Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * ebtables | |
3 | * | |
4 | * Author: | |
5 | * Bart De Schuymer <bdschuym@pandora.be> | |
6 | * | |
7 | * ebtables.c,v 2.0, July, 2002 | |
8 | * | |
9 | * This code is stongly inspired on the iptables code which is | |
10 | * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling | |
11 | * | |
12 | * This program is free software; you can redistribute it and/or | |
13 | * modify it under the terms of the GNU General Public License | |
14 | * as published by the Free Software Foundation; either version | |
15 | * 2 of the License, or (at your option) any later version. | |
16 | */ | |
17 | ||
18 | /* used for print_string */ | |
19 | #include <linux/sched.h> | |
20 | #include <linux/tty.h> | |
21 | ||
22 | #include <linux/kmod.h> | |
23 | #include <linux/module.h> | |
24 | #include <linux/vmalloc.h> | |
25 | #include <linux/netfilter_bridge/ebtables.h> | |
26 | #include <linux/spinlock.h> | |
df0933dc | 27 | #include <linux/mutex.h> |
1da177e4 LT |
28 | #include <asm/uaccess.h> |
29 | #include <linux/smp.h> | |
c8923c6b | 30 | #include <linux/cpumask.h> |
1da177e4 LT |
31 | #include <net/sock.h> |
32 | /* needed for logical [in,out]-dev filtering */ | |
33 | #include "../br_private.h" | |
34 | ||
1da177e4 LT |
35 | #define BUGPRINT(format, args...) printk("kernel msg: ebtables bug: please "\ |
36 | "report to author: "format, ## args) | |
37 | /* #define BUGPRINT(format, args...) */ | |
1da177e4 LT |
38 | #define MEMPRINT(format, args...) printk("kernel msg: ebtables "\ |
39 | ": out of memory: "format, ## args) | |
40 | /* #define MEMPRINT(format, args...) */ | |
41 | ||
42 | ||
43 | ||
44 | /* | |
45 | * Each cpu has its own set of counters, so there is no need for write_lock in | |
46 | * the softirq | |
47 | * For reading or updating the counters, the user context needs to | |
48 | * get a write_lock | |
49 | */ | |
50 | ||
51 | /* The size of each set of counters is altered to get cache alignment */ | |
52 | #define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1)) | |
53 | #define COUNTER_OFFSET(n) (SMP_ALIGN(n * sizeof(struct ebt_counter))) | |
54 | #define COUNTER_BASE(c, n, cpu) ((struct ebt_counter *)(((char *)c) + \ | |
55 | COUNTER_OFFSET(n) * cpu)) | |
56 | ||
57 | ||
58 | ||
57b47a53 | 59 | static DEFINE_MUTEX(ebt_mutex); |
1da177e4 LT |
60 | static LIST_HEAD(ebt_tables); |
61 | static LIST_HEAD(ebt_targets); | |
62 | static LIST_HEAD(ebt_matches); | |
63 | static LIST_HEAD(ebt_watchers); | |
64 | ||
65 | static struct ebt_target ebt_standard_target = | |
66 | { {NULL, NULL}, EBT_STANDARD_TARGET, NULL, NULL, NULL, NULL}; | |
67 | ||
68 | static inline int ebt_do_watcher (struct ebt_entry_watcher *w, | |
69 | const struct sk_buff *skb, unsigned int hooknr, const struct net_device *in, | |
70 | const struct net_device *out) | |
71 | { | |
72 | w->u.watcher->watcher(skb, hooknr, in, out, w->data, | |
73 | w->watcher_size); | |
74 | /* watchers don't give a verdict */ | |
75 | return 0; | |
76 | } | |
77 | ||
78 | static inline int ebt_do_match (struct ebt_entry_match *m, | |
79 | const struct sk_buff *skb, const struct net_device *in, | |
80 | const struct net_device *out) | |
81 | { | |
82 | return m->u.match->match(skb, in, out, m->data, | |
83 | m->match_size); | |
84 | } | |
85 | ||
86 | static inline int ebt_dev_check(char *entry, const struct net_device *device) | |
87 | { | |
88 | int i = 0; | |
6f5b7ef6 | 89 | const char *devname = device->name; |
1da177e4 LT |
90 | |
91 | if (*entry == '\0') | |
92 | return 0; | |
93 | if (!device) | |
94 | return 1; | |
95 | /* 1 is the wildcard token */ | |
96 | while (entry[i] != '\0' && entry[i] != 1 && entry[i] == devname[i]) | |
97 | i++; | |
98 | return (devname[i] != entry[i] && entry[i] != 1); | |
99 | } | |
100 | ||
101 | #define FWINV2(bool,invflg) ((bool) ^ !!(e->invflags & invflg)) | |
102 | /* process standard matches */ | |
103 | static inline int ebt_basic_match(struct ebt_entry *e, struct ethhdr *h, | |
