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 <inttypes.h>
33 #include <netdb.h>
34 #include <stdio.h>
35 #include <stdlib.h>
36 #include <limits.h>
37 #include <stdarg.h>
38 #include <stdint.h>
39 #include <string.h>
40 #include <unistd.h>
41 #include <ctype.h>
42 #include <errno.h>
43 #include <fcntl.h>
44 #include <pwd.h>
45 #include <imsg.h>
46 
47 #include "log.h"
48 #include "proc.h"
49 
50 #include "galileo.h"
51 
52 TAILQ_HEAD(files, file)		 files = TAILQ_HEAD_INITIALIZER(files);
53 static struct file {
54 	TAILQ_ENTRY(file)	 entry;
55 	FILE			*stream;
56 	char			*name;
57 	size_t			 ungetpos;
58 	size_t			 ungetsize;
59 	u_char			*ungetbuf;
60 	int			 eof_reached;
61 	int			 lineno;
62 	int			 errors;
63 } *file, *topfile;
64 struct file	*pushfile(const char *, int);
65 int		 popfile(void);
66 int		 yyparse(void);
67 int		 yylex(void);
68 int		 yyerror(const char *, ...)
69     __attribute__((__format__ (printf, 1, 2)))
70     __attribute__((__nonnull__ (1)));
71 int		 kw_cmp(const void *, const void *);
72 int		 lookup(char *);
73 int		 igetc(void);
74 int		 lgetc(int);
75 void		 lungetc(int);
76 int		 findeol(void);
77 
78 TAILQ_HEAD(symhead, sym)	 symhead = TAILQ_HEAD_INITIALIZER(symhead);
79 struct sym {
80 	TAILQ_ENTRY(sym)	 entry;
81 	int			 used;
82 	int			 persist;
83 	char			*nam;
84 	char			*val;
85 };
86 int		 symset(const char *, const char *, int);
87 char		*symget(const char *);
88 
89 int		 getservice(const char *);
90 
91 static struct galileo	*conf = NULL;
92 static struct proxy	*pr = NULL;
93 static int		 errors;
94 
95 typedef struct {
96 	union {
97 		int64_t		 number;
98 		char		*string;
99 	} v;
100 	int lineno;
101 } YYSTYPE;
102 
103 %}
104 
105 %token	INCLUDE ERROR
106 %token	CHROOT HOSTNAME NO PORT PREFORK PROXY SOURCE STYLESHEET TLS
107 %token	<v.number>	NUMBER
108 %token	<v.string>	STRING
109 %type	<v.number>	port
110 %type	<v.string>	string
111 
112 %%
113 
114 grammar		: /* empty */
115 		| grammar include '\n'
116 		| grammar '\n'
117 		| grammar varset '\n'
118 		| grammar main '\n'
119 		| grammar proxy '\n'
120 		| grammar error '\n'		{ file->errors++; }
121 		;
122 
123 include		: INCLUDE string {
124 			struct file *nfile;
125 
126 			if ((nfile = pushfile($2, 0)) == NULL) {
127 				yyerror("failed to include file %s", $2);
128 				free($2);
129 				YYERROR;
130 			}
131 			free($2);
132 
133 			file = nfile;
134 			lungetc('\n');
135 		}
136 		;
137 
138 varset		: STRING '=' STRING {
139 			char *s = $1;
140 			while (*s++) {
141 				if (isspace((unsigned char)*s)) {
142 					yyerror("macro name cannot contain "
143 					    "whitespace");
144 					free($1);
145 					free($3);
146 					YYERROR;
147 				}
148 			}
149 			if (symset($1, $3, 0) == -1)
150 				fatalx("cannot store variable");
151 			free($1);
152 			free($3);
153 		}
154 		;
155 
156 main		: PREFORK NUMBER {
157 			if ($2 <= 0 || $2 > PROC_MAX_INSTANCES) {
158 				yyerror("invalid number of preforked "
159 				    "proxies: %"PRId64, $2);
160 				YYERROR;
161 			}
162 			conf->sc_prefork = $2;
163 		}
164 		| CHROOT STRING {
165 			size_t n;
166 
167 			n = strlcpy(conf->sc_chroot, $2,
168 			    sizeof(conf->sc_chroot));
169 			if (n >= sizeof(conf->sc_chroot))
170 				yyerror("chroot path too long!");
