1 /*
2  * Copyright (c) 2020 Omar Polo <op@omarpolo.com>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include <err.h>
18 #include <errno.h>
19 
20 #include <fcntl.h>
21 #include <limits.h>
22 #include <netdb.h>
23 #include <signal.h>
24 #include <stdarg.h>
25 #include <string.h>
26 
27 #include "gmid.h"
28 
29 struct vhost hosts[HOSTSLEN];
30 
31 int goterror;
32 
33 int exfd;
34 
35 struct conf conf;
36 
37 struct etm {			/* file extension to mime */
38 	const char	*mime;
39 	const char	*ext;
40 } filetypes[] = {
41 	{"application/pdf",	"pdf"},
42 
43 	{"image/gif",		"gif"},
44 	{"image/jpeg",		"jpg"},
45 	{"image/jpeg",		"jpeg"},
46 	{"image/png",		"png"},
47 	{"image/svg+xml",	"svg"},
48 
49 	{"text/gemini",		"gemini"},
50 	{"text/gemini",		"gmi"},
51 	{"text/markdown",	"markdown"},
52 	{"text/markdown",	"md"},
53 	{"text/plain",		"txt"},
54 	{"text/xml",		"xml"},
55 
56 	{NULL, NULL}
57 };
58 
59 void
60 fatal(const char *fmt, ...)
61 {
62 	va_list ap;
63 
64 	va_start(ap, fmt);
65 
66 	if (conf.foreground) {
67 		vfprintf(stderr, fmt, ap);
68 		fprintf(stderr, "\n");
69 	} else
70 		vsyslog(LOG_DAEMON | LOG_CRIT, fmt, ap);
71 
72 	va_end(ap);
73 	exit(1);
74 }
75 
76 void
77 logs(int priority, struct client *c,
78     const char *fmt, ...)
79 {
80 	char hbuf[NI_MAXHOST], sbuf[NI_MAXSERV];
81 	char *fmted, *s;
82 	size_t len;
83 	int ec;
84 	va_list ap;
85 
86 	va_start(ap, fmt);
87 
88 	if (c == NULL) {
89 		strncpy(hbuf, "<internal>", sizeof(hbuf));
90 		sbuf[0] = '\0';
91 	} else {
92 		len = sizeof(c->addr);
93 		ec = getnameinfo((struct sockaddr*)&c->addr, len,
94 		    hbuf, sizeof(hbuf),
95 		    sbuf, sizeof(sbuf),
96 		    NI_NUMERICHOST | NI_NUMERICSERV);
97 		if (ec != 0)
98 			fatal("getnameinfo: %s", gai_strerror(ec));
99 	}
100 
101 	if (vasprintf(&fmted, fmt, ap) == -1)
102 		fatal("vasprintf: %s", strerror(errno));
103 
104 	if (conf.foreground)
105 		fprintf(stderr, "%s:%s %s\n", hbuf, sbuf, fmted);
106 	else {
107 		if (asprintf(&s, "%s:%s %s", hbuf, sbuf, fmted) == -1)
108 			fatal("asprintf: %s", strerror(errno));
109 		syslog(priority | LOG_DAEMON, "%s", s);
110 		free(s);
111 	}
112 
113 	free(fmted);
114 
115 	va_end(ap);
116 }
117 
118 void
119 sig_handler(int sig)
120 {
121 	(void)sig;
122 }
123 
124 int
125 starts_with(const char *str, const char *prefix)
126 {
127 	size_t i;
128 
129 	for (i = 0; prefix[i] != '\0'; ++i)
130 		if (str[i] != prefix[i])
131 			return 0;
132 	return 1;
133 }
134 
135 ssize_t
136 filesize(int fd)
137 {
138 	ssize_t len;
139 
140 	if ((len = lseek(fd, 0, SEEK_END)) == -1)
141 		return -1;
142 	if (lseek(fd, 0, SEEK_SET) == -1)
143 		return -1;
144 	return len;
145 }
146 
147 const char *
148 path_ext(const char *path)
149 {
150 	const char *end;
151 
152 	end = path + strlen(path)-1;
153 	for (; end != path; --end) {
154 		if (*end == '.')