104 | const struct net_device *in, const struct net_device *out) | |
105 | { | |
106 | int verdict, i; | |
107 | ||
108 | if (e->bitmask & EBT_802_3) { | |
109 | if (FWINV2(ntohs(h->h_proto) >= 1536, EBT_IPROTO)) | |
110 | return 1; | |
111 | } else if (!(e->bitmask & EBT_NOPROTO) && | |
112 | FWINV2(e->ethproto != h->h_proto, EBT_IPROTO)) | |
113 | return 1; | |
114 | ||
115 | if (FWINV2(ebt_dev_check(e->in, in), EBT_IIN)) | |
116 | return 1; | |
117 | if (FWINV2(ebt_dev_check(e->out, out), EBT_IOUT)) | |
118 | return 1; | |
119 | if ((!in || !in->br_port) ? 0 : FWINV2(ebt_dev_check( | |
120 | e->logical_in, in->br_port->br->dev), EBT_ILOGICALIN)) | |
121 | return 1; | |
122 | if ((!out || !out->br_port) ? 0 : FWINV2(ebt_dev_check( | |
123 | e->logical_out, out->br_port->br->dev), EBT_ILOGICALOUT)) | |
124 | return 1; | |
125 | ||
126 | if (e->bitmask & EBT_SOURCEMAC) { | |
127 | verdict = 0; | |
128 | for (i = 0; i < 6; i++) | |
129 | verdict |= (h->h_source[i] ^ e->sourcemac[i]) & | |
130 | e->sourcemsk[i]; | |
131 | if (FWINV2(verdict != 0, EBT_ISOURCE) ) | |
132 | return 1; | |
133 | } | |
134 | if (e->bitmask & EBT_DESTMAC) { | |
135 | verdict = 0; | |
136 | for (i = 0; i < 6; i++) | |
137 | verdict |= (h->h_dest[i] ^ e->destmac[i]) & | |
138 | e->destmsk[i]; | |
139 | if (FWINV2(verdict != 0, EBT_IDEST) ) | |
140 | return 1; | |
141 | } | |
142 | return 0; | |
143 | } | |
144 | ||
145 | /* Do some firewalling */ | |
146 | unsigned int ebt_do_table (unsigned int hook, struct sk_buff **pskb, | |
147 | const struct net_device *in, const struct net_device *out, | |
148 | struct ebt_table *table) | |
149 | { | |
150 | int i, nentries; | |
151 | struct ebt_entry *point; | |
152 | struct ebt_counter *counter_base, *cb_base; | |
153 | struct ebt_entry_target *t; | |
154 | int verdict, sp = 0; | |
155 | struct ebt_chainstack *cs; | |
156 | struct ebt_entries *chaininfo; | |
157 | char *base; | |
158 | struct ebt_table_info *private; | |
159 | ||
160 | read_lock_bh(&table->lock); | |
161 | private = table->private; | |
162 | cb_base = COUNTER_BASE(private->counters, private->nentries, | |
163 | smp_processor_id()); | |
164 | if (private->chainstack) | |
165 | cs = private->chainstack[smp_processor_id()]; | |
166 | else | |
167 | cs = NULL; | |
168 | chaininfo = private->hook_entry[hook]; | |
169 | nentries = private->hook_entry[hook]->nentries; | |
170 | point = (struct ebt_entry *)(private->hook_entry[hook]->data); | |
171 | counter_base = cb_base + private->hook_entry[hook]->counter_offset; | |
172 | /* base for chain jumps */ | |
173 | base = private->entries; | |
174 | i = 0; | |
175 | while (i < nentries) { | |
176 | if (ebt_basic_match(point, eth_hdr(*pskb), in, out)) | |
177 | goto letscontinue; | |
178 | ||
179 | if (EBT_MATCH_ITERATE(point, ebt_do_match, *pskb, in, out) != 0) | |
180 | goto letscontinue; | |
181 | ||
182 | /* increase counter */ | |
183 | (*(counter_base + i)).pcnt++; | |
184 | (*(counter_base + i)).bcnt+=(**pskb).len; | |
185 | ||
186 | /* these should only watch: not modify, nor tell us | |
187 | what to do with the packet */ | |
188 | EBT_WATCHER_ITERATE(point, ebt_do_watcher, *pskb, hook, in, | |
189 | out); | |
190 | ||
191 | t = (struct ebt_entry_target *) | |
192 | (((char *)point) + point->target_offset); | |
193 | /* standard target */ | |
194 | if (!t->u.target->target) | |
195 | verdict = ((struct ebt_standard_target *)t)->verdict; | |
196 | else | |
197 | verdict = t->u.target->target(pskb, hook, | |
198 | in, out, t->data, t->target_size); | |
199 | if (verdict == EBT_ACCEPT) { | |
200 | read_unlock_bh(&table->lock); | |
201 | return NF_ACCEPT; | |
202 | } | |
203 | if (verdict == EBT_DROP) { | |
204 | read_unlock_bh(&table->lock); | |
205 | return NF_DROP; | |
206 | } | |
207 | if (verdict == EBT_RETURN) { | |
208 | letsreturn: | |
209 | #ifdef CONFIG_NETFILTER_DEBUG | |
210 | if (sp == 0) { | |
211 | BUGPRINT("RETURN on base chain"); | |
212 | /* act like this is EBT_CONTINUE */ | |
213 | goto letscontinue; | |
214 | } | |
215 | #endif | |
