2 * NetLabel Domain Hash Table
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
9 * Author: Paul Moore <paul.moore@hp.com>
14 * (c) Copyright Hewlett-Packard Development Company, L.P., 2006
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.
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.
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
32 #include <linux/types.h>
33 #include <linux/rculist.h>
34 #include <linux/skbuff.h>
35 #include <linux/spinlock.h>
36 #include <linux/string.h>
37 #include <linux/audit.h>
38 #include <net/netlabel.h>
39 #include <net/cipso_ipv4.h>
42 #include "netlabel_mgmt.h"
43 #include "netlabel_domainhash.h"
44 #include "netlabel_user.h"
46 struct netlbl_domhsh_tbl {
47 struct list_head *tbl;
51 /* Domain hash table */
52 /* XXX - updates should be so rare that having one spinlock for the entire
53 * hash table should be okay */
54 static DEFINE_SPINLOCK(netlbl_domhsh_lock);
55 static struct netlbl_domhsh_tbl *netlbl_domhsh = NULL;
56 static struct netlbl_dom_map *netlbl_domhsh_def = NULL;
59 * Domain Hash Table Helper Functions
63 * netlbl_domhsh_free_entry - Frees a domain hash table entry
64 * @entry: the entry's RCU field
67 * This function is designed to be used as a callback to the call_rcu()
68 * function so that the memory allocated to a hash table entry can be released
72 static void netlbl_domhsh_free_entry(struct rcu_head *entry)
74 struct netlbl_dom_map *ptr;
76 ptr = container_of(entry, struct netlbl_dom_map, rcu);
82 * netlbl_domhsh_hash - Hashing function for the domain hash table
83 * @domain: the domain name to hash
86 * This is the hashing function for the domain hash table, it returns the
87 * correct bucket number for the domain. The caller is responsibile for
88 * calling the rcu_read_[un]lock() functions.
91 static u32 netlbl_domhsh_hash(const char *key)
97 /* This is taken (with slight modification) from
98 * security/selinux/ss/symtab.c:symhash() */
100 for (iter = 0, val = 0, len = strlen(key); iter < len; iter++)
101 val = (val << 4 | (val >> (8 * sizeof(u32) - 4))) ^ key[iter];
102 return val & (rcu_dereference(netlbl_domhsh)->size - 1);
106 * netlbl_domhsh_search - Search for a domain entry
107 * @domain: the domain
110 * Searches the domain hash table and returns a pointer to the hash table
111 * entry if found, otherwise NULL is returned. The caller is responsibile for
112 * the rcu hash table locks (i.e. the caller much call rcu_read_[un]lock()).
115 static struct netlbl_dom_map *netlbl_domhsh_search(const char *domain)
118 struct list_head *bkt_list;
119 struct netlbl_dom_map *iter;
121 if (domain != NULL) {
122 bkt = netlbl_domhsh_hash(domain);
123 bkt_list = &rcu_dereference(netlbl_domhsh)->tbl[bkt];
124 list_for_each_entry_rcu(iter, bkt_list, list)
125 if (iter->valid && strcmp(iter->domain, domain) == 0)
133 * netlbl_domhsh_search_def - Search for a domain entry
134 * @domain: the domain
135 * @def: return default if no match is found
138 * Searches the domain hash table and returns a pointer to the hash table
139 * entry if an exact match is found, if an exact match is not present in the
140 * hash table then the default entry is returned if valid otherwise NULL is
141 * returned. The caller is responsibile for the rcu hash table locks
142 * (i.e. the caller much call rcu_read_[un]lock()).
