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 #ifndef GMID_H
18 #define GMID_H
19 
20 #include "config.h"
21 
22 #include <sys/socket.h>
23 #include <sys/types.h>
24 
25 #include <arpa/inet.h>
26 #include <netinet/in.h>
27 
28 #include <dirent.h>
29 #include <limits.h>
30 #include <netdb.h>
31 #include <signal.h>
32 #include <stdio.h>
33 #include <stdlib.h>
34 #include <time.h>
35 #include <tls.h>
36 #include <unistd.h>
37 
38 #include <openssl/x509.h>
39 
40 #define GEMINI_URL_LEN (1024+3)	/* URL max len + \r\n + \0 */
41 
42 #define SUCCESS		20
43 #define TEMP_REDIRECT	30
44 #define TEMP_FAILURE	40
45 #define CGI_ERROR	42
46 #define NOT_FOUND	51
47 #define PROXY_REFUSED	53
48 #define BAD_REQUEST	59
49 #define CLIENT_CERT_REQ	60
50 #define CERT_NOT_AUTH	61
51 
52 #define MAX_USERS	64
53 
54 /* maximum hostname and label length, +1 for the NUL-terminator */
55 #define DOMAIN_NAME_LEN	(253+1)
56 #define LABEL_LEN	(63+1)
57 
58 #define PROC_MAX	16
59 
60 TAILQ_HEAD(lochead, location);
61 struct location {
62 	const char	*match;
63 	const char	*lang;
64 	const char	*default_mime;
65 	const char	*index;
66 	int		 auto_index; /* 0 auto, -1 off, 1 on */
67 	int		 block_code;
68 	const char	*block_fmt;
69 	int		 strip;
70 	X509_STORE	*reqca;
71 	int		 disable_log;
72 
73 	TAILQ_ENTRY(location) locations;
74 };
75 
76 TAILQ_HEAD(envhead, envlist);
77 struct envlist {
78 	char		*name;
79 	char		*value;
80 	TAILQ_ENTRY(envlist) envs;
81 };
82 
83 extern TAILQ_HEAD(vhosthead, vhost) hosts;
84 struct vhost {
85 	const char	*domain;
86 	const char	*cert;
87 	const char	*key;
88 	const char	*dir;
89 	const char	*cgi;
90 	const char	*entrypoint;
91 	int		 dirfd;
92 
93 	TAILQ_ENTRY(vhost) vhosts;
94 
95 	/* the first location rule is always '*' and holds the default
96 	 * settings for the vhost, then follows the "real" location
97 	 * rules as specified in the configuration. */
98 	struct lochead	 locations;
99 
100 	struct envhead	 env;
101 };
102 
103 struct etm {			/* extension to mime */
104 	const char	*mime;
105 	const char	*ext;
106 };
107 
108 struct mime {
109 	struct etm	*t;
110 	size_t		len;
111 	size_t		cap;
112 };
113 
114 struct conf {
115 	/* from command line */
116 	int		 foreground;
117 	int		 verbose;
118 
119 	/* in the config */
120 	int		 port;
121 	int		 ipv6;
122 	uint32_t	 protos;
123 	struct mime	 mime;
124 	char		*chroot;
125 	char		*user;
126 	int		 prefork;
127 };
128 
129 extern const char *config_path;
130 extern struct conf conf;
131 
132 extern struct imsgbuf logibuf, exibuf, servibuf[PROC_MAX];
133 
134 extern int servpipes[PROC_MAX];
135 
136 struct iri {
137 	char		*schema;
138 	char		*host;
139 	char		*port;
140 	uint16_t	 port_no;
141 	char		*path;
142 	char		*query;
143 	char		*fragment;
144 };
145 
146 struct parser {
147 	char		*iri;
148 	struct iri	*parsed;
149 	const char	*err;
150 };
151 
152 struct client;
153 
154 typedef void (imsg_handlerfn)(struct imsgbuf*, struct imsg*, size_t);
155 
156 typedef void (*statefn)(int, short, void*);
157 
158 /*
159  * DFA: handle_handshake is the initial state, close_conn the final.
160  * Sometimes we have an enter_* function to handle the state switch.
161  *
162  * handle_handshake -> handle_open_conn
163  * handle_handshake -> close_conn		// on err
164  *
165  * handle_open_conn -> handle_cgi_reply		// via open_file/dir/...