155 			return end+1;
156 		if (*end == '/')
157 			break;
158 	}
159 
160 	return NULL;
161 }
162 
163 const char *
164 mime(const char *path)
165 {
166 	const char *ext, *def = "application/octet-stream";
167 	struct etm *t;
168 
169 	if ((ext = path_ext(path)) == NULL)
170 		return def;
171 
172 	for (t = filetypes; t->mime != NULL; ++t)
173 		if (!strcmp(ext, t->ext))
174 			return t->mime;
175 
176 	return def;
177 }
178 
179 char *
180 absolutify_path(const char *path)
181 {
182 	char *wd, *r;
183 
184 	if (*path == '/')
185 		return strdup(path);
186 
187 	wd = getcwd(NULL, 0);
188 	if (asprintf(&r, "%s/%s", wd, path) == -1)
189 		err(1, "asprintf");
190 	free(wd);
191 	return r;
192 }
193 
194 void
195 yyerror(const char *msg)
196 {
197 	goterror = 1;
198 	fprintf(stderr, "%d: %s\n", yylineno, msg);
199 }
200 
201 int
202 parse_portno(const char *p)
203 {
204 	char *ep;
205 	long lval;
206 
207 	errno = 0;
208 	lval = strtol(p, &ep, 10);
209 	if (p[0] == '\0' || *ep != '\0')
210 		errx(1, "not a number: %s", p);
211 	if (lval < 0 || lval > UINT16_MAX)
212 		errx(1, "port number out of range for domain %s: %ld", p, lval);
213 	return lval;
214 }
215 
216 void
217 parse_conf(const char *path)
218 {
219 	if ((yyin = fopen(path, "r")) == NULL)
220 		err(1, "cannot open config %s", path);
221 	yyparse();
222 	fclose(yyin);
223 
224 	if (goterror)
225 		exit(1);
226 }
227 
228 void
229 load_vhosts(struct tls_config *tlsconf)
230 {
231 	struct vhost *h;
232 
233 	/* we need to set something, then we can add how many key we want */
234 	if (tls_config_set_keypair_file(tlsconf, hosts->cert, hosts->key))
235 		errx(1, "tls_config_set_keypair_file failed");
236 
237 	for (h = hosts; h->domain != NULL; ++h) {
238 		if (tls_config_add_keypair_file(tlsconf, h->cert, h->key) == -1)
239 			errx(1, "failed to load the keypair (%s, %s)",
240 			    h->cert, h->key);
241 
242 		if ((h->dirfd = open(h->dir, O_RDONLY | O_DIRECTORY)) == -1)
243 			err(1, "open %s for domain %s", h->dir, h->domain);
244 	}
245 }
246 
247 int
248 make_socket(int port, int family)
249 {
250 	int sock, v;
251 	struct sockaddr_in addr4;
252 	struct sockaddr_in6 addr6;
253 	struct sockaddr *addr;
254 	socklen_t len;
255 
256         switch (family) {
257 	case AF_INET:
258 		bzero(&addr4, sizeof(addr4));
259 		addr4.sin_family = family;
260 		addr4.sin_port = htons(port);
261 		addr4.sin_addr.s_addr = INADDR_ANY;
262 		addr = (struct sockaddr*)&addr4;
263 		len = sizeof(addr4);
264 		break;
265 
266 	case AF_INET6:
267 		bzero(&addr6, sizeof(addr6));
268 		addr6.sin6_family = AF_INET6;
269 		addr6.sin6_port = htons(port);
270 		addr6.sin6_addr = in6addr_any;
271 		addr = (struct sockaddr*)&addr6;
272 		len = sizeof(addr6);
273 		break;
274 
275 	default:
276 		/* unreachable */
277 		abort();
278 	}
279 
280 	if ((sock = socket(family, SOCK_STREAM, 0)) == -1)
281 		fatal("socket: %s", strerror(errno));
282 
283 	v = 1;
284 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &v, sizeof(v)) == -1)
285 		fatal("setsockopt(SO_REUSEADDR): %s", strerror(errno));
286 
287 	v = 1;
288 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEPORT, &v, sizeof(v)) == -1)
289 		fatal("setsockopt(SO_REUSEPORT): %s", strerror(errno));
290 
291 	mark_nonblock(sock);
292 
293 	if (bind(sock, addr, len) == -1)
294 		fatal("bind: %s", strerror(errno));
295 
296 	if (listen(sock, 16) == -1)
297 		fatal("listen: %s", strerror(errno));
298 
299 	return sock;
300 }
301 
302 int
303 listener_main()
304 {
305 	int sock4, sock6;
306 	struct tls *ctx = NULL;
307 	struct tls_config *tlsconf;
308 