145 static struct netlbl_dom_map *netlbl_domhsh_search_def(const char *domain)
147 struct netlbl_dom_map *entry;
149 entry = netlbl_domhsh_search(domain);
151 entry = rcu_dereference(netlbl_domhsh_def);
152 if (entry != NULL && !entry->valid)
160 * Domain Hash Table Functions
164 * netlbl_domhsh_init - Init for the domain hash
165 * @size: the number of bits to use for the hash buckets
168 * Initializes the domain hash table, should be called only by
169 * netlbl_user_init() during initialization. Returns zero on success, non-zero
173 int __init netlbl_domhsh_init(u32 size)
176 struct netlbl_domhsh_tbl *hsh_tbl;
181 hsh_tbl = kmalloc(sizeof(*hsh_tbl), GFP_KERNEL);
184 hsh_tbl->size = 1 << size;
185 hsh_tbl->tbl = kcalloc(hsh_tbl->size,
186 sizeof(struct list_head),
188 if (hsh_tbl->tbl == NULL) {
192 for (iter = 0; iter < hsh_tbl->size; iter++)
193 INIT_LIST_HEAD(&hsh_tbl->tbl[iter]);
195 spin_lock(&netlbl_domhsh_lock);
196 rcu_assign_pointer(netlbl_domhsh, hsh_tbl);
197 spin_unlock(&netlbl_domhsh_lock);
203 * netlbl_domhsh_add - Adds a entry to the domain hash table
204 * @entry: the entry to add
205 * @audit_info: NetLabel audit information
208 * Adds a new entry to the domain hash table and handles any updates to the
209 * lower level protocol handler (i.e. CIPSO). Returns zero on success,
210 * negative on failure.
213 int netlbl_domhsh_add(struct netlbl_dom_map *entry,
214 struct netlbl_audit *audit_info)
218 struct audit_buffer *audit_buf;
221 INIT_RCU_HEAD(&entry->rcu);
224 spin_lock(&netlbl_domhsh_lock);
225 if (entry->domain != NULL) {
226 bkt = netlbl_domhsh_hash(entry->domain);
227 if (netlbl_domhsh_search(entry->domain) == NULL)
228 list_add_tail_rcu(&entry->list,
229 &rcu_dereference(netlbl_domhsh)->tbl[bkt]);
233 INIT_LIST_HEAD(&entry->list);
234 if (rcu_dereference(netlbl_domhsh_def) == NULL)
235 rcu_assign_pointer(netlbl_domhsh_def, entry);
239 spin_unlock(&netlbl_domhsh_lock);
240 audit_buf = netlbl_audit_start_common(AUDIT_MAC_MAP_ADD, audit_info);
241 if (audit_buf != NULL) {
242 audit_log_format(audit_buf,
244 entry->domain ? entry->domain : "(default)");
245 switch (entry->type) {
246 case NETLBL_NLTYPE_UNLABELED:
247 audit_log_format(audit_buf, " nlbl_protocol=unlbl");
249 case NETLBL_NLTYPE_CIPSOV4:
250 audit_log_format(audit_buf,
251 " nlbl_protocol=cipsov4 cipso_doi=%u",
252 entry->type_def.cipsov4->doi);
255 audit_log_format(audit_buf, " res=%u", ret_val == 0 ? 1 : 0);
256 audit_log_end(audit_buf);
264 * netlbl_domhsh_add_default - Adds the default entry to the domain hash table
265 * @entry: the entry to add
266 * @audit_info: NetLabel audit information
269 * Adds a new default entry to the domain hash table and handles any updates
270 * to the lower level protocol handler (i.e. CIPSO). Returns zero on success,
271 * negative on failure.
