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 <signal.h>
30 #include <stdio.h>
31 #include <stdlib.h>
32 #include <time.h>
33 #include <tls.h>
34 #include <unistd.h>
35 
36 #include <openssl/x509.h>
37 
38 #define GEMINI_URL_LEN (1024+3)	/* URL max len + \r\n + \0 */
39 
40 #define SUCCESS		20
41 #define TEMP_REDIRECT	30
42 #define TEMP_FAILURE	40
43 #define CGI_ERROR	42
44 #define NOT_FOUND	51
45 #define PROXY_REFUSED	53
46 #define BAD_REQUEST	59
47 #define CLIENT_CERT_REQ	60
48 #define CERT_NOT_AUTH	61
49 
50 #define MAX_USERS	64
51 
52 #define HOSTSLEN	64
53 #define LOCLEN		32
54 
55 /* maximum hostname and label length, +1 for the NUL-terminator */
56 #define DOMAIN_NAME_LEN	(253+1)
57 #define LABEL_LEN	(63+1)
58 
59 struct location {
60 	const char	*match;
61 	const char	*lang;
62 	const char	*default_mime;
63 	const char	*index;
64 	int		 auto_index; /* 0 auto, -1 off, 1 on */
65 	int		 block_code;
66 	const char	*block_fmt;
67 	int		 strip;
68 	X509_STORE	*reqca;
69 };
70 
71 struct vhost {
72 	const char	*domain;
73 	const char	*cert;
74 	const char	*key;
75 	const char	*dir;
76 	const char	*cgi;
77 	const char	*entrypoint;
78 	int		 dirfd;
79 
80 	/* the first location rule is always '*' and holds the default
81 	 * settings for the vhost, from locations[1] onwards there are
82 	 * the "real" location rules specified in the configuration. */
83 	struct location	 locations[LOCLEN];
84 };
85 
86 extern struct vhost hosts[HOSTSLEN];
87 
88 struct etm {			/* extension to mime */
89 	const char	*mime;
90 	const char	*ext;
91 };
92 
93 struct mime {
94 	struct etm	*t;
95 	size_t		len;
96 	size_t		cap;
97 };
98 
99 struct conf {
100 	/* from command line */
101 	int		 foreground;
102 	int		 verbose;
103 
104 	/* in the config */
105 	int		 port;
106 	int		 ipv6;
107 	uint32_t	 protos;
108 	struct mime	 mime;
109 	char		*chroot;
110 	char		*user;
111 	int		 prefork;
112 };
113 
114 extern const char *config_path;
115 extern struct conf conf;
116 extern int exfd;
117 
118 extern volatile sig_atomic_t hupped;
119 
120 struct iri {
121 	char		*schema;
122 	char		*host;
123 	char		*port;
124 	uint16_t	 port_no;
125 	char		*path;
126 	char		*query;
127 	char		*fragment;
128 };
129 
130 struct parser {
131 	char		*iri;
132 	struct iri	*parsed;
133 	const char	*err;
134 };
135 
136 struct client;
137 
138 typedef void (*statefn)(int, short, void*);
139 
140 /*
141  * DFA: handle_handshake is the initial state, close_conn the final.
142  * Sometimes we have an enter_* function to handle the state switch.
143  *
144  * handle_handshake -> handle_open_conn
145  * handle_handshake -> close_conn		// on err
146  *
147  * handle_open_conn -> handle_cgi_reply		// via open_file/dir/...
