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 <errno.h>
18 #include <fcntl.h>
19 #include <limits.h>
20 #include <netdb.h>
21 #include <signal.h>
22 #include <stdarg.h>
23 #include <string.h>
24 
25 #include "gmid.h"
26 
27 struct vhost hosts[HOSTSLEN];
28 
29 int goterror;
30 
31 int exfd;
32 
33 struct conf conf;
34 
35 struct etm {			/* file extension to mime */
36 	const char	*mime;
37 	const char	*ext;
38 } filetypes[] = {
39 	{"application/pdf",	"pdf"},
40 
41 	{"image/gif",		"gif"},
42 	{"image/jpeg",		"jpg"},
43 	{"image/jpeg",		"jpeg"},
44 	{"image/png",		"png"},
45 	{"image/svg+xml",	"svg"},
46 
47 	{"text/gemini",		"gemini"},
48 	{"text/gemini",		"gmi"},
49 	{"text/markdown",	"markdown"},
50 	{"text/markdown",	"md"},
51 	{"text/plain",		"txt"},
52 	{"text/xml",		"xml"},
53 
54 	{NULL, NULL}
55 };
56 
57 void
58 fatal(const char *fmt, ...)
59 {
60 	va_list ap;
61 
62 	va_start(ap, fmt);
63 
64 	if (conf.foreground) {
65 		vfprintf(stderr, fmt, ap);
66 		fprintf(stderr, "\n");
67 	} else
68 		vsyslog(LOG_DAEMON | LOG_CRIT, fmt, ap);
69 
70 	va_end(ap);
71 	exit(1);
72 }
73 
74 void
75 logs(int priority, struct client *c,
76     const char *fmt, ...)
77 {
78 	char hbuf[NI_MAXHOST], sbuf[NI_MAXSERV];
79 	char *fmted, *s;
80 	size_t len;
81 	int ec;
82 	va_list ap;
83 
84 	va_start(ap, fmt);
85 
86 	if (c == NULL) {
87 		strncpy(hbuf, "<internal>", sizeof(hbuf));
88 		sbuf[0] = '\0';
89 	} else {
90 		len = sizeof(c->addr);
91 		ec = getnameinfo((struct sockaddr*)&c->addr, len,
92 		    hbuf, sizeof(hbuf),
93 		    sbuf, sizeof(sbuf),
94 		    NI_NUMERICHOST | NI_NUMERICSERV);
95 		if (ec != 0)
96 			fatal("getnameinfo: %s", gai_strerror(ec));
97 	}
98 
99 	if (vasprintf(&fmted, fmt, ap) == -1)
100 		fatal("vasprintf: %s", strerror(errno));
101 
102 	if (conf.foreground)
103 		fprintf(stderr, "%s:%s %s\n", hbuf, sbuf, fmted);
104 	else {
105 		if (asprintf(&s, "%s:%s %s", hbuf, sbuf, fmted) == -1)
106 			fatal("asprintf: %s", strerror(errno));
107 		syslog(priority | LOG_DAEMON, "%s", s);
108 		free(s);
109 	}
110 
111 	free(fmted);
112 
113 	va_end(ap);
114 }
115 
116 void
117 sig_handler(int sig)
118 {
119 	(void)sig;
120 }
121 
122 int
123 starts_with(const char *str, const char *prefix)
124 {
125 	size_t i;
126 
127 	for (i = 0; prefix[i] != '\0'; ++i)
128 		if (str[i] != prefix[i])
129 			return 0;
130 	return 1;
131 }
132 
133 ssize_t
134 filesize(int fd)
135 {
136 	ssize_t len;
137 
138 	if ((len = lseek(fd, 0, SEEK_END)) == -1)
139 		return -1;
140 	if (lseek(fd, 0, SEEK_SET) == -1)
141 		return -1;
142 	return len;
143 }
144 
145 const char *
146 path_ext(const char *path)
147 {
148 	const char *end;
149 
150 	end = path + strlen(path)-1;
151 	for (; end != path; --end) {
152 		if (*end == '.')
