1 /*
2  * Copyright (c) 2021 Matthias Schmidt <xhr@giessen.ccc.de>
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 <sys/socket.h>
18 #include <sys/stat.h>
19 
20 #include <err.h>
21 #include <errno.h>
22 #include <fcntl.h>
23 #include <stdio.h>
24 #include <string.h>
25 #include <unistd.h>
26 
27 #include "log.h"
28 #include "twind.h"
29 
30 static void
31 generate_meta(int status_code, char *meta_response_string, const char *mime)
32 {
33 	switch(status_code) {
34 		case STATUS_INPUT:
35 			snprintf(meta_response_string, 1024, "%d Present input\r\n", status_code);
36 			break;
37 		case STATUS_SENSITIVE_INPUT:
38 			snprintf(meta_response_string, 1024, "%d Present sensitive input\r\n",
39 				status_code);
40 			break;
41 		case STATUS_SUCCESS:
42 			if (mime == NULL)
43 				/* Could not deducte mime type, so send text/gemini as default */
44 				snprintf(meta_response_string, 1024, "%d text/gemini\r\n", status_code);
45 			else
46 				snprintf(meta_response_string, 1024, "%d %s\r\n", status_code, mime);
47 			break;
48 		case STATUS_REDIRECT_TEMP:
49 			snprintf(meta_response_string, 1024, "%d Temporary redirect\r\n",
50 				status_code);
51 			break;
52 		case STATUS_REDIRECT_PERM:
53 			snprintf(meta_response_string, 1024, "%d Permanent redirect\r\n",
54 				status_code);
55 			break;
56 		case STATUS_TEMP_UNAVAILABLE:
57 			snprintf(meta_response_string, 1024, "%d Temporary failure\r\n",
58 				status_code);
59 			break;
60 		case STATUS_SERVER_UNAVAILABLE:
61 			snprintf(meta_response_string, 1024, "%d Server unavailable\r\n",
62 				status_code);
63 			break;
64 		case STATUS_CGI_ERROR:
65 			snprintf(meta_response_string, 1024, "%d CGI Error\r\n", status_code);
66 			break;
67 		case STATUS_PROXY_ERROR:
68 			snprintf(meta_response_string, 1024, "%d Proxy error\r\n", status_code);
69 			break;
70 		case STATUS_SLOW_DOWN:
71 			snprintf(meta_response_string, 1024, "%d Slow down\r\n", status_code);
72 			break;
73 		case STATUS_PERM_FAILURE:
74 			snprintf(meta_response_string, 1024, "%d Permanent failure\r\n", status_code);
75 			break;
76 		case STATUS_NOT_FOUND:
77 			snprintf(meta_response_string, 1024, "%d Resource not found\r\n",
78 				status_code);
79 			break;
80 		case STATUS_GONE:
81 			snprintf(meta_response_string, 1024, "%d Resource is gone\r\n", status_code);
82 			break;
83 		case STATUS_PROXY_REQUEST_REFUSED:
84 			snprintf(meta_response_string, 1024, "%d Proxy request refused\r\n",
85 				status_code);
86 			break;
87 		case STATUS_BAD_REQUEST:
88 			snprintf(meta_response_string, 1024, "%d Bad Request\r\n", status_code);
89 			break;
90 		case STATUS_CLIENT_CERT_REQUIRED:
91 			snprintf(meta_response_string, 1024, "%d Client Certificate Required\r\n",
92 				status_code);
93 			break;
94 		case STATUS_CERT_NOT_AUTHORIZED:
95 			snprintf(meta_response_string, 1024, "%d Certificate not authorized\r\n",
96 				status_code);
97 			break;
98 		case STATUS_CERT_NOT_VALID:
99 			snprintf(meta_response_string, 1024, "%d Certificate not valid\r\n",
100 				status_code);
101 			break;
102 		default:
103 			snprintf(meta_response_string, 1024, "%d Unkown status code\r\n",
104 				status_code);
105 			break;
106 	}
107 }
108 
109 int
110 send_non_success_response(SSL *ssl_peer, int status_code)
111 {
112 	char meta[1024];
113 
114 	memset(meta, 0, sizeof(meta));
115 
116 	generate_meta(status_code, meta, NULL);
117 
118 	log_debug("Send non success response to client: %d", status_code);
119 
120 	if (SSL_write(ssl_peer, meta, strlen(meta)) <= 0) {
121 		log_warn("Could not send response to client");
122 		return -1;
123 	}
124 
125 	return 0;
126 }
127 
128 int
129 send_response(SSL *ssl_peer, int status_code, const char *gemini_file_path,
130 	const char *mime)
131 {
132 	char meta[1024];
133 	char buffer[1024];
134 	int fd = -1, len;
135 
136 	// <STATUS><SPACE><META><CR><LF>
137 
138 	memset(meta, 0, sizeof(meta));
139 	memset(buffer, 0, sizeof(buffer));
140 
141 	generate_meta(status_code, meta, mime);
142 
143 	if (SSL_write(ssl_peer, meta, strlen(meta)) <= 0) {
144 		log_warn("Could not send response to client");
145 		return -1;
146 	}
147 
148 	/* Close connection and do not send a response if status code is not
149 	 * a SUCCESS code
150 	 */
151 	if (status_code < 30 && status_code >= 20) {
152 		fd = open(gemini_file_path, O_RDONLY);
153 		if (fd == -1) {
154 			log_warn("Cannot open requested file");
155 			goto out;
156 		}
157 
158 		while ((len = read(fd, buffer, sizeof(buffer)-1)) > 0) {
159 			if (SSL_write(ssl_peer, buffer, len) <= 0) {
160 				log_warn("Could not send response to client");
161 				return -1;
162 			}
163 		}
164 	}
165 
166 out:
167 	close(fd);
168 
169 	return 0;
170 }
171 
172 int
173 check_gemini_file(const char *gemini_file_path)
174 {
175 	struct stat sb;
176 
177 	if (stat(gemini_file_path, &sb) == -1) {
178 		log_warn("Cannot open requested file");
179 		return -1;
180 	}
181 
182 	if ((sb.st_mode & (S_IRUSR | S_IRGRP | S_IROTH)) == 0) {
183 		log_warn("Cannot read requested file");
184 		return -1;
185 	}
186 
187 	if ((sb.st_mode & S_IFMT) == S_IFDIR)
188 		return 1;
189 
190 	return 0;
191 }