171 			free($2);
172 		}
173 		;
174 
175 proxy		: PROXY STRING {
176 			struct proxy	*p;
177 			size_t		 n;
178 
179 			if ((p = calloc(1, sizeof(*p))) == NULL)
180 				fatal("calloc");
181 
182 			n = strlcpy(p->pr_conf.host, $2,
183 			    sizeof(p->pr_conf.host));
184 			if (n >= sizeof(p->pr_conf.host)) {
185 				yyerror("server name too long");
186 				free($2);
187 				free(p);
188 				YYERROR;
189 			}
190 			free($2);
191 
192 			pr = p;
193 		} '{' optnl proxyopts_l '}' {
194 			/* check if duplicate */
195 			if (proxy_match(conf, pr->pr_conf.host) != NULL)
196 				yyerror("duplicate proxy `%s'",
197 				    pr->pr_conf.host);
198 
199 			TAILQ_INSERT_TAIL(&conf->sc_proxies, pr, pr_entry);
200 
201 			if (*pr->pr_conf.proxy_addr == '\0')
202 				yyerror("missing source in proxy block `%s'",
203 				    pr->pr_conf.host);
204 
205 			pr = NULL;
206 		}
207 		;
208 
209 proxyopts_l	: proxyopts_l proxyoptsl nl
210 		| proxyoptsl optnl
211 		;
212 
213 proxyoptsl	: SOURCE STRING proxyport {
214 			size_t n;
215 
216 			n = strlcpy(pr->pr_conf.proxy_addr, $2,
217 			    sizeof(pr->pr_conf.proxy_addr));
218 			if (n >= sizeof(pr->pr_conf.proxy_addr))
219 				yyerror("proxy source too long!");
220 
221 			if (*pr->pr_conf.proxy_name == '\0') {
222 				n = strlcpy(pr->pr_conf.proxy_name, $2,
223 				    sizeof(pr->pr_conf.proxy_name));
224 				if (n >= sizeof(pr->pr_conf.proxy_name))
225 					yyerror("proxy hostname too long!");
226 			}
227 
228 			free($2);
229 		}
230 		| HOSTNAME STRING {
231 			size_t n;
232 
233 			n = strlcpy(pr->pr_conf.proxy_name, $2,
234 			    sizeof(pr->pr_conf.proxy_name));
235 			if (n >= sizeof(pr->pr_conf.proxy_name))
236 				yyerror("proxy hostname too long!");
237 			free($2);
238 		}
239 		| STYLESHEET string {
240 			size_t n;
241 
242 			n = strlcpy(pr->pr_conf.stylesheet, $2,
243 			    sizeof(pr->pr_conf.stylesheet));
244 			if (n >= sizeof(pr->pr_conf.stylesheet))
245 				yyerror("stylesheet path too long!");
246 			free($2);
247 		}
248 		| NO TLS {
249 			pr->pr_conf.no_tls = 1;
250 		}
251 		;
252 
253 proxyport	: /* empty */ {
254 			strlcpy(pr->pr_conf.proxy_port, "1965",
255 			    sizeof(pr->pr_conf.proxy_port));
256 		}
257 		| PORT port {
258 			size_t len;
259 			int n;
260 
261 			len = sizeof(pr->pr_conf.proxy_port);
262 			n = snprintf(pr->pr_conf.proxy_port, len,
263 			    "%"PRId64, $2);
264 			if (n < 0 || (size_t)n >= len)
265 				fatal("port number too long?");
266 		};
267 
268 port		: NUMBER {
269 			if ($1 <= 0 || $1 > (int)USHRT_MAX) {
270 				yyerror("invalid port: %"PRId64, $1);
271 				YYERROR;
272 			}
273 			$$ = $1;
274 		}
275 		| STRING {
276 			int val;
277 
278 			if ((val = getservice($1)) == -1) {
279 				yyerror("invalid port: %s", $1);
280 				free($1);
281 				YYERROR;
282 			}
283 			free($1);
284 			$$ = val;
285 		}
286 		;
287 
288 string		: STRING string {
289 			if (asprintf(&$$, "%s%s", $1, $2) == -1)
290 				fatal("asprintf string");
291 			free($1);
292 			free($2);
293 		}
294 		| STRING
295 		;
296 
297 optnl		: '\n' optnl
298 		|
299 		;
300 
301 nl		: '\n' optnl
302 		;
303 
304 %%
305 
306 struct keywords {
307 	const char	*k_name;
308 	int		 k_val;
309 };
310 
311 int
312 yyerror(const char *fmt, ...)
