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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); | |
3482fd90 PM |
129 | list_for_each_entry_rcu(iter, |
130 | &rcu_dereference(netlbl_domhsh)->tbl[bkt], | |
131 | list) | |
d15c345f PM |
132 | if (iter->valid && strcmp(iter->domain, domain) == 0) |
133 | return iter; | |
134 | } | |
135 | ||
136 | if (def != 0) { | |
137 | iter = rcu_dereference(netlbl_domhsh_def); | |
138 | if (iter != NULL && iter->valid) | |
139 | return iter; | |
140 | } | |
141 | ||
142 | return NULL; | |
143 | } | |
144 | ||
145 | /* | |
146 | * Domain Hash Table Functions | |
147 | */ | |
148 | ||
149 | /** | |
150 | * netlbl_domhsh_init - Init for the domain hash | |
151 | * @size: the number of bits to use for the hash buckets | |
152 | * | |
153 | * Description: | |
154 | * Initializes the domain hash table, should be called only by | |
155 | * netlbl_user_init() during initialization. Returns zero on success, non-zero | |
156 | * values on error. | |
157 | * | |
158 | */ | |
159 | int netlbl_domhsh_init(u32 size) | |
160 | { | |
161 | u32 iter; | |
162 | struct netlbl_domhsh_tbl *hsh_tbl; | |
163 | ||
164 | if (size == 0) | |
165 | return -EINVAL; | |
166 | ||
167 | hsh_tbl = kmalloc(sizeof(*hsh_tbl), GFP_KERNEL); | |
168 | if (hsh_tbl == NULL) | |
169 | return -ENOMEM; | |
170 | hsh_tbl->size = 1 << size; | |
171 | hsh_tbl->tbl = kcalloc(hsh_tbl->size, | |
172 | sizeof(struct list_head), | |
173 | GFP_KERNEL); | |
174 | if (hsh_tbl->tbl == NULL) { | |
175 | kfree(hsh_tbl); | |
176 | return -ENOMEM; | |
177 | } | |
178 | for (iter = 0; iter < hsh_tbl->size; iter++) | |
179 | INIT_LIST_HEAD(&hsh_tbl->tbl[iter]); | |
180 | ||
181 | rcu_read_lock(); | |
182 | spin_lock(&netlbl_domhsh_lock); | |
183 | rcu_assign_pointer(netlbl_domhsh, hsh_tbl); | |
184 | spin_unlock(&netlbl_domhsh_lock); | |
185 | rcu_read_unlock(); | |
186 | ||
187 | return 0; | |
188 | } | |
189 | ||
190 | /** | |
191 | * netlbl_domhsh_add - Adds a entry to the domain hash table | |
192 | * @entry: the entry to add | |
95d4e6be | 193 | * @audit_info: NetLabel audit information |
d15c345f PM |
194 | * |
195 | * Description: | |
196 | * Adds a new entry to the domain hash table and handles any updates to the | |
197 | * lower level protocol handler (i.e. CIPSO). Returns zero on success, | |
198 | * negative on failure. | |
199 | * | |
200 | */ | |
95d4e6be PM |
201 | int netlbl_domhsh_add(struct netlbl_dom_map *entry, |
202 | struct netlbl_audit *audit_info) | |
d15c345f PM |
203 | { |
204 | int ret_val; | |
205 | u32 bkt; | |
32f50cde | 206 | struct audit_buffer *audit_buf; |
d15c345f PM |
207 | |
208 | switch (entry->type) { | |
209 | case NETLBL_NLTYPE_UNLABELED: | |
210 | ret_val = 0; | |
211 | break; | |
212 | case NETLBL_NLTYPE_CIPSOV4: | |
213 | ret_val = cipso_v4_doi_domhsh_add(entry->type_def.cipsov4, | |
214 | entry->domain); | |
215 | break; | |
216 | default: | |
217 | return -EINVAL; | |
218 | } | |
219 | if (ret_val != 0) | |
220 | return ret_val; | |
221 | ||
222 | entry->valid = 1; | |
223 | INIT_RCU_HEAD(&entry->rcu); | |
224 | ||
225 | ret_val = 0; | |
226 | rcu_read_lock(); | |
227 | if (entry->domain != NULL) { | |
228 | bkt = netlbl_domhsh_hash(entry->domain); | |
229 | spin_lock(&netlbl_domhsh_lock); | |
230 | if (netlbl_domhsh_search(entry->domain, 0) == NULL) | |
231 | list_add_tail_rcu(&entry->list, | |