216 | sp--; | |
217 | /* put all the local variables right */ | |
218 | i = cs[sp].n; | |
219 | chaininfo = cs[sp].chaininfo; | |
220 | nentries = chaininfo->nentries; | |
221 | point = cs[sp].e; | |
222 | counter_base = cb_base + | |
223 | chaininfo->counter_offset; | |
224 | continue; | |
225 | } | |
226 | if (verdict == EBT_CONTINUE) | |
227 | goto letscontinue; | |
228 | #ifdef CONFIG_NETFILTER_DEBUG | |
229 | if (verdict < 0) { | |
230 | BUGPRINT("bogus standard verdict\n"); | |
231 | read_unlock_bh(&table->lock); | |
232 | return NF_DROP; | |
233 | } | |
234 | #endif | |
235 | /* jump to a udc */ | |
236 | cs[sp].n = i + 1; | |
237 | cs[sp].chaininfo = chaininfo; | |
238 | cs[sp].e = (struct ebt_entry *) | |
239 | (((char *)point) + point->next_offset); | |
240 | i = 0; | |
241 | chaininfo = (struct ebt_entries *) (base + verdict); | |
242 | #ifdef CONFIG_NETFILTER_DEBUG | |
243 | if (chaininfo->distinguisher) { | |
244 | BUGPRINT("jump to non-chain\n"); | |
245 | read_unlock_bh(&table->lock); | |
246 | return NF_DROP; | |
247 | } | |
248 | #endif | |
249 | nentries = chaininfo->nentries; | |
250 | point = (struct ebt_entry *)chaininfo->data; | |
251 | counter_base = cb_base + chaininfo->counter_offset; | |
252 | sp++; | |
253 | continue; | |
254 | letscontinue: | |
255 | point = (struct ebt_entry *) | |
256 | (((char *)point) + point->next_offset); | |
257 | i++; | |
258 | } | |
259 | ||
260 | /* I actually like this :) */ | |
261 | if (chaininfo->policy == EBT_RETURN) | |
262 | goto letsreturn; | |
263 | if (chaininfo->policy == EBT_ACCEPT) { | |
264 | read_unlock_bh(&table->lock); | |
265 | return NF_ACCEPT; | |
266 | } | |
267 | read_unlock_bh(&table->lock); | |
268 | return NF_DROP; | |
269 | } | |
270 | ||
271 | /* If it succeeds, returns element and locks mutex */ | |
272 | static inline void * | |
273 | find_inlist_lock_noload(struct list_head *head, const char *name, int *error, | |
57b47a53 | 274 | struct mutex *mutex) |
1da177e4 | 275 | { |
df0933dc PM |
276 | struct { |
277 | struct list_head list; | |
278 | char name[EBT_FUNCTION_MAXNAMELEN]; | |
279 | } *e; | |
1da177e4 | 280 | |
57b47a53 | 281 | *error = mutex_lock_interruptible(mutex); |
1da177e4 LT |
282 | if (*error != 0) |
283 | return NULL; | |
284 | ||
df0933dc PM |
285 | list_for_each_entry(e, head, list) { |
286 | if (strcmp(e->name, name) == 0) | |
287 | return e; | |
1da177e4 | 288 | } |
df0933dc PM |
289 | *error = -ENOENT; |
290 | mutex_unlock(mutex); | |
291 | return NULL; | |
1da177e4 LT |
292 | } |
293 | ||
294 | #ifndef CONFIG_KMOD | |
295 | #define find_inlist_lock(h,n,p,e,m) find_inlist_lock_noload((h),(n),(e),(m)) | |
296 | #else | |
297 | static void * | |
298 | find_inlist_lock(struct list_head *head, const char *name, const char *prefix, | |
57b47a53 | 299 | int *error, struct mutex *mutex) |
1da177e4 LT |
300 | { |
301 | void *ret; | |
302 | ||
303 | ret = find_inlist_lock_noload(head, name, error, mutex); | |
304 | if (!ret) { | |
305 | request_module("%s%s", prefix, name); | |
306 | ret = find_inlist_lock_noload(head, name, error, mutex); | |
307 | } | |
308 | return ret; | |
309 | } | |
310 | #endif | |
311 | ||
312 | static inline struct ebt_table * | |
57b47a53 | 313 | find_table_lock(const char *name, int *error, struct mutex *mutex) |
1da177e4 LT |
314 | { |
315 | return find_inlist_lock(&ebt_tables, name, "ebtable_", error, mutex); | |
316 | } | |
317 | ||
318 | static inline struct ebt_match * | |
57b47a53 | 319 | find_match_lock(const char *name, int *error, struct mutex *mutex) |
1da177e4 LT |
320 | { |
321 | return find_inlist_lock(&ebt_matches, name, "ebt_", error, mutex); | |
322 | } | |
323 | ||
324 | static inline struct ebt_watcher * | |
57b47a53 | 325 | find_watcher_lock(const char *name, int *error, struct mutex *mutex) |
1da177e4 LT |
326 | { |
327 | return find_inlist_lock(&ebt_watchers, name, "ebt_", error, mutex); | |
328 | } | |
329 | ||
330 | static inline struct ebt_target * | |
57b47a53 | 331 | find_target_lock(const char *name, int *error, struct mutex *mutex) |