313 {
314 	va_list	 ap;
315 	char	*msg;
316 
317 	file->errors++;
318 	va_start(ap, fmt);
319 	if (vasprintf(&msg, fmt, ap) == -1)
320 		fatal("yyerror vasprintf");
321 	va_end(ap);
322 	log_warnx("%s:%d: %s", file->name, yylval.lineno, msg);
323 	free(msg);
324 	return (0);
325 }
326 
327 int
328 kw_cmp(const void *k, const void *e)
329 {
330 	return (strcmp(k, ((const struct keywords *)e)->k_name));
331 }
332 
333 int
334 lookup(char *s)
335 {
336 	/* this has to be sorted always */
337 	static const struct keywords keywords[] = {
338 		{ "chroot",	CHROOT },
339 		{ "hostname",	HOSTNAME },
340 		{ "include",	INCLUDE },
341 		{ "no",		NO },
342 		{ "port",	PORT },
343 		{ "prefork",	PREFORK },
344 		{ "proxy",	PROXY },
345 		{ "source",	SOURCE },
346 		{ "stylesheet",	STYLESHEET},
347 		{ "tls",	TLS },
348 	};
349 	const struct keywords	*p;
350 
351 	p = bsearch(s, keywords, nitems(keywords), sizeof(keywords[0]),
352 	    kw_cmp);
353 
354 	if (p)
355 		return (p->k_val);
356 	else
357 		return (STRING);
358 }
359 
360 #define START_EXPAND	1
361 #define DONE_EXPAND	2
362 
363 static int	expanding;
364 
365 int
366 igetc(void)
367 {
368 	int	c;
369 
370 	while (1) {
371 		if (file->ungetpos > 0)
372 			c = file->ungetbuf[--file->ungetpos];
373 		else
374 			c = getc(file->stream);
375 
376 		if (c == START_EXPAND)
377 			expanding = 1;
378 		else if (c == DONE_EXPAND)
379 			expanding = 0;
380 		else
381 			break;
382 	}
383 	return (c);
384 }
385 
386 int
387 lgetc(int quotec)
388 {
389 	int		c, next;
390 
391 	if (quotec) {
392 		if ((c = igetc()) == EOF) {
393 			yyerror("reached end of file while parsing "
394 			    "quoted string");
395 			if (file == topfile || popfile() == EOF)
396 				return (EOF);
397 			return (quotec);
398 		}
399 		return (c);
400 	}
401 
402 	while ((c = igetc()) == '\\') {
403 		next = igetc();
404 		if (next != '\n') {
405 			c = next;
406 			break;
407 		}
408 		yylval.lineno = file->lineno;
409 		file->lineno++;
410 	}
411 	if (c == '\t' || c == ' ') {
412 		/* Compress blanks to a single space. */
413 		do {
414 			c = getc(file->stream);
415 		} while (c == '\t' || c == ' ');
416 		ungetc(c, file->stream);
417 		c = ' ';
418 	}
419 
420 	if (c == EOF) {
421 		/*
422 		 * Fake EOL when hit EOF for the first time. This gets line
423 		 * count right if last line in included file is syntactically
424 		 * invalid and has no newline.
