)
457 			break;
458 	}
459 	return (ERROR);
460 }
461 
462 int
463 yylex(void)
464 {
465 	char	 buf[8096];
466 	char	*p, *val;
467 	int	 quotec, next, c;
468 	int	 token;
469 
470 top:
471 	p = buf;
472 	while ((c = lgetc(0)) == ' ' || c == '\t')
473 		; /* nothing */
474 
475 	yylval.lineno = file->lineno;
476 	if (c == '#')
477 		while ((c = lgetc(0)) != '\n' && c != EOF)
478 			; /* nothing */
479 	if (c == '$' && !expanding) {
480 		while (1) {
481 			if ((c = lgetc(0)) == EOF)
482 				return (0);
483 
484 			if (p + 1 >= buf + sizeof(buf) - 1) {
485 				yyerror("string too long");
486 				return (findeol());
487 			}
488 			if (isalnum(c) || c == '_') {
489 				*p++ = c;
490 				continue;
491 			}
492 			*p = '\0';
493 			lungetc(c);
494 			break;
495 		}
496 		val = symget(buf);
497 		if (val == NULL) {
498 			yyerror("macro '%s' not defined", buf);
499 			return (findeol());
500 		}
501 		p = val + strlen(val) - 1;
502 		lungetc(DONE_EXPAND);
503 		while (p >= val) {
504 			lungetc((unsigned char)*p);
505 			p--;
506 		}
507 		lungetc(START_EXPAND);
508 		goto top;
509 	}
510 
511 	switch (c) {
512 	case '\'':
513 	case '"':
514 		quotec = c;
515 		while (1) {
516 			if ((c = lgetc(quotec)) == EOF)
517 				return (0);
518 			if (c == '\n') {
519 				file->lineno++;
520 				continue;
521 			} else if (c == '\\') {
522 				if ((next = lgetc(quotec)) == EOF)
523 					return (0);
524 				if (next == quotec || next == ' ' ||
525 				    next == '\t')
526 					c = next;
527 				else if (next == '\n') {
528 					file->lineno++;
529 					continue;
530 				} else
531 					lungetc(next);
532 			} else if (c == quotec) {
533 				*p = '\0';
534 				break;
535 			} else if (c == '\0') {
536 				yyerror("syntax error");
537 				return (findeol());
538 			}
539 			if (p + 1 >= buf + sizeof(buf) - 1) {
540 				yyerror("string too long");
541 				return (findeol());
542 			}
543 			*p++ = c;
544 		}
545 		yylval.v.string = strdup(buf);
546 		if (yylval.v.string == NULL)
547 			fatal("yylex: strdup");
548 		return (STRING);
549 	}
550 
551 #define allowed_to_end_number(x) \
552 	(isspace(x) || x == ')' || x ==',' || x == '/' || x == '}' || x == '=')
553 
554 	if (c == '-' || isdigit(c)) {
555 		do {
556 			*p++ = c;
557 			if ((size_t)(p-buf) >= sizeof(buf)) {
558 				yyerror("string too long");
559 				return (findeol());
560 			}
561 		} while ((c = lgetc(0)) != EOF && isdigit(c));
562 		lungetc(c);
563 		if (p == buf + 1 && buf[0] == '-')
564 			goto nodigits;
565 		if (c == EOF || allowed_to_end_number(c)) {
566 			const char *errstr = NULL;
567 
568 			*p = '\0';
569 			yylval.v.number = strtonum(buf, LLONG_MIN,
570 			    LLONG_MAX, &errstr);
571 			if (errstr) {
572 				yyerror("\"%s\" invalid number: %s",
573 				    buf, errstr);
574 				return (findeol());
575 			}
576 			return (NUMBER);
577 		} else {
578 nodigits:
579 			while (p > buf + 1)
580 				lungetc((unsigned char)*--p);
581 			c = (unsigned char)*--p;
582 			if (c == '-')
583 				return (c);
584 		}
585 	}
586 
587 #define allowed_in_string(x) \
588 	(isalnum(x) || (ispunct(x) && x != '(' && x != ')' && \
589 	x != '{' && x != '}' && \
590 	x != '!' && x != '=' && x != '#' && \
591 	x != ','))
592 
593 	if (isalnum(c) || c == ':' || c == '_' || c == '/') {
594 		do {
595 			*p++ = c;
596 			if ((size_t)(p-buf) >= sizeof(buf)) {
597 				yyerror("string too long");
598 				return (findeol());
599 			}
600 		} while ((c = lgetc(0)) != EOF && (allowed_in_string(c)));
601 		lungetc(c);
602 		*p = '\0';
603 		if ((token = lookup(buf)) == STRING)
604 			if ((yylval.v.string = strdup(buf)) == NULL)
605 				fatal("yylex: strdup");
606 		return (token);
607 	}
608 	if (c == '\n') {
609 		yylval.lineno = file->lineno;
610 		file->lineno++;
611 	}
612 	if (c == EOF)
613 		return (0);
614 	return (c);
615 }
616 
617 struct file *
618 pushfile(const char *name, int secret)
619 {
620 	struct file	*nfile;
621 
