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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 | 56 | static struct netlbl_domhsh_tbl *netlbl_domhsh = NULL; |
d15c345f PM |
57 | static struct netlbl_dom_map *netlbl_domhsh_def = NULL; |
58 | ||
59 | /* | |
60 | * Domain Hash Table Helper Functions | |
61 | */ | |
62 | ||
63 | /** | |
64 | * netlbl_domhsh_free_entry - Frees a domain hash table entry | |
65 | * @entry: the entry's RCU field | |
66 | * | |
67 | * Description: | |
68 | * This function is designed to be used as a callback to the call_rcu() | |
69 | * function so that the memory allocated to a hash table entry can be released | |
70 | * safely. | |
71 | * | |
72 | */ | |
73 | static void netlbl_domhsh_free_entry(struct rcu_head *entry) | |
74 | { | |
75 | struct netlbl_dom_map *ptr; | |
76 | ||
77 | ptr = container_of(entry, struct netlbl_dom_map, rcu); | |
78 | kfree(ptr->domain); | |
79 | kfree(ptr); | |
80 | } | |
81 | ||
82 | /** | |
83 | * netlbl_domhsh_hash - Hashing function for the domain hash table | |
84 | * @domain: the domain name to hash | |
85 | * | |
86 | * Description: | |
87 | * This is the hashing function for the domain hash table, it returns the | |
88 | * correct bucket number for the domain. The caller is responsibile for | |
89 | * calling the rcu_read_[un]lock() functions. | |
90 | * | |
91 | */ | |
92 | static u32 netlbl_domhsh_hash(const char *key) | |
93 | { | |
94 | u32 iter; | |
95 | u32 val; | |
96 | u32 len; | |
97 | ||
98 | /* This is taken (with slight modification) from | |
99 | * security/selinux/ss/symtab.c:symhash() */ | |
100 | ||
101 | for (iter = 0, val = 0, len = strlen(key); iter < len; iter++) | |
102 | val = (val << 4 | (val >> (8 * sizeof(u32) - 4))) ^ key[iter]; | |
103 | return val & (rcu_dereference(netlbl_domhsh)->size - 1); | |
104 | } | |
105 | ||
106 | /** | |
107 | * netlbl_domhsh_search - Search for a domain entry | |
108 | * @domain: the domain | |
d15c345f PM |
109 | * |
110 | * Description: | |
111 | * Searches the domain hash table and returns a pointer to the hash table | |
b64397e0 PM |
112 | * entry if found, otherwise NULL is returned. The caller is responsibile for |
113 | * the rcu hash table locks (i.e. the caller much call rcu_read_[un]lock()). | |
d15c345f PM |
114 | * |
115 | */ | |
b64397e0 | 116 | static struct netlbl_dom_map *netlbl_domhsh_search(const char *domain) |
d15c345f PM |
117 | { |
118 | u32 bkt; | |
119 | struct netlbl_dom_map *iter; | |
120 | ||
121 | if (domain != NULL) { | |
122 | bkt = netlbl_domhsh_hash(domain); | |
3482fd90 PM |
123 | list_for_each_entry_rcu(iter, |
124 | &rcu_dereference(netlbl_domhsh)->tbl[bkt], | |
125 | list) | |
d15c345f PM |
126 | if (iter->valid && strcmp(iter->domain, domain) == 0) |
127 | return iter; | |
128 | } | |
129 | ||
b64397e0 PM |
130 | return NULL; |
131 | } | |
132 | ||
133 | /** | |
134 | * netlbl_domhsh_search_def - Search for a domain entry | |
135 | * @domain: the domain | |
136 | * @def: return default if no match is found | |
137 | * | |
138 | * Description: | |
139 | * Searches the domain hash table and returns a pointer to the hash table | |
140 | * entry if an exact match is found, if an exact match is not present in the | |
141 | * hash table then the default entry is returned if valid otherwise NULL is | |
142 | * returned. The caller is responsibile for the rcu hash table locks | |
143 | * (i.e. the caller much call rcu_read_[un]lock()). | |
144 | * | |
145 | */ | |
146 | static struct netlbl_dom_map *netlbl_domhsh_search_def(const char *domain) | |
147 | { | |
148 | struct netlbl_dom_map *entry; | |
149 | ||
