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 extern TAILQ_HEAD(vhosthead, vhost) hosts;
77 struct vhost {
78 	const char	*domain;
79 	const char	*cert;
80 	const char	*key;
81 	const char	*dir;
82 	const char	*cgi;
83 	const char	*entrypoint;
84 	int		 dirfd;
85 
86 	TAILQ_ENTRY(vhost) vhosts;
87 
88 	/* the first location rule is always '*' and holds the default
89 	 * settings for the vhost, then follows the "real" location
90 	 * rules as specified in the configuration. */
91 	struct lochead	 locations;
92 };
93 
94 struct etm {			/* extension to mime */
95 	const char	*mime;
96 	const char	*ext;
97 };
98 
99 struct mime {
100 	struct etm	*t;
101 	size_t		len;
102 	size_t		cap;
103 };
104 
105 struct conf {
106 	/* from command line */
107 	int		 foreground;
108 	int		 verbose;
109 
110 	/* in the config */
111 	int		 port;
112 	int		 ipv6;
113 	uint32_t	 protos;
114 	struct mime	 mime;
115 	char		*chroot;
116 	char		*user;
117 	int		 prefork;
118 };
119 
120 extern const char *config_path;
121 extern struct conf conf;
122 
123 extern struct imsgbuf logibuf, exibuf, servibuf[PROC_MAX];
124 
125 extern int servpipes[PROC_MAX];
126 
127 struct iri {
128 	char		*schema;
129 	char		*host;
130 	char		*port;
131 	uint16_t	 port_no;
132 	char		*path;
133 	char		*query;
134 	char		*fragment;
135 };
136 
137 struct parser {
138 	char		*iri;
139 	struct iri	*parsed;
140 	const char	*err;
141 };
142 
143 struct client;
144 
145 typedef void (imsg_handlerfn)(struct imsgbuf*, struct imsg*, size_t);
146 
147 typedef void (*statefn)(int, short, void*);
148 
149 /*
150  * DFA: handle_handshake is the initial state, close_conn the final.
151  * Sometimes we have an enter_* function to handle the state switch.
152  *
153  * handle_handshake -> handle_open_conn
154  * handle_handshake -> close_conn		// on err
155  *
156  * handle_open_conn -> handle_cgi_reply		// via open_file/dir/...
157  * handle_open_conn -> handle_dirlist		// ...same
158  * handle_open_conn -> send_file		// ...same
159  * handle_open_conn -> start_reply		// on error
160  *
161  * handle_cgi_reply -> handle_cgi	// after logging the CGI reply
162  * handle_cgi_reply -> start_reply	// on error
163  *
164  * handle_cgi -> close_conn
165  *
166  * handle_dirlist -> send_directory_listing
167  * handle_dirlist -> close_conn			// on error
168  *
169  * send_directory_listing -> close_conn
170  *
171  * send_file -> close_conn
172  */
173 struct client {
174 	int		 id;
175 	struct tls	*ctx;
176 	char		 req[GEMINI_URL_LEN];
177 	struct iri	 iri;
178 	char		 domain[DOMAIN_NAME_LEN];
179 	statefn		 next;
180 	int		 code;
181 	const char	*meta;
182 	int		 fd, pfd;
183 	DIR		*dir;
184 
185 	/* big enough to store STATUS + SPACE + META + CRLF */
186 	char		 sbuf[1029];
187 	ssize_t		 len, off;
188 
189 	struct sockaddr_storage	 addr;
190 	struct vhost	*host;	/* host they're talking to */
191 };
192 
193 struct cgireq {
194 	char		buf[GEMINI_URL_LEN];
195 
196 	size_t		iri_schema_off;
197 	size_t		iri_host_off;
198 	size_t		iri_port_off;
199 	size_t		iri_path_off;
200 	size_t		iri_query_off;
201 	size_t		iri_fragment_off;
202 	int		iri_portno;
203 
204 	char		spath[PATH_MAX+1];
205 	char		relpath[PATH_MAX+1];
206 	char		addr[NI_MAXHOST+1];
207 
208 	/* AFAIK there isn't an upper limit for these two fields. */
209 	char		subject[64+1];
210 	char		issuer[64+1];
211 
212 	char		hash[128+1];
213 	char		version[8];
214 	char		cipher[32];
215 	int		cipher_strength;
216 	time_t		notbefore;
217 	time_t		notafter;
218 
219 	size_t		host_off;
220 };
221 
222 enum {
223 	FILE_EXISTS,
224 	FILE_EXECUTABLE,
225 	FILE_DIRECTORY,
226 	FILE_MISSING,
227 };
228 
229 enum imsg_type {
230 	IMSG_CGI_REQ,
231 	IMSG_CGI_RES,
232 	IMSG_LOG,
233 	IMSG_QUIT,
234 };
235 
236 /* gmid.c */
237 char		*data_dir(void);
238 void		 load_local_cert(const char*, const char*);
239 void		 load_vhosts(void);
240 int		 make_socket(int, int);
241 void		 setup_tls(void);
242 void		 init_config(void);
243 void		 free_config(void);
244 void		 drop_priv(void);
245 
246 /* provided by lex/yacc */
247 extern FILE *yyin;
248 extern int yylineno;
249 extern int yyparse(void);
250 extern int yylex(void);
251 
252 void		 yyerror(const char*, ...);
253 int		 parse_portno(const char*);
254 void		 parse_conf(const char*);
255 
256 /* log.c */
257 void		 fatal(const char*, ...)