622 	if ((nfile = calloc(1, sizeof(struct file))) == NULL) {
623 		log_warn("%s", __func__);
624 		return (NULL);
625 	}
626 	if ((nfile->name = strdup(name)) == NULL) {
627 		log_warn("%s", __func__);
628 		free(nfile);
629 		return (NULL);
630 	}
631 	if ((nfile->stream = fopen(nfile->name, "r")) == NULL) {
632 		free(nfile->name);
633 		free(nfile);
634 		return (NULL);
635 	}
636 	nfile->lineno = TAILQ_EMPTY(&files) ? 1 : 0;
637 	nfile->ungetsize = 16;
638 	nfile->ungetbuf = malloc(nfile->ungetsize);
639 	if (nfile->ungetbuf == NULL) {
640 		log_warn("%s", __func__);
641 		fclose(nfile->stream);
642 		free(nfile->name);
643 		free(nfile);
644 		return (NULL);
645 	}
646 	TAILQ_INSERT_TAIL(&files, nfile, entry);
647 	return (nfile);
648 }
649 
650 int
651 popfile(void)
652 {
653 	struct file	*prev;
654 
655 	if ((prev = TAILQ_PREV(file, files, entry)) != NULL)
656 		prev->errors += file->errors;
657 
658 	TAILQ_REMOVE(&files, file, entry);
659 	fclose(file->stream);
660 	free(file->name);
661 	free(file->ungetbuf);
662 	free(file);
663 	file = prev;
664 	return (file ? 0 : EOF);
665 }
666 
667 int
668 parse_config(const char *filename, struct galileo *env)
669 {
670 	struct sym	*sym, *next;
671 	size_t		 n;
672 
673 	conf = env;
674 
675 	n = strlcpy(conf->sc_conffile, filename, sizeof(conf->sc_conffile));
676 	if (n >= sizeof(conf->sc_conffile)) {
677 		log_warn("path too long: %s", filename);
678 		return (-1);
679 	}
680 
681 	if ((file = pushfile(filename, 0)) == NULL) {
682 		log_warn("failed to open %s", filename);
683 		return (-1);
684 	}
685 	topfile = file;
686 	setservent(1);
687 
688 	yyparse();
689 	errors = file->errors;
690 	popfile();
691 
692 	endservent();
693 
694 	/* Free macros and check which have not been used. */
695 	TAILQ_FOREACH_SAFE(sym, &symhead, entry, next) {
696 		if (!sym->used)
697 			fprintf(stderr, "warning: macro `%s' not used\n",
698 			    sym->nam);
699 		if (!sym->persist) {
700 			free(sym->nam);
701 			free(sym->val);
702 			TAILQ_REMOVE(&symhead, sym, entry);
703 			free(sym);
704 		}
705 	}
706 
707 	if (errors)
708 		return (-1);
709 
710 	return (0);
711 }
712 
713 int
714 symset(const char *nam, const char *val, int persist)
715 {
716 	struct sym	*sym;
717 
718 	TAILQ_FOREACH(sym, &symhead, entry) {
719 		if (strcmp(nam, sym->nam) == 0)
720 			break;
721 	}
722 
723 	if (sym != NULL) {
724 		if (sym->persist == 1)
725 			return (0);
726 		else {
727 			free(sym->nam);
728 			free(sym->val);
729 			TAILQ_REMOVE(&symhead, sym, entry);
730 			free(sym);
731 		}
732 	}
733 	if ((sym = calloc(1, sizeof(*sym))) == NULL)
734 		return (-1);
735 
736 	sym->nam = strdup(nam);
737 	if (sym->nam == NULL) {
738 		free(sym);
739 		return (-1);
740 	}
741 	sym->val = strdup(val);
742 	if (sym->val == NULL) {
743 		free(sym->nam);
744 		free(sym);
745 		return (-1);
746 	}
747 	sym->used = 0;
748 	sym->persist = persist;
749 	TAILQ_INSERT_TAIL(&symhead, sym, entry);
750 	return (0);
751 }
752 
753 int
754 cmdline_symset(char *s)
755 {
756 	char	*sym, *val;
757 	int	ret;
758 
759 	if ((val = strrchr(s, '=')) == NULL)
760 		return (-1);
761 	sym = strndup(s, val - s);
762 	if (sym == NULL)
763 		fatal("%s: strndup", __func__);
764 	ret = symset(sym, val + 1, 1);
765 	free(sym);
766 
767 	return (ret);
768 }
769 
770 char *
771 symget(const char *nam)
772 {
773 	struct sym	*sym;
774 
775 	TAILQ_FOREACH(sym, &symhead, entry) {
776 		if (strcmp(nam, sym->nam) == 0) {
777 			sym->used = 1;
778 			return (sym->val);
779 		}
780 	}
781 	return (NULL);
782 }
783 
784 int
785 getservice(const char *n)
786 {
787 	struct servent	*s;
788 	const char	*errstr;
789 	long long	 llval;
790 
791 	llval = strtonum(n, 0, UINT16_MAX, &errstr);
792 	if (errstr) {
793 		s = getservbyname(n, "tcp");
794 		if (s == NULL)
795 			s = getservbyname(n, "udp");
796 		if (s == NULL)
797 			return (-1);
798 		return (ntohs(s->s_port));
799 	}
800 
801 	return ((unsigned short)llval);
802 }