/* * NetLabel Domain Hash Table * * This file manages the domain hash table that NetLabel uses to determine * which network labeling protocol to use for a given domain. The NetLabel * system manages static and dynamic label mappings for network protocols such * as CIPSO and RIPSO. * * Author: Paul Moore <paul@paul-moore.com> * */ /* * (c) Copyright Hewlett-Packard Development Company, L.P., 2006, 2008 * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See * the GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * */ #include <linux/types.h> #include <linux/rculist.h> #include <linux/skbuff.h> #include <linux/spinlock.h> #include <linux/string.h> #include <linux/audit.h> #include <linux/slab.h> #include <net/netlabel.h> #include <net/cipso_ipv4.h> #include <asm/bug.h> #include "netlabel_mgmt.h" #include "netlabel_addrlist.h" #include "netlabel_domainhash.h" #include "netlabel_user.h" struct netlbl_domhsh_tbl { struct list_head *tbl; u32 size; }; /* Domain hash table */ /* updates should be so rare that having one spinlock for the entire hash table * should be okay */ static DEFINE_SPINLOCK(netlbl_domhsh_lock); #define netlbl_domhsh_rcu_deref(p) \ rcu_dereference_check(p, lockdep_is_held(&netlbl_domhsh_lock)) static struct netlbl_domhsh_tbl *netlbl_domhsh = NULL; static struct netlbl_dom_map *netlbl_domhsh_def = NULL; /* * Domain Hash Table Helper Functions */ /** * netlbl_domhsh_free_entry - Frees a domain hash table entry * @entry: the entry's RCU field * * Description: * This function is designed to be used as a callback to the call_rcu() * function so that the memory allocated to a hash table entry can be released * safely. * */ static void netlbl_domhsh_free_entry(struct rcu_head *entry) { struct netlbl_dom_map *ptr; struct netlbl_af4list *iter4; struct netlbl_af4list *tmp4; #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) struct netlbl_af6list *iter6; struct netlbl_af6list *tmp6; #endif /* IPv6 */ ptr = container_of(entry, struct netlbl_dom_map, rcu); if (ptr->type == NETLBL_NLTYPE_ADDRSELECT) { netlbl_af4list_foreach_safe(iter4, tmp4, &ptr->type_def.addrsel->list4) { netlbl_af4list_remove_entry(iter4); kfree(netlbl_domhsh_addr4_entry(iter4)); } #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) netlbl_af6list_foreach_safe(iter6, tmp6, &ptr->type_def.addrsel->list6) { netlbl_af6list_remove_entry(iter6); kfree(netlbl_domhsh_addr6_entry(iter6)); } #endif /* IPv6 */ } kfree(ptr->domain); kfree(ptr); } /** * netlbl_domhsh_hash - Hashing function for the domain hash table * @domain: the domain name to hash * * Description: * This is the hashing function for the domain hash table, it returns the * correct bucket number for the domain. The caller is responsible for * ensuring that the hash table is protected with either a RCU read lock or the * hash table lock. * */ static u32 netlbl_domhsh_hash(const char *key) { u32 iter; u32 val; u32 len; /* This is taken (with slight modification) from * security/selinux/ss/symtab.c:symhash() */ for (iter = 0, val = 0, len = strlen(key); iter < len; iter++) val = (val << 4 | (val >> (8 * sizeof(u32) - 4))) ^ key[iter]; return val & (netlbl_domhsh_rcu_deref(netlbl_domhsh)->size - 1); } /** * netlbl_domhsh_search - Search for a domain entry * @domain: the domain * * Description: * Searches the domain hash table and returns a pointer to the hash table * entry if found, otherwise NULL is returned. The caller is responsible for * ensuring that the hash table is protected with either a RCU read lock or the * hash table lock. * */ static struct netlbl_dom_map *netlbl_domhsh_search(const char *domain) { u32 bkt; struct list_head *bkt_list; struct netlbl_dom_map *iter; if (domain != NULL) { bkt = netlbl_domhsh_hash(domain); bkt_list = &netlbl_domhsh_rcu_deref(netlbl_domhsh)->tbl[bkt]; list_for_each_entry_rcu(iter, bkt_list, list) if (iter->valid && strcmp(iter->domain, domain) == 0) return iter; } return