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d15c345f PM |
1 | /* |
2 | * NetLabel Domain Hash Table | |
3 | * | |
4 | * This file manages the domain hash table that NetLabel uses to determine | |
5 | * which network labeling protocol to use for a given domain. The NetLabel | |
6 | * system manages static and dynamic label mappings for network protocols such | |
7 | * as CIPSO and RIPSO. | |
8 | * | |
9 | * Author: Paul Moore <paul.moore@hp.com> | |
10 | * | |
11 | */ | |
12 | ||
13 | /* | |
14 | * (c) Copyright Hewlett-Packard Development Company, L.P., 2006 | |
15 | * | |
16 | * This program is free software; you can redistribute it and/or modify | |
17 | * it under the terms of the GNU General Public License as published by | |
18 | * the Free Software Foundation; either version 2 of the License, or | |
19 | * (at your option) any later version. | |
20 | * | |
21 | * This program is distributed in the hope that it will be useful, | |
22 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
23 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See | |
24 | * the GNU General Public License for more details. | |
25 | * | |
26 | * You should have received a copy of the GNU General Public License | |
27 | * along with this program; if not, write to the Free Software | |
28 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
29 | * | |
30 | */ | |
31 | ||
32 | #include <linux/types.h> | |
33 | #include <linux/rcupdate.h> | |
34 | #include <linux/list.h> | |
35 | #include <linux/skbuff.h> | |
36 | #include <linux/spinlock.h> | |
37 | #include <linux/string.h> | |
32f50cde | 38 | #include <linux/audit.h> |
d15c345f PM |
39 | #include <net/netlabel.h> |
40 | #include <net/cipso_ipv4.h> | |
41 | #include <asm/bug.h> | |
42 | ||
43 | #include "netlabel_mgmt.h" | |
44 | #include "netlabel_domainhash.h" | |
32f50cde | 45 | #include "netlabel_user.h" |
d15c345f PM |
46 | |
47 | struct netlbl_domhsh_tbl { | |
48 | struct list_head *tbl; | |
49 | u32 size; | |
50 | }; | |
51 | ||
52 | /* Domain hash table */ | |
53 | /* XXX - updates should be so rare that having one spinlock for the entire | |
54 | * hash table should be okay */ | |
8ce11e6a | 55 | static DEFINE_SPINLOCK(netlbl_domhsh_lock); |
d15c345f PM |
56 | static struct netlbl_domhsh_tbl *netlbl_domhsh = NULL; |
57 | ||
58 | /* Default domain mapping */ | |
8ce11e6a | 59 | static DEFINE_SPINLOCK(netlbl_domhsh_def_lock); |
d15c345f PM |
60 | static struct netlbl_dom_map *netlbl_domhsh_def = NULL; |
61 | ||
62 | /* | |
63 | * Domain Hash Table Helper Functions | |
64 | */ | |
65 | ||
66 | /** | |
67 | * netlbl_domhsh_free_entry - Frees a domain hash table entry | |
68 | * @entry: the entry's RCU field | |
69 | * | |
70 | * Description: | |
71 | * This function is designed to be used as a callback to the call_rcu() | |
72 | * function so that the memory allocated to a hash table entry can be released | |
73 | * safely. | |
74 | * | |
75 | */ | |
76 | static void netlbl_domhsh_free_entry(struct rcu_head *entry) | |
77 | { | |
78 | struct netlbl_dom_map *ptr; | |
79 | ||
80 | ptr = container_of(entry, struct netlbl_dom_map, rcu); | |
81 | kfree(ptr->domain); | |
82 | kfree(ptr); | |
83 | } | |
84 | ||
85 | /** | |
86 | * netlbl_domhsh_hash - Hashing function for the domain hash table | |