425 		 */
426 		if (file->eof_reached == 0) {
427 			file->eof_reached = 1;
428 			return ('\n');
429 		}
430 		while (c == EOF) {
431 			if (file == topfile || popfile() == EOF)
432 				return (EOF);
433 			c = igetc();
434 		}
435 	}
436 	return (c);
437 }
438 
439 void
440 lungetc(int c)
441 {
442 	if (c == EOF)
443 		return;
444 
445 	if (file->ungetpos >= file->ungetsize) {
446 		void *p = reallocarray(file->ungetbuf, file->ungetsize, 2);
447 		if (p == NULL)
448 			err(1, "%s", __func__);
449 		file->ungetbuf = p;
450 		file->ungetsize *= 2;
451 	}
452 	file->ungetbuf[file->ungetpos++] = c;
453 }
454 
455 int
456 findeol(void)
457 {
458 	int	c;
459 
460 	/* skip to either EOF or the first real EOL */
461 	while (1) {
462 		c = lgetc(0);
463 		if (c == '\n') {
464 			file->lineno++;
465 			break;
466 		}
467 		if (c == EOF)
468 			break;
469 	}
470 	return (ERROR);
471 }
472 
473 int
474 yylex(void)
475 {
476 	char	 buf[8096];
477 	char	*p, *val;
478 	int	 quotec, next, c;
479 	int	 token;
480 
481 top:
482 	p = buf;
483 	while ((c = lgetc(0)) == ' ' || c == '\t')
484 		; /* nothing */
485 
486 	yylval.lineno = file->lineno;
487 	if (c == '#')
488 		while ((c = lgetc(0)) != '\n' && c != EOF)
489 			; /* nothing */
490 	if (c == '$' && !expanding) {
491 		while (1) {
492 			if ((c = lgetc(0)) == EOF)
493 				return (0);
494 
495 			if (p + 1 >= buf + sizeof(buf) - 1) {
496 				yyerror("string too long");
497 				return (findeol());
498 			}
499 			if (isalnum(c) || c == '_') {
500 				*p++ = c;
501 				continue;
502 			}
503 			*p = '\0';
504 			lungetc(c);
505 			break;
506 		}
507 		val = symget(buf);
508 		if (val == NULL) {
509 			yyerror("macro '%s' not defined", buf);
510 			return (findeol());
511 		}
512 		p = val + strlen(val) - 1;
513 		lungetc(DONE_EXPAND);
514 		while (p >= val) {
515 			lungetc((unsigned char)*p);
516 			p--;
517 		}
518 		lungetc(START_EXPAND);
519 		goto top;
520 	}
521 
522 	switch (c) {
523 	case '\'':
524 	case '"':
525 		quotec = c;
526 		while (1) {
527 			if ((c = lgetc(quotec)) == EOF)
528 				return (0);
529 			if (c == '\n') {
530 				file->lineno++;
531 				continue;
532 			} else if (c == '\\') {
533 				if ((next = lgetc(quotec)) == EOF)
534 					return (0);
535 				if (next == quotec || next == ' ' ||
536 				    next == '\t')
537 					c = next;
538 				else if (next == '\n') {
539 					file->lineno++;
540 					continue;
541 				} else
542 					lungetc(next);
543 			} else if (c == quotec) {
544 				*p = '\0';
545 				break;
546 			} else if (c == '\0') {
547 				yyerror("syntax error");
548 				return (findeol());
549 			}
550 			if (p + 1 >= buf + sizeof(buf) - 1) {
551 				yyerror("string too long");
552 				return (findeol());
553 			}
554 			*p++ = c;
555 		}
556 		yylval.v.string = strdup(buf);
557 		if (yylval.v.string == NULL)
558 			fatal("yylex: strdup");
559 		return (STRING);
560 	}
561 
562 #define allowed_to_end_number(x) \