150 | entry = netlbl_domhsh_search(domain); | |
151 | if (entry == NULL) { | |
152 | entry = rcu_dereference(netlbl_domhsh_def); | |
4c3a0a25 PE |
153 | if (entry != NULL && !entry->valid) |
154 | entry = NULL; | |
d15c345f PM |
155 | } |
156 | ||
4c3a0a25 | 157 | return entry; |
d15c345f PM |
158 | } |
159 | ||
160 | /* | |
161 | * Domain Hash Table Functions | |
162 | */ | |
163 | ||
164 | /** | |
165 | * netlbl_domhsh_init - Init for the domain hash | |
166 | * @size: the number of bits to use for the hash buckets | |
167 | * | |
168 | * Description: | |
169 | * Initializes the domain hash table, should be called only by | |
170 | * netlbl_user_init() during initialization. Returns zero on success, non-zero | |
171 | * values on error. | |
172 | * | |
173 | */ | |
05705e4e | 174 | int __init netlbl_domhsh_init(u32 size) |
d15c345f PM |
175 | { |
176 | u32 iter; | |
177 | struct netlbl_domhsh_tbl *hsh_tbl; | |
178 | ||
179 | if (size == 0) | |
180 | return -EINVAL; | |
181 | ||
182 | hsh_tbl = kmalloc(sizeof(*hsh_tbl), GFP_KERNEL); | |
183 | if (hsh_tbl == NULL) | |
184 | return -ENOMEM; | |
185 | hsh_tbl->size = 1 << size; | |
186 | hsh_tbl->tbl = kcalloc(hsh_tbl->size, | |
187 | sizeof(struct list_head), | |
188 | GFP_KERNEL); | |
189 | if (hsh_tbl->tbl == NULL) { | |
190 | kfree(hsh_tbl); | |
191 | return -ENOMEM; | |
192 | } | |
193 | for (iter = 0; iter < hsh_tbl->size; iter++) | |
194 | INIT_LIST_HEAD(&hsh_tbl->tbl[iter]); | |
195 | ||
d15c345f PM |
196 | spin_lock(&netlbl_domhsh_lock); |
197 | rcu_assign_pointer(netlbl_domhsh, hsh_tbl); | |
198 | spin_unlock(&netlbl_domhsh_lock); | |
d15c345f PM |
199 | |
200 | return 0; | |
201 | } | |
202 | ||
203 | /** | |
204 | * netlbl_domhsh_add - Adds a entry to the domain hash table | |
205 | * @entry: the entry to add | |
95d4e6be | 206 | * @audit_info: NetLabel audit information |
d15c345f PM |
207 | * |
208 | * Description: | |
209 | * Adds a new entry to the domain hash table and handles any updates to the | |
210 | * lower level protocol handler (i.e. CIPSO). Returns zero on success, | |
211 | * negative on failure. | |
212 | * | |
213 | */ | |
95d4e6be PM |
214 | int netlbl_domhsh_add(struct netlbl_dom_map *entry, |
215 | struct netlbl_audit *audit_info) | |
d15c345f PM |
216 | { |
217 | int ret_val; | |
218 | u32 bkt; | |
32f50cde | 219 | struct audit_buffer *audit_buf; |
d15c345f PM |
220 | |
221 | switch (entry->type) { | |
222 | case NETLBL_NLTYPE_UNLABELED: | |
223 | ret_val = 0; | |
224 | break; | |
225 | case NETLBL_NLTYPE_CIPSOV4: | |
226 | ret_val = cipso_v4_doi_domhsh_add(entry->type_def.cipsov4, | |
227 | entry->domain); | |
228 | break; | |
229 | default: | |
230 | return -EINVAL; | |
231 | } | |
232 | if (ret_val != 0) | |
233 | return ret_val; | |
234 | ||
235 | entry->valid = 1; | |
236 | INIT_RCU_HEAD(&entry->rcu); | |
237 | ||
d15c345f | 238 | rcu_read_lock(); |
1c3fad93 | 239 | spin_lock(&netlbl_domhsh_lock); |
d15c345f PM |
240 | if (entry->domain != NULL) { |
241 | bkt = netlbl_domhsh_hash(entry->domain); | |
b64397e0 | 242 | if (netlbl_domhsh_search(entry->domain) == NULL) |
d15c345f | 243 | list_add_tail_rcu(&entry->list, |
3482fd90 | 244 | &rcu_dereference(netlbl_domhsh)->tbl[bkt]); |
d15c345f PM |
245 | else |
246 | ret_val = -EEXIST; | |
4be2700f | 247 | } else { |
d15c345f | 248 | INIT_LIST_HEAD(&entry->list); |
d15c345f PM |
249 | if (rcu_dereference(netlbl_domhsh_def) == NULL) |
250 | rcu_assign_pointer(netlbl_domhsh_def, entry); | |
251 | else | |
252 | ret_val = -EEXIST; | |
4be2700f | 253 | } |
1c3fad93 | 254 | spin_unlock(&netlbl_domhsh_lock); |
95d4e6be | 255 | audit_buf = netlbl_audit_start_common(AUDIT_MAC_MAP_ADD, audit_info); |