NULL; } /** * netlbl_domhsh_search_def - Search for a domain entry * @domain: the domain * @def: return default if no match is found * * Description: * Searches the domain hash table and returns a pointer to the hash table * entry if an exact match is found, if an exact match is not present in the * hash table then the default entry is returned if valid otherwise NULL is * returned. The caller is responsible ensuring that the hash table is * protected with either a RCU read lock or the hash table lock. * */ static struct netlbl_dom_map *netlbl_domhsh_search_def(const char *domain) { struct netlbl_dom_map *entry; entry = netlbl_domhsh_search(domain); if (entry == NULL) { entry = netlbl_domhsh_rcu_deref(netlbl_domhsh_def); if (entry != NULL && !entry->valid) entry = NULL; } return entry; } /** * netlbl_domhsh_audit_add - Generate an audit entry for an add event * @entry: the entry being added * @addr4: the IPv4 address information * @addr6: the IPv6 address information * @result: the result code * @audit_info: NetLabel audit information * * Description: * Generate an audit record for adding a new NetLabel/LSM mapping entry with * the given information. Caller is responsible for holding the necessary * locks. * */ static void netlbl_domhsh_audit_add(struct netlbl_dom_map *entry, struct netlbl_af4list *addr4, struct netlbl_af6list *addr6, int result, struct netlbl_audit *audit_info) { struct audit_buffer *audit_buf; struct cipso_v4_doi *cipsov4 = NULL; u32 type; audit_buf = netlbl_audit_start_common(AUDIT_MAC_MAP_ADD, audit_info); if (audit_buf != NULL) { audit_log_format(audit_buf, " nlbl_domain=%s", entry->domain ? entry->domain : "(default)"); if (addr4 != NULL) { struct netlbl_domaddr4_map *map4; map4 = netlbl_domhsh_addr4_entry(addr4); type = map4->type; cipsov4 = map4->type_def.cipsov4; netlbl_af4list_audit_addr(audit_buf, 0, NULL, addr4->addr, addr4->mask); #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) } else if (addr6 != NULL) { struct netlbl_domaddr6_map *map6; map6 = netlbl_domhsh_addr6_entry(addr6); type = map6->type; netlbl_af6list_audit_addr(audit_buf, 0, NULL, &addr6->addr, &addr6->mask); #endif /* IPv6 */ } else { type = entry->type; cipsov4 = entry->type_def.cipsov4; } switch (type) { case NETLBL_NLTYPE_UNLABELED: audit_log_format(audit_buf, " nlbl_protocol=unlbl"); break; case NETLBL_NLTYPE_CIPSOV4: BUG_ON(cipsov4 == NULL); audit_log_format(audit_buf, " nlbl_protocol=cipsov4 cipso_doi=%u", cipsov4->doi); break; } audit_log_format(audit_buf, " res=%u", result == 0 ? 1 : 0); audit_log_end(audit_buf); } } /* * Domain Hash Table Functions */ /** * netlbl_domhsh_init - Init for the domain hash * @size: the number of bits to use for the hash buckets * * Description: * Initializes the domain hash table, should be called only by * netlbl_user_init() during initialization. Returns zero on success, non-zero * values on error. * */ int __init netlbl_domhsh_init(u32 size) { u32 iter; struct netlbl_domhsh_tbl *hsh_tbl; if (size == 0) return -EINVAL; hsh_tbl = kmalloc(sizeof(*hsh_tbl), GFP_KERNEL); if (hsh_tbl == NULL) return -ENOMEM; hsh_tbl->size = 1 << size; hsh_tbl->tbl = kcalloc(hsh_tbl->size, sizeof(struct list_head), GFP_KERNEL); if (hsh_tbl->tbl == NULL) { kfree(hsh_tbl); return -ENOMEM; } for (iter = 0; iter < hsh_tbl->size; iter++) INIT_LIST_HEAD(&hsh_tbl->tbl[iter]); spin_lock(&netlbl_domhsh_lock); RCU_INIT_POINTER(netlbl_domhsh, hsh_tbl); spin_unlock(&netlbl_domhsh_lock); return 0; } /** * netlbl_domhsh_add - Adds a entry to the domain hash table * @entry: the entry to add * @audit_info: NetLabel audit information * * Description: * Adds a new entry to the domain hash table and handles any updates to the * lower level protocol handler (i.e. CIPSO). Returns zero on success, * negative on failure. * */ int netlbl_domhsh_add(struct netlbl_dom_map *entry, struct netlbl_audit *audit_info) { int ret_val = 0; struct netlbl_dom_map *entry_old; struct