1da177e4 LT |
332 | { |
333 | return find_inlist_lock(&ebt_targets, name, "ebt_", error, mutex); | |
334 | } | |
335 | ||
336 | static inline int | |
337 | ebt_check_match(struct ebt_entry_match *m, struct ebt_entry *e, | |
338 | const char *name, unsigned int hookmask, unsigned int *cnt) | |
339 | { | |
340 | struct ebt_match *match; | |
14197d54 | 341 | size_t left = ((char *)e + e->watchers_offset) - (char *)m; |
1da177e4 LT |
342 | int ret; |
343 | ||
14197d54 AV |
344 | if (left < sizeof(struct ebt_entry_match) || |
345 | left - sizeof(struct ebt_entry_match) < m->match_size) | |
1da177e4 LT |
346 | return -EINVAL; |
347 | match = find_match_lock(m->u.name, &ret, &ebt_mutex); | |
348 | if (!match) | |
349 | return ret; | |
350 | m->u.match = match; | |
351 | if (!try_module_get(match->me)) { | |
57b47a53 | 352 | mutex_unlock(&ebt_mutex); |
1da177e4 LT |
353 | return -ENOENT; |
354 | } | |
57b47a53 | 355 | mutex_unlock(&ebt_mutex); |
1da177e4 LT |
356 | if (match->check && |
357 | match->check(name, hookmask, e, m->data, m->match_size) != 0) { | |
358 | BUGPRINT("match->check failed\n"); | |
359 | module_put(match->me); | |
360 | return -EINVAL; | |
361 | } | |
362 | (*cnt)++; | |
363 | return 0; | |
364 | } | |
365 | ||
366 | static inline int | |
367 | ebt_check_watcher(struct ebt_entry_watcher *w, struct ebt_entry *e, | |
368 | const char *name, unsigned int hookmask, unsigned int *cnt) | |
369 | { | |
370 | struct ebt_watcher *watcher; | |
14197d54 | 371 | size_t left = ((char *)e + e->target_offset) - (char *)w; |
1da177e4 LT |
372 | int ret; |
373 | ||
14197d54 AV |
374 | if (left < sizeof(struct ebt_entry_watcher) || |
375 | left - sizeof(struct ebt_entry_watcher) < w->watcher_size) | |
1da177e4 LT |
376 | return -EINVAL; |
377 | watcher = find_watcher_lock(w->u.name, &ret, &ebt_mutex); | |
378 | if (!watcher) | |
379 | return ret; | |
380 | w->u.watcher = watcher; | |
381 | if (!try_module_get(watcher->me)) { | |
57b47a53 | 382 | mutex_unlock(&ebt_mutex); |
1da177e4 LT |
383 | return -ENOENT; |
384 | } | |
57b47a53 | 385 | mutex_unlock(&ebt_mutex); |
1da177e4 LT |
386 | if (watcher->check && |
387 | watcher->check(name, hookmask, e, w->data, w->watcher_size) != 0) { | |
388 | BUGPRINT("watcher->check failed\n"); | |
389 | module_put(watcher->me); | |
390 | return -EINVAL; | |
391 | } | |
392 | (*cnt)++; | |
393 | return 0; | |
394 | } | |
395 | ||
70fe9af4 AV |
396 | static int ebt_verify_pointers(struct ebt_replace *repl, |
397 | struct ebt_table_info *newinfo) | |
1da177e4 | 398 | { |
70fe9af4 AV |
399 | unsigned int limit = repl->entries_size; |
400 | unsigned int valid_hooks = repl->valid_hooks; | |
401 | unsigned int offset = 0; | |
1da177e4 LT |
402 | int i; |
403 | ||
e4fd77de AV |
404 | for (i = 0; i < NF_BR_NUMHOOKS; i++) |
405 | newinfo->hook_entry[i] = NULL; | |
406 | ||
407 | newinfo->entries_size = repl->entries_size; | |
408 | newinfo->nentries = repl->nentries; | |
409 | ||
70fe9af4 AV |
410 | while (offset < limit) { |
411 | size_t left = limit - offset; | |
412 | struct ebt_entry *e = (void *)newinfo->entries + offset; | |
bb2ef25c | 413 | |
70fe9af4 | 414 | if (left < sizeof(unsigned int)) |
1da177e4 | 415 | break; |
70fe9af4 AV |
416 | |
417 | for (i = 0; i < NF_BR_NUMHOOKS; i++) { | |
418 | if ((valid_hooks & (1 << i)) == 0) | |
419 | continue; | |
420 | if ((char *)repl->hook_entry[i] == repl->entries + offset) | |
421 | break; | |
422 | } | |
423 | ||
424 | if (i != NF_BR_NUMHOOKS || !(e->bitmask & EBT_ENTRY_OR_ENTRIES)) { | |
425 | if (e->bitmask != 0) { | |
426 | /* we make userspace set this right, | |
427 | so there is no misunderstanding */ | |
428 | BUGPRINT("EBT_ENTRY_OR_ENTRIES shouldn't be set " | |
429 | "in distinguisher\n"); | |
430 | return -EINVAL; | |
431 | } | |
432 | if (i != NF_BR_NUMHOOKS) | |
433 | newinfo->hook_entry[i] = (struct ebt_entries *)e; | |
434 | if (left < sizeof(struct ebt_entries)) | |
435 | break; | |
436 | offset += sizeof(struct ebt_entries); | |