87 | * @domain: the domain name to hash | |
88 | * | |
89 | * Description: | |
90 | * This is the hashing function for the domain hash table, it returns the | |
91 | * correct bucket number for the domain. The caller is responsibile for | |
92 | * calling the rcu_read_[un]lock() functions. | |
93 | * | |
94 | */ | |
95 | static u32 netlbl_domhsh_hash(const char *key) | |
96 | { | |
97 | u32 iter; | |
98 | u32 val; | |
99 | u32 len; | |
100 | ||
101 | /* This is taken (with slight modification) from | |
102 | * security/selinux/ss/symtab.c:symhash() */ | |
103 | ||
104 | for (iter = 0, val = 0, len = strlen(key); iter < len; iter++) | |
105 | val = (val << 4 | (val >> (8 * sizeof(u32) - 4))) ^ key[iter]; | |
106 | return val & (rcu_dereference(netlbl_domhsh)->size - 1); | |
107 | } | |
108 | ||
109 | /** | |
110 | * netlbl_domhsh_search - Search for a domain entry | |
111 | * @domain: the domain | |
112 | * @def: return default if no match is found | |
113 | * | |
114 | * Description: | |
115 | * Searches the domain hash table and returns a pointer to the hash table | |
116 | * entry if found, otherwise NULL is returned. If @def is non-zero and a | |
117 | * match is not found in the domain hash table the default mapping is returned | |
118 | * if it exists. The caller is responsibile for the rcu hash table locks | |
119 | * (i.e. the caller much call rcu_read_[un]lock()). | |
120 | * | |
121 | */ | |
122 | static struct netlbl_dom_map *netlbl_domhsh_search(const char *domain, u32 def) | |
123 | { | |
124 | u32 bkt; | |
125 | struct netlbl_dom_map *iter; | |
126 | ||
127 | if (domain != NULL) { | |
128 | bkt = netlbl_domhsh_hash(domain); | |
129 | list_for_each_entry_rcu(iter, &netlbl_domhsh->tbl[bkt], list) | |
130 | if (iter->valid && strcmp(iter->domain, domain) == 0) | |
131 | return iter; | |
132 | } | |
133 | ||
134 | if (def != 0) { | |
135 | iter = rcu_dereference(netlbl_domhsh_def); | |
136 | if (iter != NULL && iter->valid) | |
137 | return iter; | |
138 | } | |
139 | ||
140 | return NULL; | |
141 | } | |
142 | ||
143 | /* | |
144 | * Domain Hash Table Functions | |
145 | */ | |
146 | ||
147 | /** | |
148 | * netlbl_domhsh_init - Init for the domain hash | |
149 | * @size: the number of bits to use for the hash buckets | |
150 | * | |
151 | * Description: | |
152 | * Initializes the domain hash table, should be called only by | |
153 | * netlbl_user_init() during initialization. Returns zero on success, non-zero | |
154 | * values on error. | |
155 | * | |
156 | */ | |
157 | int netlbl_domhsh_init(u32 size) | |
158 | { | |
159 | u32 iter; | |
160 | struct netlbl_domhsh_tbl *hsh_tbl; | |
161 | ||
162 | if (size == 0) | |
163 | return -EINVAL; | |
164 | ||
165 | hsh_tbl = kmalloc(sizeof(*hsh_tbl), GFP_KERNEL); | |
166 | if (hsh_tbl == NULL) | |
167 | return -ENOMEM; | |
168 | hsh_tbl->size = 1 << size; | |
169 | hsh_tbl->tbl = kcalloc(hsh_tbl->size, | |
170 | sizeof(struct list_head), | |
171 | GFP_KERNEL); | |
172 | if (hsh_tbl->tbl == NULL) { | |
173 | kfree(hsh_tbl); | |
174 | return -ENOMEM; | |
175 | } | |
176 | for (iter = 0; iter < hsh_tbl->size; iter++) | |
177 | INIT_LIST_HEAD(&hsh_tbl->tbl[iter]); | |
178 | ||
179 | rcu_read_lock(); | |
180 | spin_lock(&netlbl_domhsh_lock); | |