netlbl_af4list *iter4; struct netlbl_af4list *tmp4; #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) struct netlbl_af6list *iter6; struct netlbl_af6list *tmp6; #endif /* IPv6 */ /* XXX - we can remove this RCU read lock as the spinlock protects the * entire function, but before we do we need to fixup the * netlbl_af[4,6]list RCU functions to do "the right thing" with * respect to rcu_dereference() when only a spinlock is held. */ rcu_read_lock(); spin_lock(&netlbl_domhsh_lock); if (entry->domain != NULL) entry_old = netlbl_domhsh_search(entry->domain); else entry_old = netlbl_domhsh_search_def(entry->domain); if (entry_old == NULL) { entry->valid = 1; if (entry->domain != NULL) { u32 bkt = netlbl_domhsh_hash(entry->domain); list_add_tail_rcu(&entry->list, &rcu_dereference(netlbl_domhsh)->tbl[bkt]); } else { INIT_LIST_HEAD(&entry->list); RCU_INIT_POINTER(netlbl_domhsh_def, entry); } if (entry->type == NETLBL_NLTYPE_ADDRSELECT) { netlbl_af4list_foreach_rcu(iter4, &entry->type_def.addrsel->list4) netlbl_domhsh_audit_add(entry, iter4, NULL, ret_val, audit_info); #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) netlbl_af6list_foreach_rcu(iter6, &entry->type_def.addrsel->list6) netlbl_domhsh_audit_add(entry, NULL, iter6, ret_val, audit_info); #endif /* IPv6 */ } else netlbl_domhsh_audit_add(entry, NULL, NULL, ret_val, audit_info); } else if (entry_old->type == NETLBL_NLTYPE_ADDRSELECT && entry->type == NETLBL_NLTYPE_ADDRSELECT) { struct list_head *old_list4; struct list_head *old_list6; old_list4 = &entry_old->type_def.addrsel->list4; old_list6 = &entry_old->type_def.addrsel->list6; /* we only allow the addition of address selectors if all of * the selectors do not exist in the existing domain map */ netlbl_af4list_foreach_rcu(iter4, &entry->type_def.addrsel->list4) if (netlbl_af4list_search_exact(iter4->addr, iter4->mask, old_list4)) { ret_val = -EEXIST; goto add_return; } #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) netlbl_af6list_foreach_rcu(iter6, &entry->type_def.addrsel->list6) if (netlbl_af6list_search_exact(&iter6->addr, &iter6->mask, old_list6)) { ret_val = -EEXIST; goto add_return; } #endif /* IPv6 */ netlbl_af4list_foreach_safe(iter4, tmp4, &entry->type_def.addrsel->list4) { netlbl_af4list_remove_entry(iter4); iter4->valid = 1; ret_val = netlbl_af4list_add(iter4, old_list4); netlbl_domhsh_audit_add(entry_old, iter4, NULL, ret_val, audit_info); if (ret_val != 0) goto add_return; } #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) netlbl_af6list_foreach_safe(iter6, tmp6, &entry->type_def.addrsel->list6) { netlbl_af6list_remove_entry(iter6); iter6->valid = 1; ret_val = netlbl_af6list_add(iter6, old_list6); netlbl_domhsh_audit_add(entry_old, NULL, iter6, ret_val, audit_info); if (ret_val != 0) goto add_return; } #endif /* IPv6 */ } else ret_val = -EINVAL; add_return: spin_unlock(&netlbl_domhsh_lock); rcu_read_unlock(); return ret_val; } /** * netlbl_domhsh_add_default - Adds the default entry to the domain hash table * @entry: the entry to add * @audit_info: NetLabel audit information * * Description: * Adds a new default entry to the domain hash table and handles any updates * to the lower level protocol handler (i.e. CIPSO). Returns zero on success, * negative on failure. * */ int netlbl_domhsh_add_default(struct netlbl_dom_map *entry, struct netlbl_audit *audit_info) { return netlbl_domhsh_add(entry, audit_info); } /** * netlbl_domhsh_remove_entry - Removes a given entry from the domain table * @entry: the entry to remove * @audit_info: NetLabel audit information * * Description: * Removes an entry from the domain hash table and handles any updates to the * lower level protocol handler (i.e. CIPSO). Caller is responsible for * ensuring that the RCU read lock is held. Returns zero on success, negative * on failure. * */ int netlbl_domhsh_remove_entry(struct netlbl_dom_map *entry, struct netlbl_audit *audit_info) { int ret_val = 0; struct audit_buffer *audit_buf; if (entry == NULL) return -ENOENT; spin_lock(&netlbl_domhsh_lock); if (entry->valid) { entry->valid = 0; if (entry != rcu_dereference(netlbl_domhsh_def)) list_del_rcu(&entry->list); else RCU_INIT_POINTER(netlbl_domhsh_def, NULL); } else ret_val = -ENOENT; spin_unlock(&netlbl_domhsh_lock); audit_buf = netlbl_audit_start_common(AUDIT_MAC_MAP_DEL, audit_info); if (audit_buf != NULL) { audit_log_format(audit_buf, " nlbl_domain=%s res=%u", entry->domain ? entry->domain : "(default)", ret_val == 0 ? 