309 	if ((tlsconf = tls_config_new()) == NULL)
310 		err(1, "tls_config_new");
311 
312 	/* optionally accept client certs, but don't try to verify them */
313 	tls_config_verify_client_optional(tlsconf);
314 	tls_config_insecure_noverifycert(tlsconf);
315 
316 	if (tls_config_set_protocols(tlsconf, conf.protos) == -1)
317 		err(1, "tls_config_set_protocols");
318 
319 	if ((ctx = tls_server()) == NULL)
320 		errx(1, "tls_server failure");
321 
322 	load_vhosts(tlsconf);
323 
324 	if (tls_configure(ctx, tlsconf) == -1)
325 		errx(1, "tls_configure: %s", tls_error(ctx));
326 
327 	if (!conf.foreground && daemon(0, 1) == -1)
328 		exit(1);
329 
330 	sock4 = make_socket(conf.port, AF_INET);
331 	sock6 = -1;
332 	if (conf.ipv6)
333 		sock6 = make_socket(conf.port, AF_INET6);
334 
335 	sandbox();
336 	loop(ctx, sock4, sock6);
337 
338 	return 0;
339 }
340 
341 void
342 usage(const char *me)
343 {
344 	fprintf(stderr,
345 	    "USAGE: %s [-n] [-c config] | [-6fh] [-C cert] [-d root] [-K key] "
346 	    "[-p port] [-x cgi-bin]\n",
347 	    me);
348 }
349 
350 int
351 main(int argc, char **argv)
352 {
353 	int ch, p[2];
354 	const char *config_path = NULL;
355 	size_t i;
356 	int conftest = 0;
357 
358 	bzero(hosts, sizeof(hosts));
359 	for (i = 0; i < HOSTSLEN; ++i)
360 		hosts[i].dirfd = -1;
361 
362 	conf.foreground = 1;
363 	conf.port = 1965;
364 	conf.ipv6 = 0;
365 	conf.protos = TLS_PROTOCOL_TLSv1_2 | TLS_PROTOCOL_TLSv1_3;
366 
367 	while ((ch = getopt(argc, argv, "6C:c:d:fhK:np:x:")) != -1) {
368 		switch (ch) {
369 		case '6':
370 			conf.ipv6 = 1;
371 			break;
372 
373 		case 'C':
374 			hosts[0].cert = optarg;
375 			break;
376 
377 		case 'c':
378 			config_path = optarg;
379 			break;
380 
381 		case 'd':
382 			free((char*)hosts[0].dir);
383 			if ((hosts[0].dir = absolutify_path(optarg)) == NULL)
384 				err(1, "absolutify_path");
385 			break;
386 
387 		case 'f':
388 			conf.foreground = 1;
389 			break;
390 
391 		case 'h':
392 			usage(*argv);
393 			return 0;
394 
395 		case 'K':
396 			hosts[0].key = optarg;
397 			break;
398 
399 		case 'n':
400 			conftest = 1;
401 			break;
402 
403 		case 'p':
404 			conf.port = parse_portno(optarg);
405 			break;
406 
407 		case 'x':
408 			/* drop the starting / (if any) */
409 			if (*optarg == '/')
410 				optarg++;
411 			hosts[0].cgi = optarg;
412 			break;
413 
414 		default:
415 			usage(*argv);
416 			return 1;
417 		}
418 	}
419 
420 	if (config_path != NULL) {
421 		if (hosts[0].cert != NULL || hosts[0].key != NULL ||
422 		    hosts[0].dir != NULL)
423 			errx(1, "can't specify options in conf mode");
424 		parse_conf(config_path);
425 	} else {
426 		if (hosts[0].cert == NULL || hosts[0].key == NULL ||
427 		    hosts[0].dir == NULL)
428 			errx(1, "missing cert, key or root directory to serve");
429 		hosts[0].domain = "*";
430 	}
431 
432 	if (conftest)
433                 errx(0, "config OK");
434 
435 	signal(SIGPIPE, SIG_IGN);
436 	signal(SIGCHLD, SIG_IGN);
437 
438 #ifdef SIGINFO
439 	signal(SIGINFO, sig_handler);
440 #endif
441 	signal(SIGUSR2, sig_handler);
442 
443 	if (!conf.foreground) {
444 		signal(SIGHUP, SIG_IGN);
445 		if (daemon(1, 1) == -1)
446 			err(1, "daemon");
447 	}
448 
449 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, p) == -1)
450 		fatal("socketpair: %s", strerror(errno));
451 
452 	switch (fork()) {
453 	case -1:
454 		fatal("fork: %s", strerror(errno));
455 
456 	case 0:			/* child */
457 		close(p[0]);
458 		exfd = p[1];
459 		listener_main();
460 		_exit(0);
461 
462 	default:		/* parent */
463 		close(p[1]);
464 		return executor_main(p[0]);
465 	}
466 }