181 | rcu_assign_pointer(netlbl_domhsh, hsh_tbl); | |
182 | spin_unlock(&netlbl_domhsh_lock); | |
183 | rcu_read_unlock(); | |
184 | ||
185 | return 0; | |
186 | } | |
187 | ||
188 | /** | |
189 | * netlbl_domhsh_add - Adds a entry to the domain hash table | |
190 | * @entry: the entry to add | |
95d4e6be | 191 | * @audit_info: NetLabel audit information |
d15c345f PM |
192 | * |
193 | * Description: | |
194 | * Adds a new entry to the domain hash table and handles any updates to the | |
195 | * lower level protocol handler (i.e. CIPSO). Returns zero on success, | |
196 | * negative on failure. | |
197 | * | |
198 | */ | |
95d4e6be PM |
199 | int netlbl_domhsh_add(struct netlbl_dom_map *entry, |
200 | struct netlbl_audit *audit_info) | |
d15c345f PM |
201 | { |
202 | int ret_val; | |
203 | u32 bkt; | |
32f50cde PM |
204 | struct audit_buffer *audit_buf; |
205 | char *audit_domain; | |
d15c345f PM |
206 | |
207 | switch (entry->type) { | |
208 | case NETLBL_NLTYPE_UNLABELED: | |
209 | ret_val = 0; | |
210 | break; | |
211 | case NETLBL_NLTYPE_CIPSOV4: | |
212 | ret_val = cipso_v4_doi_domhsh_add(entry->type_def.cipsov4, | |
213 | entry->domain); | |
214 | break; | |
215 | default: | |
216 | return -EINVAL; | |
217 | } | |
218 | if (ret_val != 0) | |
219 | return ret_val; | |
220 | ||
221 | entry->valid = 1; | |
222 | INIT_RCU_HEAD(&entry->rcu); | |
223 | ||
224 | ret_val = 0; | |
225 | rcu_read_lock(); | |
226 | if (entry->domain != NULL) { | |
227 | bkt = netlbl_domhsh_hash(entry->domain); | |
228 | spin_lock(&netlbl_domhsh_lock); | |
229 | if (netlbl_domhsh_search(entry->domain, 0) == NULL) | |
230 | list_add_tail_rcu(&entry->list, | |
231 | &netlbl_domhsh->tbl[bkt]); | |
232 | else | |
233 | ret_val = -EEXIST; | |
234 | spin_unlock(&netlbl_domhsh_lock); | |
235 | } else if (entry->domain == NULL) { | |
236 | INIT_LIST_HEAD(&entry->list); | |
237 | spin_lock(&netlbl_domhsh_def_lock); | |
238 | if (rcu_dereference(netlbl_domhsh_def) == NULL) | |
239 | rcu_assign_pointer(netlbl_domhsh_def, entry); | |
240 | else | |
241 | ret_val = -EEXIST; | |
242 | spin_unlock(&netlbl_domhsh_def_lock); | |
243 | } else | |
244 | ret_val = -EINVAL; | |
95d4e6be PM |
245 | |
246 | if (entry->domain != NULL) | |
247 | audit_domain = entry->domain; | |
248 | else | |
249 | audit_domain = "(default)"; | |
250 | audit_buf = netlbl_audit_start_common(AUDIT_MAC_MAP_ADD, audit_info); | |
251 | audit_log_format(audit_buf, " nlbl_domain=%s", audit_domain); | |
252 | switch (entry->type) { | |
253 | case NETLBL_NLTYPE_UNLABELED: | |
254 | audit_log_format(audit_buf, " nlbl_protocol=unlbl"); | |
255 | break; | |
256 | case NETLBL_NLTYPE_CIPSOV4: | |
257 | audit_log_format(audit_buf, | |
258 | " nlbl_protocol=cipsov4 cipso_doi=%u", | |
259 | entry->type_def.cipsov4->doi); | |
260 | break; | |
32f50cde | 261 | } |
95d4e6be PM |
262 | audit_log_format(audit_buf, " res=%u", ret_val == 0 ? 1 : 0); |
263 | audit_log_end(audit_buf); | |
264 | ||
d15c345f PM |
265 | rcu_read_unlock(); |
266 | ||
267 | if (ret_val != 0) { | |
268 | switch (entry->type) { | |
269 | case NETLBL_NLTYPE_CIPSOV4: | |
270 | if (cipso_v4_doi_domhsh_remove(entry->type_def.cipsov4, | |
271 | entry->domain) != 0) | |
272 | BUG(); | |
273 | break; | |
274 | } | |
275 | } | |
276 | ||