437 | } else { | |
438 | if (left < sizeof(struct ebt_entry)) | |
439 | break; | |
440 | if (left < e->next_offset) | |
441 | break; | |
442 | offset += e->next_offset; | |
1da177e4 | 443 | } |
22b440bf | 444 | } |
70fe9af4 AV |
445 | if (offset != limit) { |
446 | BUGPRINT("entries_size too small\n"); | |
447 | return -EINVAL; | |
448 | } | |
e4fd77de AV |
449 | |
450 | /* check if all valid hooks have a chain */ | |
451 | for (i = 0; i < NF_BR_NUMHOOKS; i++) { | |
452 | if (!newinfo->hook_entry[i] && | |
453 | (valid_hooks & (1 << i))) { | |
454 | BUGPRINT("Valid hook without chain\n"); | |
455 | return -EINVAL; | |
456 | } | |
457 | } | |
22b440bf | 458 | return 0; |
22b440bf AV |
459 | } |
460 | ||
461 | /* | |
462 | * this one is very careful, as it is the first function | |
463 | * to parse the userspace data | |
464 | */ | |
465 | static inline int | |
466 | ebt_check_entry_size_and_hooks(struct ebt_entry *e, | |
0e795531 AV |
467 | struct ebt_table_info *newinfo, |
468 | unsigned int *n, unsigned int *cnt, | |
469 | unsigned int *totalcnt, unsigned int *udc_cnt) | |
22b440bf | 470 | { |
22b440bf AV |
471 | int i; |
472 | ||
473 | for (i = 0; i < NF_BR_NUMHOOKS; i++) { | |
0e795531 | 474 | if ((void *)e == (void *)newinfo->hook_entry[i]) |
22b440bf AV |
475 | break; |
476 | } | |
477 | /* beginning of a new chain | |
478 | if i == NF_BR_NUMHOOKS it must be a user defined chain */ | |
479 | if (i != NF_BR_NUMHOOKS || !e->bitmask) { | |
1da177e4 LT |
480 | /* this checks if the previous chain has as many entries |
481 | as it said it has */ | |
482 | if (*n != *cnt) { | |
483 | BUGPRINT("nentries does not equal the nr of entries " | |
484 | "in the chain\n"); | |
485 | return -EINVAL; | |
486 | } | |
1da177e4 LT |
487 | if (((struct ebt_entries *)e)->policy != EBT_DROP && |
488 | ((struct ebt_entries *)e)->policy != EBT_ACCEPT) { | |
489 | /* only RETURN from udc */ | |
490 | if (i != NF_BR_NUMHOOKS || | |
491 | ((struct ebt_entries *)e)->policy != EBT_RETURN) { | |
492 | BUGPRINT("bad policy\n"); | |
493 | return -EINVAL; | |
494 | } | |
495 | } | |
496 | if (i == NF_BR_NUMHOOKS) /* it's a user defined chain */ | |
497 | (*udc_cnt)++; | |
1da177e4 LT |
498 | if (((struct ebt_entries *)e)->counter_offset != *totalcnt) { |
499 | BUGPRINT("counter_offset != totalcnt"); | |
500 | return -EINVAL; | |
501 | } | |
502 | *n = ((struct ebt_entries *)e)->nentries; | |
503 | *cnt = 0; | |
504 | return 0; | |
505 | } | |
506 | /* a plain old entry, heh */ | |
507 | if (sizeof(struct ebt_entry) > e->watchers_offset || | |
508 | e->watchers_offset > e->target_offset || | |
509 | e->target_offset >= e->next_offset) { | |
510 | BUGPRINT("entry offsets not in right order\n"); | |
511 | return -EINVAL; | |
512 | } | |
513 | /* this is not checked anywhere else */ | |
514 | if (e->next_offset - e->target_offset < sizeof(struct ebt_entry_target)) { | |
515 | BUGPRINT("target size too small\n"); | |
516 | return -EINVAL; | |
517 | } | |
1da177e4 LT |
518 | (*cnt)++; |
519 | (*totalcnt)++; | |
520 | return 0; | |
521 | } | |
522 | ||
523 | struct ebt_cl_stack | |
524 | { | |
525 | struct ebt_chainstack cs; | |
526 | int from; | |
527 | unsigned int hookmask; | |
528 | }; | |
529 | ||
530 | /* | |
531 | * we need these positions to check that the jumps to a different part of the | |
532 | * entries is a jump to the beginning of a new chain. | |
533 | */ | |
534 | static inline int | |
535 | ebt_get_udc_positions(struct ebt_entry *e, struct ebt_table_info *newinfo, | |
177abc34 | 536 | unsigned int *n, struct ebt_cl_stack *udc) |
1da177e4 LT |
537 | { |
538 | int i; | |
539 | ||
540 | /* we're only interested in chain starts */ | |
40642f95 | 541 | if (e->bitmask) |
1da177e4 LT |
542 | return 0; |
543 | for (i = 0; i < NF_BR_NUMHOOKS; i++) { | |
1da177e4 LT |
544 | if (newinfo->hook_entry[i] == (struct ebt_entries *)e) |
545 | break; | |
546 | } | |
547 | /* only care about udc */ | |
548 | if (i != NF_BR_NUMHOOKS) | |
549 | return 0; | |
550 | ||