3482fd90 | 232 | &rcu_dereference(netlbl_domhsh)->tbl[bkt]); |
d15c345f PM |
233 | else |
234 | ret_val = -EEXIST; | |
235 | spin_unlock(&netlbl_domhsh_lock); | |
236 | } else if (entry->domain == NULL) { | |
237 | INIT_LIST_HEAD(&entry->list); | |
238 | spin_lock(&netlbl_domhsh_def_lock); | |
239 | if (rcu_dereference(netlbl_domhsh_def) == NULL) | |
240 | rcu_assign_pointer(netlbl_domhsh_def, entry); | |
241 | else | |
242 | ret_val = -EEXIST; | |
243 | spin_unlock(&netlbl_domhsh_def_lock); | |
244 | } else | |
245 | ret_val = -EINVAL; | |
95d4e6be | 246 | |
95d4e6be | 247 | audit_buf = netlbl_audit_start_common(AUDIT_MAC_MAP_ADD, audit_info); |
de64688f | 248 | if (audit_buf != NULL) { |
95d4e6be | 249 | audit_log_format(audit_buf, |
de64688f PM |
250 | " nlbl_domain=%s", |
251 | entry->domain ? entry->domain : "(default)"); | |
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; | |
261 | } | |
262 | audit_log_format(audit_buf, " res=%u", ret_val == 0 ? 1 : 0); | |
263 | audit_log_end(audit_buf); | |
32f50cde | 264 | } |
95d4e6be | 265 | |
d15c345f PM |
266 | rcu_read_unlock(); |
267 | ||
268 | if (ret_val != 0) { | |
269 | switch (entry->type) { | |
270 | case NETLBL_NLTYPE_CIPSOV4: | |
271 | if (cipso_v4_doi_domhsh_remove(entry->type_def.cipsov4, | |
272 | entry->domain) != 0) | |
273 | BUG(); | |
274 | break; | |
275 | } | |
276 | } | |
277 | ||
278 | return ret_val; | |
279 | } | |
280 | ||
281 | /** | |
282 | * netlbl_domhsh_add_default - Adds the default entry to the domain hash table | |
283 | * @entry: the entry to add | |
95d4e6be | 284 | * @audit_info: NetLabel audit information |
d15c345f PM |
285 | * |
286 | * Description: | |
287 | * Adds a new default entry to the domain hash table and handles any updates | |
288 | * to the lower level protocol handler (i.e. CIPSO). Returns zero on success, | |
289 | * negative on failure. | |
290 | * | |
291 | */ | |
95d4e6be PM |
292 | int netlbl_domhsh_add_default(struct netlbl_dom_map *entry, |
293 | struct netlbl_audit *audit_info) | |
d15c345f | 294 | { |
95d4e6be | 295 | return netlbl_domhsh_add(entry, audit_info); |
d15c345f PM |
296 | } |
297 | ||
298 | /** | |
299 | * netlbl_domhsh_remove - Removes an entry from the domain hash table | |
300 | * @domain: the domain to remove | |
95d4e6be | 301 | * @audit_info: NetLabel audit information |
d15c345f PM |
302 | * |
303 | * Description: | |
304 | * Removes an entry from the domain hash table and handles any updates to the | |
305 | * lower level protocol handler (i.e. CIPSO). Returns zero on success, | |
306 | * negative on failure. | |
307 | * | |
308 | */ | |
95d4e6be | 309 | int netlbl_domhsh_remove(const char *domain, struct netlbl_audit *audit_info) |
d15c345f PM |
310 | { |
311 | int ret_val = -ENOENT; | |
312 | struct netlbl_dom_map *entry; | |
32f50cde | 313 | struct audit_buffer *audit_buf; |
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 | 351 | audit_buf = netlbl_audit_start_common(AUDIT_MAC_MAP_DEL, audit_info); |
de64688f PM |
352 | if (audit_buf != NULL) { |
353 | audit_log_format(audit_buf, | |
354 | " nlbl_domain=%s res=%u", | |
355 | entry->domain ? entry->domain : "(default)", | |
356 | ret_val == 0 ? 1 : 0); | |
357 | audit_log_end(audit_buf); | |
358 | } | |
95d4e6be PM |
359 | |
360 | if (ret_val == 0) | |
d15c345f PM |
361 | call_rcu(&entry->rcu, netlbl_domhsh_free_entry); |
362 | ||