de64688f | 256 | if (audit_buf != NULL) { |
95d4e6be | 257 | audit_log_format(audit_buf, |
de64688f PM |
258 | " nlbl_domain=%s", |
259 | entry->domain ? entry->domain : "(default)"); | |
260 | switch (entry->type) { | |
261 | case NETLBL_NLTYPE_UNLABELED: | |
262 | audit_log_format(audit_buf, " nlbl_protocol=unlbl"); | |
263 | break; | |
264 | case NETLBL_NLTYPE_CIPSOV4: | |
265 | audit_log_format(audit_buf, | |
266 | " nlbl_protocol=cipsov4 cipso_doi=%u", | |
267 | entry->type_def.cipsov4->doi); | |
268 | break; | |
269 | } | |
270 | audit_log_format(audit_buf, " res=%u", ret_val == 0 ? 1 : 0); | |
271 | audit_log_end(audit_buf); | |
32f50cde | 272 | } |
d15c345f PM |
273 | rcu_read_unlock(); |
274 | ||
275 | if (ret_val != 0) { | |
276 | switch (entry->type) { | |
277 | case NETLBL_NLTYPE_CIPSOV4: | |
278 | if (cipso_v4_doi_domhsh_remove(entry->type_def.cipsov4, | |
279 | entry->domain) != 0) | |
280 | BUG(); | |
281 | break; | |
282 | } | |
283 | } | |
284 | ||
285 | return ret_val; | |
286 | } | |
287 | ||
288 | /** | |
289 | * netlbl_domhsh_add_default - Adds the default entry to the domain hash table | |
290 | * @entry: the entry to add | |
95d4e6be | 291 | * @audit_info: NetLabel audit information |
d15c345f PM |
292 | * |
293 | * Description: | |
294 | * Adds a new default entry to the domain hash table and handles any updates | |
295 | * to the lower level protocol handler (i.e. CIPSO). Returns zero on success, | |
296 | * negative on failure. | |
297 | * | |
298 | */ | |
95d4e6be PM |
299 | int netlbl_domhsh_add_default(struct netlbl_dom_map *entry, |
300 | struct netlbl_audit *audit_info) | |
d15c345f | 301 | { |
95d4e6be | 302 | return netlbl_domhsh_add(entry, audit_info); |
d15c345f PM |
303 | } |
304 | ||
305 | /** | |
306 | * netlbl_domhsh_remove - Removes an entry from the domain hash table | |
307 | * @domain: the domain to remove | |
95d4e6be | 308 | * @audit_info: NetLabel audit information |
d15c345f PM |
309 | * |
310 | * Description: | |
311 | * Removes an entry from the domain hash table and handles any updates to the | |
312 | * lower level protocol handler (i.e. CIPSO). Returns zero on success, | |
313 | * negative on failure. | |
314 | * | |
315 | */ | |
95d4e6be | 316 | int netlbl_domhsh_remove(const char *domain, struct netlbl_audit *audit_info) |
d15c345f PM |
317 | { |
318 | int ret_val = -ENOENT; | |
319 | struct netlbl_dom_map *entry; | |
32f50cde | 320 | struct audit_buffer *audit_buf; |
d15c345f PM |
321 | |
322 | rcu_read_lock(); | |
b64397e0 PM |
323 | if (domain) |
324 | entry = netlbl_domhsh_search(domain); | |
325 | else | |
326 | entry = netlbl_domhsh_search_def(domain); | |
d15c345f PM |
327 | if (entry == NULL) |
328 | goto remove_return; | |
329 | switch (entry->type) { | |
d15c345f | 330 | case NETLBL_NLTYPE_CIPSOV4: |
4be2700f PM |
331 | cipso_v4_doi_domhsh_remove(entry->type_def.cipsov4, |
332 | entry->domain); | |
d15c345f PM |
333 | break; |
334 | } | |
1c3fad93 PM |
335 | spin_lock(&netlbl_domhsh_lock); |
336 | if (entry->valid) { | |
337 | entry->valid = 0; | |
338 | if (entry != rcu_dereference(netlbl_domhsh_def)) | |
d15c345f | 339 | list_del_rcu(&entry->list); |
1c3fad93 | 340 | else |
d15c345f | 341 | rcu_assign_pointer(netlbl_domhsh_def, NULL); |
1c3fad93 | 342 | ret_val = 0; |
d15c345f | 343 | } |
1c3fad93 | 344 | spin_unlock(&netlbl_domhsh_lock); |
32f50cde | 345 | |
95d4e6be | 346 | audit_buf = netlbl_audit_start_common(AUDIT_MAC_MAP_DEL, audit_info); |
de64688f PM |
347 | if (audit_buf != NULL) { |
348 | audit_log_format(audit_buf, | |
349 | " nlbl_domain=%s res=%u", | |
350 | entry->domain ? entry->domain : "(default)", | |