551 | udc[*n].cs.chaininfo = (struct ebt_entries *)e; | |
552 | /* these initialisations are depended on later in check_chainloops() */ | |
553 | udc[*n].cs.n = 0; | |
554 | udc[*n].hookmask = 0; | |
555 | ||
556 | (*n)++; | |
557 | return 0; | |
558 | } | |
559 | ||
560 | static inline int | |
561 | ebt_cleanup_match(struct ebt_entry_match *m, unsigned int *i) | |
562 | { | |
563 | if (i && (*i)-- == 0) | |
564 | return 1; | |
565 | if (m->u.match->destroy) | |
566 | m->u.match->destroy(m->data, m->match_size); | |
567 | module_put(m->u.match->me); | |
568 | ||
569 | return 0; | |
570 | } | |
571 | ||
572 | static inline int | |
573 | ebt_cleanup_watcher(struct ebt_entry_watcher *w, unsigned int *i) | |
574 | { | |
575 | if (i && (*i)-- == 0) | |
576 | return 1; | |
577 | if (w->u.watcher->destroy) | |
578 | w->u.watcher->destroy(w->data, w->watcher_size); | |
579 | module_put(w->u.watcher->me); | |
580 | ||
581 | return 0; | |
582 | } | |
583 | ||
584 | static inline int | |
585 | ebt_cleanup_entry(struct ebt_entry *e, unsigned int *cnt) | |
586 | { | |
587 | struct ebt_entry_target *t; | |
588 | ||
40642f95 | 589 | if (e->bitmask == 0) |
1da177e4 LT |
590 | return 0; |
591 | /* we're done */ | |
592 | if (cnt && (*cnt)-- == 0) | |
593 | return 1; | |
594 | EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, NULL); | |
595 | EBT_MATCH_ITERATE(e, ebt_cleanup_match, NULL); | |
596 | t = (struct ebt_entry_target *)(((char *)e) + e->target_offset); | |
597 | if (t->u.target->destroy) | |
598 | t->u.target->destroy(t->data, t->target_size); | |
599 | module_put(t->u.target->me); | |
600 | ||
601 | return 0; | |
602 | } | |
603 | ||
604 | static inline int | |
605 | ebt_check_entry(struct ebt_entry *e, struct ebt_table_info *newinfo, | |
f7da79d9 | 606 | const char *name, unsigned int *cnt, |
1da177e4 LT |
607 | struct ebt_cl_stack *cl_s, unsigned int udc_cnt) |
608 | { | |
609 | struct ebt_entry_target *t; | |
610 | struct ebt_target *target; | |
611 | unsigned int i, j, hook = 0, hookmask = 0; | |
14197d54 | 612 | size_t gap = e->next_offset - e->target_offset; |
1da177e4 LT |
613 | int ret; |
614 | ||
615 | /* don't mess with the struct ebt_entries */ | |
40642f95 | 616 | if (e->bitmask == 0) |
1da177e4 LT |
617 | return 0; |
618 | ||
619 | if (e->bitmask & ~EBT_F_MASK) { | |
620 | BUGPRINT("Unknown flag for bitmask\n"); | |
621 | return -EINVAL; | |
622 | } | |
623 | if (e->invflags & ~EBT_INV_MASK) { | |
624 | BUGPRINT("Unknown flag for inv bitmask\n"); | |
625 | return -EINVAL; | |
626 | } | |
627 | if ( (e->bitmask & EBT_NOPROTO) && (e->bitmask & EBT_802_3) ) { | |
628 | BUGPRINT("NOPROTO & 802_3 not allowed\n"); | |
629 | return -EINVAL; | |
630 | } | |
631 | /* what hook do we belong to? */ | |
632 | for (i = 0; i < NF_BR_NUMHOOKS; i++) { | |
f7da79d9 | 633 | if (!newinfo->hook_entry[i]) |
1da177e4 LT |
634 | continue; |
635 | if ((char *)newinfo->hook_entry[i] < (char *)e) | |
636 | hook = i; | |
637 | else | |
638 | break; | |
639 | } | |
640 | /* (1 << NF_BR_NUMHOOKS) tells the check functions the rule is on | |
641 | a base chain */ | |
642 | if (i < NF_BR_NUMHOOKS) | |
643 | hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS); | |
644 | else { | |
645 | for (i = 0; i < udc_cnt; i++) | |
646 | if ((char *)(cl_s[i].cs.chaininfo) > (char *)e) | |
647 | break; | |
648 | if (i == 0) | |
649 | hookmask = (1 << hook) | (1 << NF_BR_NUMHOOKS); | |
650 | else | |
651 | hookmask = cl_s[i - 1].hookmask; | |
652 | } | |
653 | i = 0; | |
654 | ret = EBT_MATCH_ITERATE(e, ebt_check_match, e, name, hookmask, &i); | |
655 | if (ret != 0) | |
656 | goto cleanup_matches; | |
657 | j = 0; | |
658 | ret = EBT_WATCHER_ITERATE(e, ebt_check_watcher, e, name, hookmask, &j); | |
659 | if (ret != 0) | |
660 | goto cleanup_watchers; | |
661 | t = (struct ebt_entry_target *)(((char *)e) + e->target_offset); | |
662 | target = find_target_lock(t->u.name, &ret, &ebt_mutex); | |
663 | if (!target) | |
664 | goto cleanup_watchers; | |
665 | if (!try_module_get(target->me)) { | |
