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ee40139d MT |
1 | /* This file is part of the IPFire Firewall. |
2 | * | |
3 | * This program is distributed under the terms of the GNU General Public | |
4 | * Licence. See the file COPYING for details. */ | |
5 | ||
7ef66b61 MT |
6 | #define _BSD_SOURCE |
7 | #define _XOPEN_SOURCE | |
8 | ||
ee40139d MT |
9 | #include <stdio.h> |
10 | #include <stdlib.h> | |
11 | #include <string.h> | |
7ef66b61 | 12 | #include <time.h> |
ee40139d MT |
13 | |
14 | #include "libsmooth.h" | |
15 | #include "setuid.h" | |
16 | ||
17 | #define CAPTIVE_PORTAL_SETTINGS CONFIG_ROOT "/captive/settings" | |
18 | #define ETHERNET_SETTINGS CONFIG_ROOT "/ethernet/settings" | |
19 | ||
20 | #define CLIENTS CONFIG_ROOT "/captive/clients" | |
21 | #define IPTABLES "/sbin/iptables --wait" | |
22 | #define HTTP_PORT 80 | |
23 | #define REDIRECT_PORT 1013 | |
24 | ||
25 | typedef struct client { | |
26 | char etheraddr[STRING_SIZE]; | |
27 | char ipaddr[STRING_SIZE]; | |
7ef66b61 MT |
28 | time_t time_start; |
29 | int expires; | |
ee40139d MT |
30 | |
31 | struct client* next; | |
32 | } client_t; | |
33 | ||
7ef66b61 MT |
34 | static time_t parse_time(const char* s) { |
35 | int t = 0; | |
ee40139d | 36 | |
7ef66b61 MT |
37 | if (sscanf(s, "%d", &t) == 1) { |
38 | return (time_t)t; | |
ee40139d MT |
39 | } |
40 | ||
41 | return -1; | |
42 | } | |
43 | ||
7ef66b61 | 44 | static char* format_time(const time_t* t) { |
ee40139d | 45 | char buffer[STRING_SIZE]; |
7ef66b61 MT |
46 | |
47 | struct tm* tm = gmtime(t); | |
48 | if (tm == NULL) | |
49 | return NULL; | |
50 | ||
51 | strftime(buffer, sizeof(buffer), "%Y-%m-%dT%H:%M", tm); | |
ee40139d MT |
52 | |
53 | return strdup(buffer); | |
54 | } | |
55 | ||
56 | static client_t* read_clients(char* filename) { | |
57 | FILE* f = NULL; | |
58 | ||
59 | if (!(f = fopen(filename, "r"))) { | |
60 | fprintf(stderr, "Could not open configuration file: %s\n", filename); | |
61 | return NULL;; | |
62 | } | |
63 | ||
64 | char line[STRING_SIZE]; | |
65 | ||
66 | client_t* client_first = NULL; | |
67 | client_t* client_last = NULL; | |
68 | client_t* client_curr; | |
69 | ||
70 | while ((fgets(line, STRING_SIZE, f) != NULL)) { | |
71 | if (line[strlen(line) - 1] == '\n') | |
72 | line[strlen(line) - 1] = '\0'; | |
73 | ||
76ece323 MT |
74 | // Skip all commented lines |
75 | if (*line == '#') | |
76 | continue; | |
77 | ||
ee40139d MT |
78 | client_curr = (client_t*)malloc(sizeof(client_t)); |
79 | memset(client_curr, 0, sizeof(client_t)); | |
80 | ||
81 | if (client_first == NULL) | |
82 | client_first = client_curr; | |
83 | else | |
84 | client_last->next = client_curr; | |
85 | client_last = client_curr; | |
86 | ||
87 | unsigned int count = 0; | |
88 | char* lineptr = line; | |
89 | while (1) { | |
90 | if (!*lineptr) | |
91 | break; | |
92 | ||
93 | char* word = lineptr; | |
94 | while (*lineptr != '\0') { | |
95 | if (*lineptr == ',') { | |
96 | *lineptr = '\0'; | |
97 | lineptr++; | |
98 | break; | |
99 | } | |
100 | lineptr++; | |
101 | } | |
102 | ||
103 | switch (count++) { | |
104 | // Ethernet address | |
105 | case 1: | |
106 | strcpy(client_curr->etheraddr, word); | |
107 | break; | |
108 | ||
109 | // IP address | |
110 | case 2: | |
111 | strcpy(client_curr->ipaddr, word); | |
112 | break; | |
113 | ||
114 | // Start time | |
115 | case 3: | |
116 | client_curr->time_start = parse_time(word); | |
117 | break; | |
118 | ||
7ef66b61 | 119 | // Expire duration |
ee40139d | 120 | case 4: |
7ef66b61 | 121 | client_curr->expires = atoi(word); |
ee40139d MT |
122 | break; |
123 | ||
124 | default: | |
125 | break; | |
126 | } | |
127 | } | |
128 | } | |
129 | ||
130 | if (f) | |
131 | fclose(f); | |
132 | ||