274 int netlbl_domhsh_add_default(struct netlbl_dom_map *entry,
275 struct netlbl_audit *audit_info)
277 return netlbl_domhsh_add(entry, audit_info);
281 * netlbl_domhsh_remove_entry - Removes a given entry from the domain table
282 * @entry: the entry to remove
283 * @audit_info: NetLabel audit information
286 * Removes an entry from the domain hash table and handles any updates to the
287 * lower level protocol handler (i.e. CIPSO). Caller is responsible for
288 * ensuring that the RCU read lock is held. Returns zero on success, negative
292 int netlbl_domhsh_remove_entry(struct netlbl_dom_map *entry,
293 struct netlbl_audit *audit_info)
296 struct audit_buffer *audit_buf;
301 spin_lock(&netlbl_domhsh_lock);
304 if (entry != rcu_dereference(netlbl_domhsh_def))
305 list_del_rcu(&entry->list);
307 rcu_assign_pointer(netlbl_domhsh_def, NULL);
310 spin_unlock(&netlbl_domhsh_lock);
312 audit_buf = netlbl_audit_start_common(AUDIT_MAC_MAP_DEL, audit_info);
313 if (audit_buf != NULL) {
314 audit_log_format(audit_buf,
315 " nlbl_domain=%s res=%u",
316 entry->domain ? entry->domain : "(default)",
317 ret_val == 0 ? 1 : 0);
318 audit_log_end(audit_buf);
322 switch (entry->type) {
323 case NETLBL_NLTYPE_CIPSOV4:
324 cipso_v4_doi_putdef(entry->type_def.cipsov4);
327 call_rcu(&entry->rcu, netlbl_domhsh_free_entry);
334 * netlbl_domhsh_remove - Removes an entry from the domain hash table
335 * @domain: the domain to remove
336 * @audit_info: NetLabel audit information
339 * Removes an entry from the domain hash table and handles any updates to the
340 * lower level protocol handler (i.e. CIPSO). Returns zero on success,
341 * negative on failure.
344 int netlbl_domhsh_remove(const char *domain, struct netlbl_audit *audit_info)
347 struct netlbl_dom_map *entry;
351 entry = netlbl_domhsh_search(domain);
353 entry = netlbl_domhsh_search_def(domain);
354 ret_val = netlbl_domhsh_remove_entry(entry, audit_info);
361 * netlbl_domhsh_remove_default - Removes the default entry from the table
362 * @audit_info: NetLabel audit information
365 * Removes/resets the default entry for the domain hash table and handles any
366 * updates to the lower level protocol handler (i.e. CIPSO). Returns zero on
367 * success, non-zero on failure.
370 int netlbl_domhsh_remove_default(struct netlbl_audit *audit_info)
372 return netlbl_domhsh_remove(NULL, audit_info);
376 * netlbl_domhsh_getentry - Get an entry from the domain hash table
377 * @domain: the domain name to search for
380 * Look through the domain hash table searching for an entry to match @domain,
381 * return a pointer to a copy of the entry or NULL. The caller is responsibile
382 * for ensuring that rcu_read_[un]lock() is called.
385 struct netlbl_dom_map *netlbl_domhsh_getentry(const char *domain)
387 return netlbl_domhsh_search_def(domain);
391 * netlbl_domhsh_walk - Iterate through the domain mapping hash table
392 * @skip_bkt: the number of buckets to skip at the start
393 * @skip_chain: the number of entries to skip in the first iterated bucket
394 * @callback: callback for each entry
395 * @cb_arg: argument for the callback function
398 * Interate over the domain mapping hash table, skipping the first @skip_bkt
399 * buckets and @skip_chain entries. For each entry in the table call
400 * @callback, if @callback returns a negative value stop 'walking' through the
401 * table and return. Updates the values in @skip_bkt and @skip_chain on
402 * return. Returns zero on succcess, negative values on failure.
405 int netlbl_domhsh_walk(u32 *skip_bkt,
407 int (*callback) (struct netlbl_dom_map *entry, void *arg),
410 int ret_val = -ENOENT;
412 struct list_head *iter_list;
413 struct netlbl_dom_map *iter_entry;
417 for (iter_bkt = *skip_bkt;
418 iter_bkt < rcu_dereference(netlbl_domhsh)->size;
419 iter_bkt++, chain_cnt = 0) {
420 iter_list = &rcu_dereference(netlbl_domhsh)->tbl[iter_bkt];
421 list_for_each_entry_rcu(iter_entry, iter_list, list)
422 if (iter_entry->valid) {
423 if (chain_cnt++ < *skip_chain)
425 ret_val = callback(iter_entry, cb_arg);
435 *skip_bkt = iter_bkt;
436 *skip_chain = chain_cnt;