57b47a53 | 666 | mutex_unlock(&ebt_mutex); |
1da177e4 LT |
667 | ret = -ENOENT; |
668 | goto cleanup_watchers; | |
669 | } | |
57b47a53 | 670 | mutex_unlock(&ebt_mutex); |
1da177e4 LT |
671 | |
672 | t->u.target = target; | |
673 | if (t->u.target == &ebt_standard_target) { | |
14197d54 | 674 | if (gap < sizeof(struct ebt_standard_target)) { |
1da177e4 LT |
675 | BUGPRINT("Standard target size too big\n"); |
676 | ret = -EFAULT; | |
677 | goto cleanup_watchers; | |
678 | } | |
679 | if (((struct ebt_standard_target *)t)->verdict < | |
680 | -NUM_STANDARD_TARGETS) { | |
681 | BUGPRINT("Invalid standard target\n"); | |
682 | ret = -EFAULT; | |
683 | goto cleanup_watchers; | |
684 | } | |
14197d54 | 685 | } else if (t->target_size > gap - sizeof(struct ebt_entry_target) || |
1da177e4 LT |
686 | (t->u.target->check && |
687 | t->u.target->check(name, hookmask, e, t->data, t->target_size) != 0)){ | |
688 | module_put(t->u.target->me); | |
689 | ret = -EFAULT; | |
690 | goto cleanup_watchers; | |
691 | } | |
692 | (*cnt)++; | |
693 | return 0; | |
694 | cleanup_watchers: | |
695 | EBT_WATCHER_ITERATE(e, ebt_cleanup_watcher, &j); | |
696 | cleanup_matches: | |
697 | EBT_MATCH_ITERATE(e, ebt_cleanup_match, &i); | |
698 | return ret; | |
699 | } | |
700 | ||
701 | /* | |
702 | * checks for loops and sets the hook mask for udc | |
703 | * the hook mask for udc tells us from which base chains the udc can be | |
704 | * accessed. This mask is a parameter to the check() functions of the extensions | |
705 | */ | |
706 | static int check_chainloops(struct ebt_entries *chain, struct ebt_cl_stack *cl_s, | |
707 | unsigned int udc_cnt, unsigned int hooknr, char *base) | |
708 | { | |
709 | int i, chain_nr = -1, pos = 0, nentries = chain->nentries, verdict; | |
710 | struct ebt_entry *e = (struct ebt_entry *)chain->data; | |
711 | struct ebt_entry_target *t; | |
712 | ||
713 | while (pos < nentries || chain_nr != -1) { | |
714 | /* end of udc, go back one 'recursion' step */ | |
715 | if (pos == nentries) { | |
716 | /* put back values of the time when this chain was called */ | |
717 | e = cl_s[chain_nr].cs.e; | |
718 | if (cl_s[chain_nr].from != -1) | |
719 | nentries = | |
720 | cl_s[cl_s[chain_nr].from].cs.chaininfo->nentries; | |
721 | else | |
722 | nentries = chain->nentries; | |
723 | pos = cl_s[chain_nr].cs.n; | |
724 | /* make sure we won't see a loop that isn't one */ | |
725 | cl_s[chain_nr].cs.n = 0; | |
726 | chain_nr = cl_s[chain_nr].from; | |
727 | if (pos == nentries) | |
728 | continue; | |
729 | } | |
730 | t = (struct ebt_entry_target *) | |
731 | (((char *)e) + e->target_offset); | |
732 | if (strcmp(t->u.name, EBT_STANDARD_TARGET)) | |
733 | goto letscontinue; | |
734 | if (e->target_offset + sizeof(struct ebt_standard_target) > | |
735 | e->next_offset) { | |
736 | BUGPRINT("Standard target size too big\n"); | |
737 | return -1; | |
738 | } | |
739 | verdict = ((struct ebt_standard_target *)t)->verdict; | |
740 | if (verdict >= 0) { /* jump to another chain */ | |
741 | struct ebt_entries *hlp2 = | |
742 | (struct ebt_entries *)(base + verdict); | |
743 | for (i = 0; i < udc_cnt; i++) | |
744 | if (hlp2 == cl_s[i].cs.chaininfo) | |
745 | break; | |
746 | /* bad destination or loop */ | |
747 | if (i == udc_cnt) { | |
748 | BUGPRINT("bad destination\n"); | |
749 | return -1; | |
750 | } | |
751 | if (cl_s[i].cs.n) { | |
752 | BUGPRINT("loop\n"); | |
753 | return -1; | |
754 | } | |
98a0824a AV |
755 | if (cl_s[i].hookmask & (1 << hooknr)) |
756 | goto letscontinue; | |
757 | /* this can't be 0, so the loop test is correct */ | |
1da177e4 LT |
758 | cl_s[i].cs.n = pos + 1; |
759 | pos = 0; | |
760 | cl_s[i].cs.e = ((void *)e + e->next_offset); | |
761 | e = (struct ebt_entry *)(hlp2->data); | |
762 | nentries = hlp2->nentries; | |
763 | cl_s[i].from = chain_nr; | |
764 | chain_nr = i; | |
765 | /* this udc is accessible from the base chain for hooknr */ | |
766 | cl_s[i].hookmask |= (1 << hooknr); | |
767 | continue; | |
768 | } | |
769 | letscontinue: | |