363 | remove_return: | |
364 | rcu_read_unlock(); | |
365 | return ret_val; | |
366 | } | |
367 | ||
368 | /** | |
369 | * netlbl_domhsh_remove_default - Removes the default entry from the table | |
95d4e6be | 370 | * @audit_info: NetLabel audit information |
d15c345f PM |
371 | * |
372 | * Description: | |
373 | * Removes/resets the default entry for the domain hash table and handles any | |
374 | * updates to the lower level protocol handler (i.e. CIPSO). Returns zero on | |
375 | * success, non-zero on failure. | |
376 | * | |
377 | */ | |
95d4e6be | 378 | int netlbl_domhsh_remove_default(struct netlbl_audit *audit_info) |
d15c345f | 379 | { |
95d4e6be | 380 | return netlbl_domhsh_remove(NULL, audit_info); |
d15c345f PM |
381 | } |
382 | ||
383 | /** | |
384 | * netlbl_domhsh_getentry - Get an entry from the domain hash table | |
385 | * @domain: the domain name to search for | |
386 | * | |
387 | * Description: | |
388 | * Look through the domain hash table searching for an entry to match @domain, | |
389 | * return a pointer to a copy of the entry or NULL. The caller is responsibile | |
390 | * for ensuring that rcu_read_[un]lock() is called. | |
391 | * | |
392 | */ | |
393 | struct netlbl_dom_map *netlbl_domhsh_getentry(const char *domain) | |
394 | { | |
395 | return netlbl_domhsh_search(domain, 1); | |
396 | } | |
397 | ||
398 | /** | |
fcd48280 PM |
399 | * netlbl_domhsh_walk - Iterate through the domain mapping hash table |
400 | * @skip_bkt: the number of buckets to skip at the start | |
401 | * @skip_chain: the number of entries to skip in the first iterated bucket | |
402 | * @callback: callback for each entry | |
403 | * @cb_arg: argument for the callback function | |
d15c345f PM |
404 | * |
405 | * Description: | |
fcd48280 PM |
406 | * Interate over the domain mapping hash table, skipping the first @skip_bkt |
407 | * buckets and @skip_chain entries. For each entry in the table call | |
408 | * @callback, if @callback returns a negative value stop 'walking' through the | |
409 | * table and return. Updates the values in @skip_bkt and @skip_chain on | |
410 | * return. Returns zero on succcess, negative values on failure. | |
d15c345f PM |
411 | * |
412 | */ | |
fcd48280 PM |
413 | int netlbl_domhsh_walk(u32 *skip_bkt, |
414 | u32 *skip_chain, | |
415 | int (*callback) (struct netlbl_dom_map *entry, void *arg), | |
416 | void *cb_arg) | |
d15c345f | 417 | { |
fcd48280 PM |
418 | int ret_val = -ENOENT; |
419 | u32 iter_bkt; | |
420 | struct netlbl_dom_map *iter_entry; | |
421 | u32 chain_cnt = 0; | |
d15c345f | 422 | |
d15c345f | 423 | rcu_read_lock(); |
fcd48280 PM |
424 | for (iter_bkt = *skip_bkt; |
425 | iter_bkt < rcu_dereference(netlbl_domhsh)->size; | |
426 | iter_bkt++, chain_cnt = 0) { | |
427 | list_for_each_entry_rcu(iter_entry, | |
3482fd90 PM |
428 | &rcu_dereference(netlbl_domhsh)->tbl[iter_bkt], |
429 | list) | |
fcd48280 PM |
430 | if (iter_entry->valid) { |
431 | if (chain_cnt++ < *skip_chain) | |
432 | continue; | |
433 | ret_val = callback(iter_entry, cb_arg); | |
434 | if (ret_val < 0) { | |
435 | chain_cnt--; | |
436 | goto walk_return; | |
437 | } | |
d15c345f | 438 | } |
fcd48280 | 439 | } |
d15c345f | 440 | |
fcd48280 | 441 | walk_return: |
d15c345f | 442 | rcu_read_unlock(); |
fcd48280 PM |
443 | *skip_bkt = iter_bkt; |
444 | *skip_chain = chain_cnt; | |
445 | return ret_val; | |
d15c345f | 446 | } |