153 			return end+1;
154 		if (*end == '/')
155 			break;
156 	}
157 
158 	return NULL;
159 }
160 
161 const char *
162 mime(const char *path)
163 {
164 	const char *ext, *def = "application/octet-stream";
165 	struct etm *t;
166 
167 	if ((ext = path_ext(path)) == NULL)
168 		return def;
169 
170 	for (t = filetypes; t->mime != NULL; ++t)
171 		if (!strcmp(ext, t->ext))
172 			return t->mime;
173 
174 	return def;
175 }
176 
177 char *
178 absolutify_path(const char *path)
179 {
180 	char *wd, *r;
181 
182 	if (*path == '/')
183 		return strdup(path);
184 
185 	wd = getcwd(NULL, 0);
186 	if (asprintf(&r, "%s/%s", wd, path) == -1)
187 		fatal("asprintf: %s", strerror(errno));
188 	free(wd);
189 	return r;
190 }
191 
192 void
193 yyerror(const char *msg)
194 {
195 	goterror = 1;
196 	fprintf(stderr, "%d: %s\n", yylineno, msg);
197 }
198 
199 int
200 parse_portno(const char *p)
201 {
202 	char *ep;
203 	long lval;
204 
205 	errno = 0;
206 	lval = strtol(p, &ep, 10);
207 	if (p[0] == '\0' || *ep != '\0')
208 		fatal("not a number: %s", p);
209 	if (lval < 0 || lval > UINT16_MAX)
210 		fatal("port number out of range for domain %s: %ld", p, lval);
211 	return lval;
212 }
213 
214 void
215 parse_conf(const char *path)
216 {
217 	if ((yyin = fopen(path, "r")) == NULL)
218 		fatal("cannot open config %s", path);
219 	yyparse();
220 	fclose(yyin);
221 
222 	if (goterror)
223 		exit(1);
224 }
225 
226 void
227 load_vhosts(struct tls_config *tlsconf)
228 {
229 	struct vhost *h;
230 
231 	/* we need to set something, then we can add how many key we want */
232 	if (tls_config_set_keypair_file(tlsconf, hosts->cert, hosts->key))
233 		fatal("tls_config_set_keypair_file failed");
234 
235 	for (h = hosts; h->domain != NULL; ++h) {
236 		if (tls_config_add_keypair_file(tlsconf, h->cert, h->key) == -1)
237 			fatal("failed to load the keypair (%s, %s)",
238 			    h->cert, h->key);
239 
240 		if ((h->dirfd = open(h->dir, O_RDONLY | O_DIRECTORY)) == -1)
241 			fatal("open %s for domain %s", h->dir, h->domain);
242 	}
243 }
244 
245 int
246 make_socket(int port, int family)
247 {
248 	int sock, v;
249 	struct sockaddr_in addr4;
250 	struct sockaddr_in6 addr6;
251 	struct sockaddr *addr;
252 	socklen_t len;
253 
254         switch (family) {
255 	case AF_INET:
256 		bzero(&addr4, sizeof(addr4));
257 		addr4.sin_family = family;
258 		addr4.sin_port = htons(port);
259 		addr4.sin_addr.s_addr = INADDR_ANY;
260 		addr = (struct sockaddr*)&addr4;
261 		len = sizeof(addr4);
262 		break;
263 
264 	case AF_INET6:
265 		bzero(&addr6, sizeof(addr6));
266 		addr6.sin6_family = AF_INET6;
267 		addr6.sin6_port = htons(port);
268 		addr6.sin6_addr = in6addr_any;
269 		addr = (struct sockaddr*)&addr6;
270 		len = sizeof(addr6);
271 		break;
272 
273 	default:
274 		/* unreachable */
275 		abort();
276 	}
277 
278 	if ((sock = socket(family, SOCK_STREAM, 0)) == -1)
279 		fatal("socket: %s", strerror(errno));
280 
281 	v = 1;
282 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &v, sizeof(v)) == -1)
283 		fatal("setsockopt(SO_REUSEADDR): %s", strerror(errno));
284 
285 	v = 1;
286 	if (setsockopt(sock, SOL_SOCKET, SO_REUSEPORT, &v, sizeof(v)) == -1)
287 		fatal("setsockopt(SO_REUSEPORT): %s", strerror(errno));
288 
289 	mark_nonblock(sock);
290 
291 	if (bind(sock, addr, len) == -1)