133 | return client_first; | |
134 | } | |
135 | ||
136 | static void flush_chains() { | |
137 | // filter | |
138 | safe_system(IPTABLES " -F CAPTIVE_PORTAL"); | |
139 | safe_system(IPTABLES " -F CAPTIVE_PORTAL_CLIENTS"); | |
140 | ||
141 | // nat | |
142 | safe_system(IPTABLES " -t nat -F CAPTIVE_PORTAL"); | |
143 | } | |
144 | ||
fb1d26d1 MT |
145 | static int setup_dns_filters() { |
146 | const char* protos[] = { "udp", "tcp", NULL }; | |
147 | ||
148 | // Limits the number of DNS requests to 3 kByte/s | |
149 | // A burst of 1MB is permitted at the start | |
150 | const char* limiter = "-m hashlimit --hashlimit-name dns-filter" | |
151 | " --hashlimit-mode srcip --hashlimit-upto 3kb/sec --hashlimit-burst 1024kb"; | |
152 | ||
153 | char command[STRING_SIZE]; | |
154 | ||
155 | const char** proto = protos; | |
156 | while (*proto) { | |
157 | snprintf(command, sizeof(command), IPTABLES " -A CAPTIVE_PORTAL_CLIENTS -p %s" | |
158 | " --dport 53 %s -j RETURN", *proto, limiter); | |
159 | ||
160 | int r = safe_system(command); | |
161 | if (r) | |
162 | return r; | |
163 | ||
164 | proto++; | |
165 | } | |
166 | ||
167 | return 0; | |
168 | } | |
169 | ||
ee40139d MT |
170 | static int add_client_rules(const client_t* clients) { |
171 | char command[STRING_SIZE]; | |
172 | char match[STRING_SIZE]; | |
173 | ||
174 | while (clients) { | |
5fbeaf13 MT |
175 | size_t len = 0; |
176 | ||
0c24f0a9 | 177 | if (*clients->ipaddr && clients->expires > 0) { |
5fbeaf13 MT |
178 | len += snprintf(match + len, sizeof(match) - len, |
179 | "-s %s", clients->ipaddr); | |
180 | } | |
181 | ||
182 | len += snprintf(match + len, sizeof(match) - len, | |
0c24f0a9 MT |
183 | " -m mac --mac-source %s", clients->etheraddr); |
184 | ||
185 | if (clients->expires > 0) { | |
186 | time_t expires = clients->time_start + clients->expires; | |
187 | ||
188 | char* time_start = format_time(&clients->time_start); | |
189 | char* time_end = format_time(&expires); | |
ee40139d | 190 | |
0c24f0a9 | 191 | len += snprintf(match + len, sizeof(match) - len, |
0d6a599a | 192 | " -m time --datestart %s --datestop %s", |
0c24f0a9 MT |
193 | time_start, time_end); |
194 | ||
195 | free(time_start); | |
196 | free(time_end); | |
197 | } | |
ee40139d MT |
198 | |
199 | // filter | |
200 | snprintf(command, sizeof(command), IPTABLES " -A CAPTIVE_PORTAL_CLIENTS" | |
201 | " %s -j RETURN", match); | |
202 | safe_system(command); | |
203 | ||
204 | // nat | |
205 | snprintf(command, sizeof(command), IPTABLES " -t nat -A CAPTIVE_PORTAL" | |
206 | " %s -j RETURN", match); | |
207 | safe_system(command); | |
208 | ||
209 | // Move on to the next client | |
210 | clients = clients->next; | |
211 | } | |
212 | ||
213 | return 0; | |
214 | } | |
215 | ||
216 | static char* get_key(struct keyvalue* settings, char* key) { | |
217 | char value[STRING_SIZE]; | |
218 | ||
219 | if (!findkey(settings, key, value)) | |
220 | return NULL; | |
221 | ||
222 | return strdup(value); | |
223 | } | |
224 | ||
225 | static int add_interface_rule(const char* intf, int allow_webif_access) { | |
226 | int r; | |
227 | char command[STRING_SIZE]; | |
228 | ||
229 | if ((intf == NULL) || (strlen(intf) == 0)) { | |
230 | fprintf(stderr, "Empty interface given\n"); | |
231 | return -1; | |
232 | } | |
233 | ||
234 | snprintf(command, sizeof(command), IPTABLES " -A CAPTIVE_PORTAL -i %s" | |
235 | " -j CAPTIVE_PORTAL_CLIENTS", intf); | |
236 | r = safe_system(command); | |
237 | if (r) | |
238 | return r; | |
239 | ||
ee40139d MT |
240 | if (allow_webif_access) { |
241 | snprintf(command, sizeof(command), IPTABLES " -A CAPTIVE_PORTAL_CLIENTS" | |
242 | " -i %s -p tcp --dport 444 -j RETURN", intf); | |
243 | r = safe_system(command); | |
244 | if (r) | |