277 | return ret_val; | |
278 | } | |
279 | ||
280 | /** | |
281 | * netlbl_domhsh_add_default - Adds the default entry to the domain hash table | |
282 | * @entry: the entry to add | |
95d4e6be | 283 | * @audit_info: NetLabel audit information |
d15c345f PM |
284 | * |
285 | * Description: | |
286 | * Adds a new default entry to the domain hash table and handles any updates | |
287 | * to the lower level protocol handler (i.e. CIPSO). Returns zero on success, | |
288 | * negative on failure. | |
289 | * | |
290 | */ | |
95d4e6be PM |
291 | int netlbl_domhsh_add_default(struct netlbl_dom_map *entry, |
292 | struct netlbl_audit *audit_info) | |
d15c345f | 293 | { |
95d4e6be | 294 | return netlbl_domhsh_add(entry, audit_info); |
d15c345f PM |
295 | } |
296 | ||
297 | /** | |
298 | * netlbl_domhsh_remove - Removes an entry from the domain hash table | |
299 | * @domain: the domain to remove | |
95d4e6be | 300 | * @audit_info: NetLabel audit information |
d15c345f PM |
301 | * |
302 | * Description: | |
303 | * Removes an entry from the domain hash table and handles any updates to the | |
304 | * lower level protocol handler (i.e. CIPSO). Returns zero on success, | |
305 | * negative on failure. | |
306 | * | |
307 | */ | |
95d4e6be | 308 | int netlbl_domhsh_remove(const char *domain, struct netlbl_audit *audit_info) |
d15c345f PM |
309 | { |
310 | int ret_val = -ENOENT; | |
311 | struct netlbl_dom_map *entry; | |
32f50cde PM |
312 | struct audit_buffer *audit_buf; |
313 | char *audit_domain; | |
d15c345f PM |
314 | |
315 | rcu_read_lock(); | |
316 | if (domain != NULL) | |
317 | entry = netlbl_domhsh_search(domain, 0); | |
318 | else | |
319 | entry = netlbl_domhsh_search(domain, 1); | |
320 | if (entry == NULL) | |
321 | goto remove_return; | |
322 | switch (entry->type) { | |
323 | case NETLBL_NLTYPE_UNLABELED: | |
324 | break; | |
325 | case NETLBL_NLTYPE_CIPSOV4: | |
326 | ret_val = cipso_v4_doi_domhsh_remove(entry->type_def.cipsov4, | |
327 | entry->domain); | |
328 | if (ret_val != 0) | |
329 | goto remove_return; | |
330 | break; | |
331 | } | |
332 | ret_val = 0; | |
333 | if (entry != rcu_dereference(netlbl_domhsh_def)) { | |
334 | spin_lock(&netlbl_domhsh_lock); | |
335 | if (entry->valid) { | |
336 | entry->valid = 0; | |
337 | list_del_rcu(&entry->list); | |
338 | } else | |
339 | ret_val = -ENOENT; | |
340 | spin_unlock(&netlbl_domhsh_lock); | |
341 | } else { | |
342 | spin_lock(&netlbl_domhsh_def_lock); | |
343 | if (entry->valid) { | |
344 | entry->valid = 0; | |
345 | rcu_assign_pointer(netlbl_domhsh_def, NULL); | |
346 | } else | |
347 | ret_val = -ENOENT; | |
348 | spin_unlock(&netlbl_domhsh_def_lock); | |
349 | } | |
32f50cde | 350 | |
95d4e6be PM |
351 | if (entry->domain != NULL) |
352 | audit_domain = entry->domain; | |
353 | else | |
354 | audit_domain = "(default)"; | |
355 | audit_buf = netlbl_audit_start_common(AUDIT_MAC_MAP_DEL, audit_info); | |
356 | audit_log_format(audit_buf, | |
357 | " nlbl_domain=%s res=%u", | |
358 | audit_domain, | |
359 | ret_val == 0 ? 1 : 0); | |
360 | audit_log_end(audit_buf); | |
361 | ||
362 | if (ret_val == 0) | |
d15c345f PM |
363 | call_rcu(&entry->rcu, netlbl_domhsh_free_entry); |
364 | ||
365 | remove_return: | |
366 | rcu_read_unlock(); | |
367 | return ret_val; | |