292 		fatal("bind: %s", strerror(errno));
293 
294 	if (listen(sock, 16) == -1)
295 		fatal("listen: %s", strerror(errno));
296 
297 	return sock;
298 }
299 
300 int
301 listener_main()
302 {
303 	int sock4, sock6;
304 	struct tls *ctx = NULL;
305 	struct tls_config *tlsconf;
306 
307 	if ((tlsconf = tls_config_new()) == NULL)
308 		fatal("tls_config_new");
309 
310 	/* optionally accept client certs, but don't try to verify them */
311 	tls_config_verify_client_optional(tlsconf);
312 	tls_config_insecure_noverifycert(tlsconf);
313 
314 	if (tls_config_set_protocols(tlsconf, conf.protos) == -1)
315 		fatal("tls_config_set_protocols");
316 
317 	if ((ctx = tls_server()) == NULL)
318 		fatal("tls_server failure");
319 
320 	load_vhosts(tlsconf);
321 
322 	if (tls_configure(ctx, tlsconf) == -1)
323 		fatal("tls_configure: %s", tls_error(ctx));
324 
325 	if (!conf.foreground && daemon(0, 1) == -1)
326 		exit(1);
327 
328 	sock4 = make_socket(conf.port, AF_INET);
329 	sock6 = -1;
330 	if (conf.ipv6)
331 		sock6 = make_socket(conf.port, AF_INET6);
332 
333 	sandbox();
334 	loop(ctx, sock4, sock6);
335 
336 	return 0;
337 }
338 
339 void
340 usage(const char *me)
341 {
342 	fprintf(stderr,
343 	    "USAGE: %s [-n] [-c config] | [-6fh] [-C cert] [-d root] [-K key] "
344 	    "[-p port] [-x cgi-bin]\n",
345 	    me);
346 }
347 
348 int
349 main(int argc, char **argv)
350 {
351 	int ch, p[2];
352 	const char *config_path = NULL;
353 	size_t i;
354 	int conftest = 0;
355 
356 	bzero(hosts, sizeof(hosts));
357 	for (i = 0; i < HOSTSLEN; ++i)
358 		hosts[i].dirfd = -1;
359 
360 	conf.foreground = 1;
361 	conf.port = 1965;
362 	conf.ipv6 = 0;
363 	conf.protos = TLS_PROTOCOL_TLSv1_2 | TLS_PROTOCOL_TLSv1_3;
364 
365 	while ((ch = getopt(argc, argv, "6C:c:d:fhK:np:x:")) != -1) {
366 		switch (ch) {
367 		case '6':
368 			conf.ipv6 = 1;
369 			break;
370 
371 		case 'C':
372 			hosts[0].cert = optarg;
373 			break;
374 
375 		case 'c':
376 			config_path = optarg;
377 			break;
378 
379 		case 'd':
380 			free((char*)hosts[0].dir);
381 			if ((hosts[0].dir = absolutify_path(optarg)) == NULL)
382 				fatal("absolutify_path");
383 			break;
384 
385 		case 'f':
386 			conf.foreground = 1;
387 			break;
388 
389 		case 'h':
390 			usage(*argv);
391 			return 0;
392 
393 		case 'K':
394 			hosts[0].key = optarg;
395 			break;
396 
397 		case 'n':
398 			conftest = 1;
399 			break;
400 
401 		case 'p':
402 			conf.port = parse_portno(optarg);
403 			break;
404 
405 		case 'x':
406 			/* drop the starting / (if any) */
407 			if (*optarg == '/')
408 				optarg++;
409 			hosts[0].cgi = optarg;
410 			break;
411 
412 		default:
413 			usage(*argv);
414 			return 1;
415 		}
416 	}
417 
418 	if (config_path != NULL) {
419 		if (hosts[0].cert != NULL || hosts[0].key != NULL ||
420 		    hosts[0].dir != NULL)
421 			fatal("can't specify options in conf mode");
422 		parse_conf(config_path);
423 	} else {
424 		if (hosts[0].cert == NULL || hosts[0].key == NULL ||
425 		    hosts[0].dir == NULL)
426 			fatal("missing cert, key or root directory to serve");
427 		hosts[0].domain = "*";
428 	}
429 
430 	if (conftest) {
431 		puts("config OK");
432 		return 0;
433 	}
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 			fatal("daemon: %s", strerror(errno));
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 }