563 	(isspace(x) || x == ')' || x ==',' || x == '/' || x == '}' || x == '=')
564 
565 	if (c == '-' || isdigit(c)) {
566 		do {
567 			*p++ = c;
568 			if ((size_t)(p-buf) >= sizeof(buf)) {
569 				yyerror("string too long");
570 				return (findeol());
571 			}
572 		} while ((c = lgetc(0)) != EOF && isdigit(c));
573 		lungetc(c);
574 		if (p == buf + 1 && buf[0] == '-')
575 			goto nodigits;
576 		if (c == EOF || allowed_to_end_number(c)) {
577 			const char *errstr = NULL;
578 
579 			*p = '\0';
580 			yylval.v.number = strtonum(buf, LLONG_MIN,
581 			    LLONG_MAX, &errstr);
582 			if (errstr) {
583 				yyerror("\"%s\" invalid number: %s",
584 				    buf, errstr);
585 				return (findeol());
586 			}
587 			return (NUMBER);
588 		} else {
589 nodigits:
590 			while (p > buf + 1)
591 				lungetc((unsigned char)*--p);
592 			c = (unsigned char)*--p;
593 			if (c == '-')
594 				return (c);
595 		}
596 	}
597 
598 #define allowed_in_string(x) \
599 	(isalnum(x) || (ispunct(x) && x != '(' && x != ')' && \
600 	x != '{' && x != '}' && \
601 	x != '!' && x != '=' && x != '#' && \
602 	x != ','))
603 
604 	if (isalnum(c) || c == ':' || c == '_' || c == '/') {
605 		do {
606 			*p++ = c;
607 			if ((size_t)(p-buf) >= sizeof(buf)) {
608 				yyerror("string too long");
609 				return (findeol());
610 			}
611 		} while ((c = lgetc(0)) != EOF && (allowed_in_string(c)));
612 		lungetc(c);
613 		*p = '\0';
614 		if ((token = lookup(buf)) == STRING)
615 			if ((yylval.v.string = strdup(buf)) == NULL)
616 				fatal("yylex: strdup");
617 		return (token);
618 	}
619 	if (c == '\n') {
620 		yylval.lineno = file->lineno;
621 		file->lineno++;
622 	}
623 	if (c == EOF)
624 		return (0);
625 	return (c);
626 }
627 
628 struct file *
629 pushfile(const char *name, int secret)
630 {
631 	struct file	*nfile;
632 
633 	if ((nfile = calloc(1, sizeof(struct file))) == NULL) {
634 		log_warn("%s", __func__);
635 		return (NULL);
636 	}
637 	if ((nfile->name = strdup(name)) == NULL) {
638 		log_warn("%s", __func__);
639 		free(nfile);
640 		return (NULL);
641 	}
642 	if ((nfile->stream = fopen(nfile->name, "r")) == NULL) {
643 		free(nfile->name);
644 		free(nfile);
645 		return (NULL);
646 	}
647 	nfile->lineno = TAILQ_EMPTY(&files) ? 1 : 0;
648 	nfile->ungetsize = 16;
649 	nfile->ungetbuf = malloc(nfile->ungetsize);
650 	if (nfile->ungetbuf == NULL) {
651 		log_warn("%s", __func__);
652 		fclose(nfile->stream);
653 		free(nfile->name);
654 		free(nfile);
655 		return (NULL);
656 	}
657 	TAILQ_INSERT_TAIL(&files, nfile, entry);
658 	return (nfile);
659 }
660 
661 int
662 popfile(void)
663 {
664 	struct file	*prev;
665 
666 	if ((prev = TAILQ_PREV(file, files, entry)) != NULL)
667 		prev->errors += file->errors;
668 
669 	TAILQ_REMOVE(&files, file, entry);
670 	fclose(file->stream);
671 	free(file->name);
672 	free(file->ungetbuf);
673 	free(file);
674 	file = prev;
675 	return (file ? 0 : EOF);
676 }