1 : 0); audit_log_end(audit_buf); } if (ret_val == 0) { struct netlbl_af4list *iter4; struct netlbl_domaddr4_map *map4; switch (entry->type) { case NETLBL_NLTYPE_ADDRSELECT: netlbl_af4list_foreach_rcu(iter4, &entry->type_def.addrsel->list4) { map4 = netlbl_domhsh_addr4_entry(iter4); cipso_v4_doi_putdef(map4->type_def.cipsov4); } /* no need to check the IPv6 list since we currently * support only unlabeled protocols for IPv6 */ break; case NETLBL_NLTYPE_CIPSOV4: cipso_v4_doi_putdef(entry->type_def.cipsov4); break; } call_rcu(&entry->rcu, netlbl_domhsh_free_entry); } return ret_val; } /** * netlbl_domhsh_remove_af4 - Removes an address selector entry * @domain: the domain * @addr: IPv4 address * @mask: IPv4 address mask * @audit_info: NetLabel audit information * * Description: * Removes an individual address selector from a domain mapping and potentially * the entire mapping if it is empty. Returns zero on success, negative values * on failure. * */ int netlbl_domhsh_remove_af4(const char *domain, const struct in_addr *addr, const struct in_addr *mask, struct netlbl_audit *audit_info) { struct netlbl_dom_map *entry_map; struct netlbl_af4list *entry_addr; struct netlbl_af4list *iter4; #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) struct netlbl_af6list *iter6; #endif /* IPv6 */ struct netlbl_domaddr4_map *entry; rcu_read_lock(); if (domain) entry_map = netlbl_domhsh_search(domain); else entry_map = netlbl_domhsh_search_def(domain); if (entry_map == NULL || entry_map->type != NETLBL_NLTYPE_ADDRSELECT) goto remove_af4_failure; spin_lock(&netlbl_domhsh_lock); entry_addr = netlbl_af4list_remove(addr->s_addr, mask->s_addr, &entry_map->type_def.addrsel->list4); spin_unlock(&netlbl_domhsh_lock); if (entry_addr == NULL) goto remove_af4_failure; netlbl_af4list_foreach_rcu(iter4, &entry_map->type_def.addrsel->list4) goto remove_af4_single_addr; #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) netlbl_af6list_foreach_rcu(iter6, &entry_map->type_def.addrsel->list6) goto remove_af4_single_addr; #endif /* IPv6 */ /* the domain mapping is empty so remove it from the mapping table */ netlbl_domhsh_remove_entry(entry_map, audit_info); remove_af4_single_addr: rcu_read_unlock(); /* yick, we can't use call_rcu here because we don't have a rcu head * pointer but hopefully this should be a rare case so the pause * shouldn't be a problem */ synchronize_rcu(); entry = netlbl_domhsh_addr4_entry(entry_addr); cipso_v4_doi_putdef(entry->type_def.cipsov4); kfree(entry); return 0; remove_af4_failure: rcu_read_unlock(); return -ENOENT; } /** * netlbl_domhsh_remove - Removes an entry from the domain hash table * @domain: the domain to remove * @audit_info: NetLabel audit information * * Description: * Removes an entry from the domain hash table and handles any updates to the * lower level protocol handler (i.e. CIPSO). Returns zero on success, * negative on failure. * */ int netlbl_domhsh_remove(const char *domain, struct netlbl_audit *audit_info) { int ret_val; struct netlbl_dom_map *entry; rcu_read_lock(); if (domain) entry = netlbl_domhsh_search(domain); else entry = netlbl_domhsh_search_def(domain); ret_val = netlbl_domhsh_remove_entry(entry, audit_info); rcu_read_unlock(); return ret_val; } /** * netlbl_domhsh_remove_default - Removes the default entry from the table * @audit_info: NetLabel audit information * * Description: * Removes/resets the