770 | e = (void *)e + e->next_offset; | |
771 | pos++; | |
772 | } | |
773 | return 0; | |
774 | } | |
775 | ||
776 | /* do the parsing of the table/chains/entries/matches/watchers/targets, heh */ | |
1bc2326c | 777 | static int translate_table(char *name, struct ebt_table_info *newinfo) |
1da177e4 LT |
778 | { |
779 | unsigned int i, j, k, udc_cnt; | |
780 | int ret; | |
781 | struct ebt_cl_stack *cl_s = NULL; /* used in the checking for chain loops */ | |
782 | ||
783 | i = 0; | |
1f072c96 | 784 | while (i < NF_BR_NUMHOOKS && !newinfo->hook_entry[i]) |
1da177e4 LT |
785 | i++; |
786 | if (i == NF_BR_NUMHOOKS) { | |
787 | BUGPRINT("No valid hooks specified\n"); | |
788 | return -EINVAL; | |
789 | } | |
1f072c96 | 790 | if (newinfo->hook_entry[i] != (struct ebt_entries *)newinfo->entries) { |
1da177e4 LT |
791 | BUGPRINT("Chains don't start at beginning\n"); |
792 | return -EINVAL; | |
793 | } | |
794 | /* make sure chains are ordered after each other in same order | |
795 | as their corresponding hooks */ | |
796 | for (j = i + 1; j < NF_BR_NUMHOOKS; j++) { | |
1f072c96 | 797 | if (!newinfo->hook_entry[j]) |
1da177e4 | 798 | continue; |
1f072c96 | 799 | if (newinfo->hook_entry[j] <= newinfo->hook_entry[i]) { |
1da177e4 LT |
800 | BUGPRINT("Hook order must be followed\n"); |
801 | return -EINVAL; | |
802 | } | |
803 | i = j; | |
804 | } | |
805 | ||
1da177e4 LT |
806 | /* do some early checkings and initialize some things */ |
807 | i = 0; /* holds the expected nr. of entries for the chain */ | |
808 | j = 0; /* holds the up to now counted entries for the chain */ | |
809 | k = 0; /* holds the total nr. of entries, should equal | |
810 | newinfo->nentries afterwards */ | |
811 | udc_cnt = 0; /* will hold the nr. of user defined chains (udc) */ | |
812 | ret = EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size, | |
0e795531 AV |
813 | ebt_check_entry_size_and_hooks, newinfo, |
814 | &i, &j, &k, &udc_cnt); | |
1da177e4 LT |
815 | |
816 | if (ret != 0) | |
817 | return ret; | |
818 | ||
819 | if (i != j) { | |
820 | BUGPRINT("nentries does not equal the nr of entries in the " | |
821 | "(last) chain\n"); | |
822 | return -EINVAL; | |
823 | } | |
824 | if (k != newinfo->nentries) { | |
825 | BUGPRINT("Total nentries is wrong\n"); | |
826 | return -EINVAL; | |
827 | } | |
828 | ||
1da177e4 LT |
829 | /* get the location of the udc, put them in an array |
830 | while we're at it, allocate the chainstack */ | |
831 | if (udc_cnt) { | |
832 | /* this will get free'd in do_replace()/ebt_register_table() | |
833 | if an error occurs */ | |
7ad4d2f6 J |
834 | newinfo->chainstack = |
835 | vmalloc((highest_possible_processor_id()+1) | |
836 | * sizeof(*(newinfo->chainstack))); | |
1da177e4 LT |
837 | if (!newinfo->chainstack) |
838 | return -ENOMEM; | |
6f912042 | 839 | for_each_possible_cpu(i) { |
1da177e4 | 840 | newinfo->chainstack[i] = |
18bc89aa | 841 | vmalloc(udc_cnt * sizeof(*(newinfo->chainstack[0]))); |
1da177e4 LT |
842 | if (!newinfo->chainstack[i]) { |
843 | while (i) | |
844 | vfree(newinfo->chainstack[--i]); | |
845 | vfree(newinfo->chainstack); | |
846 | newinfo->chainstack = NULL; | |
847 | return -ENOMEM; | |
848 | } | |
849 | } | |
850 | ||
18bc89aa | 851 | cl_s = vmalloc(udc_cnt * sizeof(*cl_s)); |
1da177e4 LT |
852 | if (!cl_s) |
853 | return -ENOMEM; | |
854 | i = 0; /* the i'th udc */ | |
855 | EBT_ENTRY_ITERATE(newinfo->entries, newinfo->entries_size, | |
177abc34 | 856 | ebt_get_udc_positions, newinfo, &i, cl_s); |
1da177e4 LT |
857 | /* sanity check */ |
858 | if (i != udc_cnt) { | |
859 | BUGPRINT("i != udc_cnt\n"); | |
860 | vfree(cl_s); | |
861 | return -EFAULT; | |
862 | } | |
863 | } | |
864 | ||
865 | /* Check for loops */ | |
866 | for (i = 0; i < NF_BR_NUMHOOKS; i++) | |
1f072c96 | 867 | if (newinfo->hook_entry[i]) |
1da177e4 LT |
868 | if (check_chainloops(newinfo->hook_entry[i], |
869 | cl_s, udc_cnt, i, newinfo->entries)) { | |
68d31872 | 870 | vfree(cl_s); |
1da177e4 LT |
871 | return -EINVAL; |
872 | } | |
873 | ||
874 |