368 | } | |
369 | ||
370 | /** | |
371 | * netlbl_domhsh_remove_default - Removes the default entry from the table | |
95d4e6be | 372 | * @audit_info: NetLabel audit information |
d15c345f PM |
373 | * |
374 | * Description: | |
375 | * Removes/resets the default entry for the domain hash table and handles any | |
376 | * updates to the lower level protocol handler (i.e. CIPSO). Returns zero on | |
377 | * success, non-zero on failure. | |
378 | * | |
379 | */ | |
95d4e6be | 380 | int netlbl_domhsh_remove_default(struct netlbl_audit *audit_info) |
d15c345f | 381 | { |
95d4e6be | 382 | return netlbl_domhsh_remove(NULL, audit_info); |
d15c345f PM |
383 | } |
384 | ||
385 | /** | |
386 | * netlbl_domhsh_getentry - Get an entry from the domain hash table | |
387 | * @domain: the domain name to search for | |
388 | * | |
389 | * Description: | |
390 | * Look through the domain hash table searching for an entry to match @domain, | |
391 | * return a pointer to a copy of the entry or NULL. The caller is responsibile | |
392 | * for ensuring that rcu_read_[un]lock() is called. | |
393 | * | |
394 | */ | |
395 | struct netlbl_dom_map *netlbl_domhsh_getentry(const char *domain) | |
396 | { | |
397 | return netlbl_domhsh_search(domain, 1); | |
398 | } | |
399 | ||
400 | /** | |
fcd48280 PM |
401 | * netlbl_domhsh_walk - Iterate through the domain mapping hash table |
402 | * @skip_bkt: the number of buckets to skip at the start | |
403 | * @skip_chain: the number of entries to skip in the first iterated bucket | |
404 | * @callback: callback for each entry | |
405 | * @cb_arg: argument for the callback function | |
d15c345f PM |
406 | * |
407 | * Description: | |
fcd48280 PM |
408 | * Interate over the domain mapping hash table, skipping the first @skip_bkt |
409 | * buckets and @skip_chain entries. For each entry in the table call | |
410 | * @callback, if @callback returns a negative value stop 'walking' through the | |
411 | * table and return. Updates the values in @skip_bkt and @skip_chain on | |
412 | * return. Returns zero on succcess, negative values on failure. | |
d15c345f PM |
413 | * |
414 | */ | |
fcd48280 PM |
415 | int netlbl_domhsh_walk(u32 *skip_bkt, |
416 | u32 *skip_chain, | |
417 | int (*callback) (struct netlbl_dom_map *entry, void *arg), | |
418 | void *cb_arg) | |
d15c345f | 419 | { |
fcd48280 PM |
420 | int ret_val = -ENOENT; |
421 | u32 iter_bkt; | |
422 | struct netlbl_dom_map *iter_entry; | |
423 | u32 chain_cnt = 0; | |
d15c345f | 424 | |
d15c345f | 425 | rcu_read_lock(); |
fcd48280 PM |
426 | for (iter_bkt = *skip_bkt; |
427 | iter_bkt < rcu_dereference(netlbl_domhsh)->size; | |
428 | iter_bkt++, chain_cnt = 0) { | |
429 | list_for_each_entry_rcu(iter_entry, | |
430 | &netlbl_domhsh->tbl[iter_bkt], | |
431 | list) | |
432 | if (iter_entry->valid) { | |
433 | if (chain_cnt++ < *skip_chain) | |
434 | continue; | |
435 | ret_val = callback(iter_entry, cb_arg); | |
436 | if (ret_val < 0) { | |
437 | chain_cnt--; | |
438 | goto walk_return; | |
439 | } | |
d15c345f | 440 | } |
fcd48280 | 441 | } |
d15c345f | 442 | |
fcd48280 | 443 | walk_return: |
d15c345f | 444 | rcu_read_unlock(); |
fcd48280 PM |
445 | *skip_bkt = iter_bkt; |
446 | *skip_chain = chain_cnt; | |
447 | return ret_val; | |
d15c345f | 448 | } |