245 | return r; | |
246 | } | |
247 | ||
248 | // Redirect all unauthenticated clients | |
249 | snprintf(command, sizeof(command), IPTABLES " -t nat -A CAPTIVE_PORTAL -i %s" | |
250 | " -p tcp --dport %d -j REDIRECT --to-ports %d", intf, HTTP_PORT, REDIRECT_PORT); | |
251 | r = safe_system(command); | |
252 | if (r) | |
253 | return r; | |
254 | ||
abc41f02 MT |
255 | // Allow access to captive portal site |
256 | snprintf(command, sizeof(command), IPTABLES " -A CAPTIVE_PORTAL_CLIENTS" | |
5511fa31 | 257 | " -i %s -p tcp --dport %d -j RETURN", intf, REDIRECT_PORT); |
abc41f02 MT |
258 | r = safe_system(command); |
259 | if (r) | |
260 | return r; | |
261 | ||
ee40139d MT |
262 | return 0; |
263 | } | |
264 | ||
265 | static int add_interface_rules(struct keyvalue* captive_portal_settings, struct keyvalue* ethernet_settings) { | |
266 | const char* intf; | |
267 | char* setting; | |
268 | int r = 0; | |
269 | ||
270 | setting = get_key(captive_portal_settings, "ENABLE_GREEN"); | |
271 | if (setting && (strcmp(setting, "on") == 0)) { | |
272 | free(setting); | |
273 | ||
274 | intf = get_key(ethernet_settings, "GREEN_DEV"); | |
275 | r = add_interface_rule(intf, /* allow webif access from green */ 1); | |
276 | if (r) | |
277 | return r; | |
278 | } | |
279 | ||
280 | setting = get_key(captive_portal_settings, "ENABLE_BLUE"); | |
281 | if (setting && (strcmp(setting, "on") == 0)) { | |
282 | free(setting); | |
283 | ||
284 | intf = get_key(ethernet_settings, "BLUE_DEV"); | |
285 | r = add_interface_rule(intf, /* do not allow webif access */ 0); | |
286 | if (r) | |
287 | return r; | |
288 | } | |
289 | ||
290 | // Always pass DNS packets through all firewall rules | |
fb1d26d1 | 291 | r = setup_dns_filters(); |
ee40139d MT |
292 | if (r) |
293 | return r; | |
294 | ||
ee40139d MT |
295 | // Add the last rule |
296 | r = safe_system(IPTABLES " -A CAPTIVE_PORTAL_CLIENTS -j DROP"); | |
297 | if (r) | |
298 | return r; | |
299 | ||
300 | return r; | |
301 | } | |
302 | ||
303 | int main(int argc, char** argv) { | |
304 | int r = 0; | |
305 | char* intf = NULL; | |
306 | client_t* clients = NULL; | |
307 | ||
cec16b82 MT |
308 | struct keyvalue* captive_portal_settings = NULL; |
309 | struct keyvalue* ethernet_settings = NULL; | |
310 | ||
ee40139d MT |
311 | if (!(initsetuid())) |
312 | exit(2); | |
313 | ||
cec16b82 | 314 | ethernet_settings = initkeyvalues(); |
ee40139d MT |
315 | if (!readkeyvalues(ethernet_settings, ETHERNET_SETTINGS)) { |
316 | fprintf(stderr, "Could not read %s\n", ETHERNET_SETTINGS); | |
317 | r = 1; | |
318 | goto END; | |
319 | } | |
320 | ||
cec16b82 | 321 | captive_portal_settings = initkeyvalues(); |
ee40139d MT |
322 | if (!readkeyvalues(captive_portal_settings, CAPTIVE_PORTAL_SETTINGS)) { |
323 | fprintf(stderr, "Could not read %s\n", CAPTIVE_PORTAL_SETTINGS); | |
324 | r = 1; | |
325 | goto END; | |
326 | } | |
327 | ||
328 | clients = read_clients(CLIENTS); | |
329 | ||
330 | // Clean up all old rules | |
331 | flush_chains(); | |
332 | ||
333 | // Add all client rules | |
334 | r = add_client_rules(clients); | |
335 | if (r) | |
336 | goto END; | |
337 | ||
338 | // Add all interface rules | |
339 | r = add_interface_rules(captive_portal_settings, ethernet_settings); | |
340 | if (r) | |
341 | goto END; | |
342 | ||
343 | END: | |
344 | while (clients) { | |
345 | client_t* head = clients; | |
346 | clients = clients->next; | |
347 | ||
348 | free(head); | |
349 | } | |
350 | ||
351 | if (ethernet_settings) | |
352 | freekeyvalues(ethernet_settings); | |
353 | ||
354 | if (captive_portal_settings) | |
355 | freekeyvalues(captive_portal_settings); | |
356 | ||
357 | if (intf) | |
358 | free(intf); | |
359 | ||
360 | return r; | |
361 | } |