166  * handle_open_conn -> handle_dirlist		// ...same
167  * handle_open_conn -> send_file		// ...same
168  * handle_open_conn -> start_reply		// on error
169  *
170  * handle_cgi_reply -> handle_cgi	// after logging the CGI reply
171  * handle_cgi_reply -> start_reply	// on error
172  *
173  * handle_cgi -> close_conn
174  *
175  * handle_dirlist -> send_directory_listing
176  * handle_dirlist -> close_conn			// on error
177  *
178  * send_directory_listing -> close_conn
179  *
180  * send_file -> close_conn
181  */
182 struct client {
183 	int		 id;
184 	struct tls	*ctx;
185 	char		 req[GEMINI_URL_LEN];
186 	struct iri	 iri;
187 	char		 domain[DOMAIN_NAME_LEN];
188 	statefn		 next;
189 	int		 code;
190 	const char	*meta;
191 	int		 fd, pfd;
192 	struct dirent	**dir;
193 	int		 dirlen, diroff;
194 
195 	/* big enough to store STATUS + SPACE + META + CRLF */
196 	char		 sbuf[1029];
197 	ssize_t		 len, off;
198 
199 	struct sockaddr_storage	 addr;
200 	struct vhost	*host;	/* host they're talking to */
201 };
202 
203 struct cgireq {
204 	char		buf[GEMINI_URL_LEN];
205 
206 	size_t		iri_schema_off;
207 	size_t		iri_host_off;
208 	size_t		iri_port_off;
209 	size_t		iri_path_off;
210 	size_t		iri_query_off;
211 	size_t		iri_fragment_off;
212 	int		iri_portno;
213 
214 	char		spath[PATH_MAX+1];
215 	char		relpath[PATH_MAX+1];
216 	char		addr[NI_MAXHOST+1];
217 
218 	/* AFAIK there isn't an upper limit for these two fields. */
219 	char		subject[64+1];
220 	char		issuer[64+1];
221 
222 	char		hash[128+1];
223 	char		version[8];
224 	char		cipher[32];
225 	int		cipher_strength;
226 	time_t		notbefore;
227 	time_t		notafter;
228 
229 	size_t		host_off;
230 };
231 
232 enum {
233 	FILE_EXISTS,
234 	FILE_EXECUTABLE,
235 	FILE_DIRECTORY,
236 	FILE_MISSING,
237 };
238 
239 enum imsg_type {
240 	IMSG_CGI_REQ,
241 	IMSG_CGI_RES,
242 	IMSG_LOG,
243 	IMSG_QUIT,
244 };
245 
246 /* gmid.c */
247 char		*data_dir(void);
248 void		 load_local_cert(const char*, const char*);
249 void		 load_vhosts(void);
250 int		 make_socket(int, int);
251 void		 setup_tls(void);
252 void		 init_config(void);
253 void		 free_config(void);
254 void		 drop_priv(void);
255 
256 /* provided by lex/yacc */
257 extern FILE *yyin;
258 extern int yylineno;
259 extern int yyparse(void);
260 extern int yylex(void);
261 
262 void		 yyerror(const char*, ...);
263 int		 parse_portno(const char*);
264 void		 parse_conf(const char*);
265 
266 /* log.c */
267 void		 fatal(const char*, ...)
268 	__attribute__((format (printf, 1, 2)))
269 	__attribute__((__noreturn__));
270 
271 #define LOG_ATTR_FMT __attribute__((format (printf, 2, 3)))
272 void		 log_err(struct client*, const char*, ...)	LOG_ATTR_FMT;
273 void		 log_warn(struct client*, const char*, ...)	LOG_ATTR_FMT;
274 void		 log_notice(struct client*, const char*, ...)	LOG_ATTR_FMT;
275 void		 log_info(struct client*, const char*, ...)	LOG_ATTR_FMT;
276 void		 log_debug(struct client*, const char*, ...)	LOG_ATTR_FMT;
277 void		 log_request(struct client*, char*, size_t);
278 int		 logger_main(int, struct imsgbuf*);
279 
280 /* mime.c */
281 void		 init_mime(struct mime*);
282 void		 add_mime(struct mime*, const char*, const char*);
283 void		 load_default_mime(struct mime*);
284 const char	*mime(struct vhost*, const char*);
285 
286 /* server.c */
287 const char	*vhost_lang(struct vhost*, const char*);
288 const char	*vhost_default_mime(struct vhost*, const char*);
289 const char	*vhost_index(struct vhost*, const char*);
290 int		 vhost_auto_index(struct vhost*, const char*);
291 int		 vhost_block_return(struct vhost*, const char*, int*, const char**);
292 int		 vhost_strip(struct vhost*, const char*);
293 X509_STORE	*vhost_require_ca(struct vhost*, const char*);
294 int		 vhost_disable_log(struct vhost*, const char*);
295 void		 mark_nonblock(int);
296 void		 loop(struct tls*, int, int, struct imsgbuf*);
297 
298 /* dirs.c */
299 int		 scandir_fd(int, struct dirent***, int(*)(const struct dirent*),
300 		    int(*)(const struct dirent**, const struct dirent**));
301 int		 select_non_dot(const struct dirent*);
302 int		 select_non_dotdot(const struct dirent*);
303 
304 /* ex.c */
305 int		 send_string(int, const char*);
306 int		 recv_string(int, char**);
307 int		 send_iri(int, struct iri*);
308 int		 recv_iri(int, struct iri*);
309 void		 free_recvd_iri(struct iri*);
310 int		 send_vhost(int, struct vhost*);
311 int		 recv_vhost(int, struct vhost**);
312 int		 send_time(int, time_t);
313 int		 recv_time(int, time_t*);
314 int		 send_fd(int, int);
315 int		 recv_fd(int);
316 int		 executor_main(struct imsgbuf*);
317 
318 /* sandbox.c */
319 void		 sandbox_server_process(void);
320 void		 sandbox_executor_process(void);
321 void		 sandbox_logger_process(void);
322 
323 /* utf8.c */
324 int		 valid_multibyte_utf8(struct parser*);
325 char		*utf8_nth(char*, size_t);
326 
327 /* iri.c */
328 int		 parse_iri(char*, struct iri*, const char**);
329 int		 trim_req_iri(char*, const char **);
330 int		 serialize_iri(struct iri*, char*, size_t);
331 char		*pct_decode_str(char *);
332 
333 /* puny.c */
334 int		 puny_decode(const char*, char*, size_t, const char**);
335 
336 /* utils.c */
337 void		 block_signals(void);
338 void		 unblock_signals(void);
339 int		 starts_with(const char*, const char*);
340 int		 ends_with(const char*, const char*);
341 ssize_t		 filesize(int);
342 char		*absolutify_path(const char*);
343 char		*xstrdup(const char*);
344 void		*xcalloc(size_t, size_t);
345 void		 gen_certificate(const char*, const char*, const char*);
346 X509_STORE	*load_ca(const char*);
347 int		 validate_against_ca(X509_STORE*, const uint8_t*, size_t);
348 void		 dispatch_imsg(struct imsgbuf*, imsg_handlerfn**, size_t);
349 
350 #endif