258 	__attribute__((format (printf, 1, 2)))
259 	__attribute__((__noreturn__));
260 
261 #define LOG_ATTR_FMT __attribute__((format (printf, 2, 3)))
262 void		 log_err(struct client*, const char*, ...)	LOG_ATTR_FMT;
263 void		 log_warn(struct client*, const char*, ...)	LOG_ATTR_FMT;
264 void		 log_notice(struct client*, const char*, ...)	LOG_ATTR_FMT;
265 void		 log_info(struct client*, const char*, ...)	LOG_ATTR_FMT;
266 void		 log_debug(struct client*, const char*, ...)	LOG_ATTR_FMT;
267 void		 log_request(struct client*, char*, size_t);
268 int		 logger_main(int, struct imsgbuf*);
269 
270 /* mime.c */
271 void		 init_mime(struct mime*);
272 void		 add_mime(struct mime*, const char*, const char*);
273 void		 load_default_mime(struct mime*);
274 const char	*mime(struct vhost*, const char*);
275 
276 /* server.c */
277 const char	*vhost_lang(struct vhost*, const char*);
278 const char	*vhost_default_mime(struct vhost*, const char*);
279 const char	*vhost_index(struct vhost*, const char*);
280 int		 vhost_auto_index(struct vhost*, const char*);
281 int		 vhost_block_return(struct vhost*, const char*, int*, const char**);
282 int		 vhost_strip(struct vhost*, const char*);
283 X509_STORE	*vhost_require_ca(struct vhost*, const char*);
284 int		 vhost_disable_log(struct vhost*, const char*);
285 void		 mark_nonblock(int);
286 void		 loop(struct tls*, int, int, struct imsgbuf*);
287 
288 /* ex.c */
289 int		 send_string(int, const char*);
290 int		 recv_string(int, char**);
291 int		 send_iri(int, struct iri*);
292 int		 recv_iri(int, struct iri*);
293 void		 free_recvd_iri(struct iri*);
294 int		 send_vhost(int, struct vhost*);
295 int		 recv_vhost(int, struct vhost**);
296 int		 send_time(int, time_t);
297 int		 recv_time(int, time_t*);
298 int		 send_fd(int, int);
299 int		 recv_fd(int);
300 int		 executor_main(struct imsgbuf*);
301 
302 /* sandbox.c */
303 void		 sandbox_server_process(void);
304 void		 sandbox_executor_process(void);
305 void		 sandbox_logger_process(void);
306 
307 /* utf8.c */
308 int		 valid_multibyte_utf8(struct parser*);
309 char		*utf8_nth(char*, size_t);
310 
311 /* iri.c */
312 int		 parse_iri(char*, struct iri*, const char**);
313 int		 trim_req_iri(char*, const char **);
314 int		 serialize_iri(struct iri*, char*, size_t);
315 char		*pct_decode_str(char *);
316 
317 /* puny.c */
318 int		 puny_decode(const char*, char*, size_t, const char**);
319 
320 /* utils.c */
321 void		 block_signals(void);
322 void		 unblock_signals(void);
323 int		 starts_with(const char*, const char*);
324 int		 ends_with(const char*, const char*);
325 ssize_t		 filesize(int);
326 char		*absolutify_path(const char*);
327 char		*xstrdup(const char*);
328 void		*xcalloc(size_t, size_t);
329 void		 gen_certificate(const char*, const char*, const char*);
330 X509_STORE	*load_ca(const char*);
331 int		 validate_against_ca(X509_STORE*, const uint8_t*, size_t);
332 void		 dispatch_imsg(struct imsgbuf*, imsg_handlerfn**, size_t);
333 
334 #endif