148  * handle_open_conn -> handle_dirlist		// ...same
149  * handle_open_conn -> send_file		// ...same
150  * handle_open_conn -> start_reply		// on error
151  *
152  * handle_cgi_reply -> handle_cgi	// after logging the CGI reply
153  * handle_cgi_reply -> start_reply	// on error
154  *
155  * handle_cgi -> close_conn
156  *
157  * handle_dirlist -> send_directory_listing
158  * handle_dirlist -> close_conn			// on error
159  *
160  * send_directory_listing -> close_conn
161  *
162  * send_file -> close_conn
163  */
164 struct client {
165 	struct tls	*ctx;
166 	char		 req[GEMINI_URL_LEN];
167 	struct iri	 iri;
168 	char		 domain[DOMAIN_NAME_LEN];
169 	statefn		 next;
170 	int		 code;
171 	const char	*meta;
172 	int		 fd, pfd;
173 	DIR		*dir;
174 	char		 sbuf[1024];
175 	ssize_t		 len, off;
176 	struct sockaddr_storage	 addr;
177 	struct vhost	*host;	/* host she's talking to */
178 };
179 
180 enum {
181 	FILE_EXISTS,
182 	FILE_EXECUTABLE,
183 	FILE_DIRECTORY,
184 	FILE_MISSING,
185 };
186 
187 /* gmid.c */
188 void		 sig_handler(int);
189 void		 mkdirs(const char*);
190 char		*data_dir(void);
191 void		 load_local_cert(const char*, const char*);
192 void		 load_vhosts(void);
193 int		 make_socket(int, int);
194 void		 setup_tls(void);
195 void		 init_config(void);
196 void		 free_config(void);
197 void		 drop_priv(void);
198 
199 /* provided by lex/yacc */
200 extern FILE *yyin;
201 extern int yylineno;
202 extern int yyparse(void);
203 extern int yylex(void);
204 
205 void		 yyerror(const char*, ...);
206 int		 parse_portno(const char*);
207 void		 parse_conf(const char*);
208 
209 /* log.c */
210 void		 fatal(const char*, ...)
211 	__attribute__((format (printf, 1, 2)))
212 	__attribute__((__noreturn__));
213 
214 #define LOG_ATTR_FMT __attribute__((format (printf, 2, 3)))
215 void		 log_err(struct client*, const char*, ...)	LOG_ATTR_FMT;
216 void		 log_warn(struct client*, const char*, ...)	LOG_ATTR_FMT;
217 void		 log_notice(struct client*, const char*, ...)	LOG_ATTR_FMT;
218 void		 log_info(struct client*, const char*, ...)	LOG_ATTR_FMT;
219 void		 log_debug(struct client*, const char*, ...)	LOG_ATTR_FMT;
220 void		 log_request(struct client*, char*, size_t);
221 
222 /* mime.c */
223 void		 init_mime(struct mime*);
224 void		 add_mime(struct mime*, const char*, const char*);
225 void		 load_default_mime(struct mime*);
226 const char	*mime(struct vhost*, const char*);
227 
228 /* server.c */
229 const char	*vhost_lang(struct vhost*, const char*);
230 const char	*vhost_default_mime(struct vhost*, const char*);
231 const char	*vhost_index(struct vhost*, const char*);
232 int		 vhost_auto_index(struct vhost*, const char*);
233 int		 vhost_block_return(struct vhost*, const char*, int*, const char**);
234 int		 vhost_strip(struct vhost*, const char*);
235 X509_STORE	*vhost_require_ca(struct vhost*, const char*);
236 void		 mark_nonblock(int);
237 void		 loop(struct tls*, int, int);
238 
239 /* ex.c */
240 int		 send_string(int, const char*);
241 int		 recv_string(int, char**);
242 int		 send_iri(int, struct iri*);
243 int		 recv_iri(int, struct iri*);
244 void		 free_recvd_iri(struct iri*);
245 int		 send_vhost(int, struct vhost*);
246 int		 recv_vhost(int, struct vhost**);
247 int		 send_time(int, time_t);
248 int		 recv_time(int, time_t*);
249 int		 send_fd(int, int);
250 int		 recv_fd(int);
251 int		 executor_main(void);
252 
253 /* sandbox.c */
254 void		 sandbox(void);
255 
256 /* utf8.c */
257 int		 valid_multibyte_utf8(struct parser*);
258 char		*utf8_nth(char*, size_t);
259 
260 /* iri.c */
261 int		 parse_iri(char*, struct iri*, const char**);
262 int		 trim_req_iri(char*, const char **);
263 int		 serialize_iri(struct iri*, char*, size_t);
264 char		*pct_decode_str(char *);
265 
266 /* puny.c */
267 int		 puny_decode(const char*, char*, size_t, const char**);
268 
269 /* utils.c */
270 void		 block_signals(void);
271 void		 unblock_signals(void);
272 int		 starts_with(const char*, const char*);
273 int		 ends_with(const char*, const char*);
274 ssize_t		 filesize(int);
275 char		*absolutify_path(const char*);
276 char		*xstrdup(const char*);
277 void		 gen_certificate(const char*, const char*, const char*);
278 X509_STORE	*load_ca(const char*);
279 int		 validate_against_ca(X509_STORE*, const uint8_t*, size_t);
280 
281 #endif