677 
678 int
679 parse_config(const char *filename, struct galileo *env)
680 {
681 	struct sym	*sym, *next;
682 	size_t		 n;
683 
684 	conf = env;
685 
686 	n = strlcpy(conf->sc_conffile, filename, sizeof(conf->sc_conffile));
687 	if (n >= sizeof(conf->sc_conffile)) {
688 		log_warn("path too long: %s", filename);
689 		return (-1);
690 	}
691 
692 	if ((file = pushfile(filename, 0)) == NULL) {
693 		log_warn("failed to open %s", filename);
694 		return (-1);
695 	}
696 	topfile = file;
697 	setservent(1);
698 
699 	yyparse();
700 	if (TAILQ_EMPTY(&conf->sc_proxies))
701 		yyerror("no proxies defined");
702 	errors = file->errors;
703 	popfile();
704 
705 	endservent();
706 
707 	/* Free macros and check which have not been used. */
708 	TAILQ_FOREACH_SAFE(sym, &symhead, entry, next) {
709 		if (!sym->used)
710 			fprintf(stderr, "warning: macro `%s' not used\n",
711 			    sym->nam);
712 		if (!sym->persist) {
713 			free(sym->nam);
714 			free(sym->val);
715 			TAILQ_REMOVE(&symhead, sym, entry);
716 			free(sym);
717 		}
718 	}
719 
720 	if (errors)
721 		return (-1);
722 
723 	return (0);
724 }
725 
726 int
727 symset(const char *nam, const char *val, int persist)
728 {
729 	struct sym	*sym;
730 
731 	TAILQ_FOREACH(sym, &symhead, entry) {
732 		if (strcmp(nam, sym->nam) == 0)
733 			break;
734 	}
735 
736 	if (sym != NULL) {
737 		if (sym->persist == 1)
738 			return (0);
739 		else {
740 			free(sym->nam);
741 			free(sym->val);
742 			TAILQ_REMOVE(&symhead, sym, entry);
743 			free(sym);
744 		}
745 	}
746 	if ((sym = calloc(1, sizeof(*sym))) == NULL)
747 		return (-1);
748 
749 	sym->nam = strdup(nam);
750 	if (sym->nam == NULL) {
751 		free(sym);
752 		return (-1);
753 	}
754 	sym->val = strdup(val);
755 	if (sym->val == NULL) {
756 		free(sym->nam);
757 		free(sym);
758 		return (-1);
759 	}
760 	sym->used = 0;
761 	sym->persist = persist;
762 	TAILQ_INSERT_TAIL(&symhead, sym, entry);
763 	return (0);
764 }
765 
766 int
767 cmdline_symset(char *s)
768 {
769 	char	*sym, *val;
770 	int	ret;
771 
772 	if ((val = strrchr(s, '=')) == NULL)
773 		return (-1);
774 	sym = strndup(s, val - s);
775 	if (sym == NULL)
776 		fatal("%s: strndup", __func__);
777 	ret = symset(sym, val + 1, 1);
778 	free(sym);
779 
780 	return (ret);
781 }
782 
783 char *
784 symget(const char *nam)
785 {
786 	struct sym	*sym;
787 
788 	TAILQ_FOREACH(sym, &symhead, entry) {
789 		if (strcmp(nam, sym->nam) == 0) {
790 			sym->used = 1;
791 			return (sym->val);
792 		}
793 	}
794 	return (NULL);
795 }
796 
797 int
798 getservice(const char *n)
799 {
800 	struct servent	*s;
801 	const char	*errstr;
802 	long long	 llval;
803 
804 	llval = strtonum(n, 0, UINT16_MAX, &errstr);
805 	if (errstr) {
806 		s = getservbyname(n, "tcp");
807 		if (s == NULL)
808 			s = getservbyname(n, "udp");
809 		if (s == NULL)
810 			return (-1);
811 		return (ntohs(s->s_port));
812 	}
813 
814 	return ((unsigned short)llval);
815 }