351 | ret_val == 0 ? 1 : 0); | |
352 | audit_log_end(audit_buf); | |
353 | } | |
95d4e6be | 354 | |
d15c345f PM |
355 | remove_return: |
356 | rcu_read_unlock(); | |
4be2700f PM |
357 | if (ret_val == 0) |
358 | call_rcu(&entry->rcu, netlbl_domhsh_free_entry); | |
d15c345f PM |
359 | return ret_val; |
360 | } | |
361 | ||
362 | /** | |
363 | * netlbl_domhsh_remove_default - Removes the default entry from the table | |
95d4e6be | 364 | * @audit_info: NetLabel audit information |
d15c345f PM |
365 | * |
366 | * Description: | |
367 | * Removes/resets the default entry for the domain hash table and handles any | |
368 | * updates to the lower level protocol handler (i.e. CIPSO). Returns zero on | |
369 | * success, non-zero on failure. | |
370 | * | |
371 | */ | |
95d4e6be | 372 | int netlbl_domhsh_remove_default(struct netlbl_audit *audit_info) |
d15c345f | 373 | { |
95d4e6be | 374 | return netlbl_domhsh_remove(NULL, audit_info); |
d15c345f PM |
375 | } |
376 | ||
377 | /** | |
378 | * netlbl_domhsh_getentry - Get an entry from the domain hash table | |
379 | * @domain: the domain name to search for | |
380 | * | |
381 | * Description: | |
382 | * Look through the domain hash table searching for an entry to match @domain, | |
383 | * return a pointer to a copy of the entry or NULL. The caller is responsibile | |
384 | * for ensuring that rcu_read_[un]lock() is called. | |
385 | * | |
386 | */ | |
387 | struct netlbl_dom_map *netlbl_domhsh_getentry(const char *domain) | |
388 | { | |
b64397e0 | 389 | return netlbl_domhsh_search_def(domain); |
d15c345f PM |
390 | } |
391 | ||
392 | /** | |
fcd48280 PM |
393 | * netlbl_domhsh_walk - Iterate through the domain mapping hash table |
394 | * @skip_bkt: the number of buckets to skip at the start | |
395 | * @skip_chain: the number of entries to skip in the first iterated bucket | |
396 | * @callback: callback for each entry | |
397 | * @cb_arg: argument for the callback function | |
d15c345f PM |
398 | * |
399 | * Description: | |
fcd48280 PM |
400 | * Interate over the domain mapping hash table, skipping the first @skip_bkt |
401 | * buckets and @skip_chain entries. For each entry in the table call | |
402 | * @callback, if @callback returns a negative value stop 'walking' through the | |
403 | * table and return. Updates the values in @skip_bkt and @skip_chain on | |
404 | * return. Returns zero on succcess, negative values on failure. | |
d15c345f PM |
405 | * |
406 | */ | |
fcd48280 PM |
407 | int netlbl_domhsh_walk(u32 *skip_bkt, |
408 | u32 *skip_chain, | |
409 | int (*callback) (struct netlbl_dom_map *entry, void *arg), | |
410 | void *cb_arg) | |
d15c345f | 411 | { |
fcd48280 PM |
412 | int ret_val = -ENOENT; |
413 | u32 iter_bkt; | |
414 | struct netlbl_dom_map *iter_entry; | |
415 | u32 chain_cnt = 0; | |
d15c345f | 416 | |
d15c345f | 417 | rcu_read_lock(); |
fcd48280 PM |
418 | for (iter_bkt = *skip_bkt; |
419 | iter_bkt < rcu_dereference(netlbl_domhsh)->size; | |
420 | iter_bkt++, chain_cnt = 0) { | |
421 | list_for_each_entry_rcu(iter_entry, | |
3482fd90 PM |
422 | &rcu_dereference(netlbl_domhsh)->tbl[iter_bkt], |
423 | list) | |
fcd48280 PM |
424 | if (iter_entry->valid) { |
425 | if (chain_cnt++ < *skip_chain) | |
426 | continue; | |
427 | ret_val = callback(iter_entry, cb_arg); | |
428 | if (ret_val < 0) { | |
429 | chain_cnt--; | |
430 | goto walk_return; | |
431 | } | |
d15c345f | 432 | } |
fcd48280 | 433 | } |
d15c345f | 434 | |
fcd48280 | 435 | walk_return: |
d15c345f | 436 | rcu_read_unlock(); |
fcd48280 PM |
437 | *skip_bkt = iter_bkt; |
438 | *skip_chain = chain_cnt; | |
439 | return ret_val; | |
d15c345f | 440 | } |