default entry for the domain hash table and handles any * updates to the lower level protocol handler (i.e. CIPSO). Returns zero on * success, non-zero on failure. * */ int netlbl_domhsh_remove_default(struct netlbl_audit *audit_info) { return netlbl_domhsh_remove(NULL, audit_info); } /** * netlbl_domhsh_getentry - Get an entry from the domain hash table * @domain: the domain name to search for * * Description: * Look through the domain hash table searching for an entry to match @domain, * return a pointer to a copy of the entry or NULL. The caller is responsible * for ensuring that rcu_read_[un]lock() is called. * */ struct netlbl_dom_map *netlbl_domhsh_getentry(const char *domain) { return netlbl_domhsh_search_def(domain); } /** * netlbl_domhsh_getentry_af4 - Get an entry from the domain hash table * @domain: the domain name to search for * @addr: the IP address to search for * * Description: * Look through the domain hash table searching for an entry to match @domain * and @addr, return a pointer to a copy of the entry or NULL. The caller is * responsible for ensuring that rcu_read_[un]lock() is called. * */ struct netlbl_domaddr4_map *netlbl_domhsh_getentry_af4(const char *domain, __be32 addr) { struct netlbl_dom_map *dom_iter; struct netlbl_af4list *addr_iter; dom_iter = netlbl_domhsh_search_def(domain); if (dom_iter == NULL) return NULL; if (dom_iter->type != NETLBL_NLTYPE_ADDRSELECT) return NULL; addr_iter = netlbl_af4list_search(addr, &dom_iter->type_def.addrsel->list4); if (addr_iter == NULL) return NULL; return netlbl_domhsh_addr4_entry(addr_iter); } #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) /** * netlbl_domhsh_getentry_af6 - Get an entry from the domain hash table * @domain: the domain name to search for * @addr: the IP address to search for * * Description: * Look through the domain hash table searching for an entry to match @domain * and @addr, return a pointer to a copy of the entry or NULL. The caller is * responsible for ensuring that rcu_read_[un]lock() is called. * */ struct netlbl_domaddr6_map *netlbl_domhsh_getentry_af6(const char *domain, const struct in6_addr *addr) { struct netlbl_dom_map *dom_iter; struct netlbl_af6list *addr_iter; dom_iter = netlbl_domhsh_search_def(domain); if (dom_iter == NULL) return NULL; if (dom_iter->type != NETLBL_NLTYPE_ADDRSELECT) return NULL; addr_iter = netlbl_af6list_search(addr, &dom_iter->type_def.addrsel->list6); if (addr_iter == NULL) return NULL; return netlbl_domhsh_addr6_entry(addr_iter); } #endif /* IPv6 */ /** * netlbl_domhsh_walk - Iterate through the domain mapping hash table * @skip_bkt: the number of buckets to skip at the start * @skip_chain: the number of entries to skip in the first iterated bucket * @callback: callback for each entry * @cb_arg: argument for the callback function * * Description: * Interate over the domain mapping hash table, skipping the first @skip_bkt * buckets and @skip_chain entries. For each entry in the table call * @callback, if @callback returns a negative value stop 'walking' through the * table and return. Updates the values in @skip_bkt and @skip_chain on * return. Returns zero on success, negative values on failure. * */ int netlbl_domhsh_walk(u32 *skip_bkt, u32 *skip_chain, int (*callback) (struct netlbl_dom_map *entry, void *arg), void *cb_arg) { int ret_val = -ENOENT; u32 iter_bkt; struct list_head *iter_list; struct netlbl_dom_map *iter_entry; u32 chain_cnt = 0; rcu_read_lock(); for (iter_bkt = *skip_bkt; iter_bkt < rcu_dereference(netlbl_domhsh)->size; iter_bkt++, chain_cnt = 0) { iter_list = &rcu_dereference(netlbl_domhsh)->tbl[iter_bkt]; list_for_each_entry_rcu(iter_entry, iter_list, list) if (iter_entry->valid) { if (chain_cnt++ < *skip_chain) continue; ret_val = callback(iter_entry, cb_arg); if (ret_val < 0) { chain_cnt--; goto walk_return; } } } walk_return: rcu_read_unlock(); *skip_bkt = iter_bkt; *skip_chain = chain_cnt; return ret_val; }