diff options
Diffstat (limited to 'net/netlabel/netlabel_domainhash.c')
| -rw-r--r-- | net/netlabel/netlabel_domainhash.c | 728 |
1 files changed, 728 insertions, 0 deletions
diff --git a/net/netlabel/netlabel_domainhash.c b/net/netlabel/netlabel_domainhash.c new file mode 100644 index 00000000..d8d42433 --- /dev/null +++ b/net/netlabel/netlabel_domainhash.c @@ -0,0 +1,728 @@ +/* + * 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 IS_ENABLED(CONFIG_IPV6) + 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 IS_ENABLED(CONFIG_IPV6) + 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 IS_ENABLED(CONFIG_IPV6) + } 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_assign_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 IS_ENABLED(CONFIG_IPV6) + 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_assign_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 IS_ENABLED(CONFIG_IPV6) + 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 IS_ENABLED(CONFIG_IPV6) + 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 IS_ENABLED(CONFIG_IPV6) + 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 IS_ENABLED(CONFIG_IPV6) + 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 IS_ENABLED(CONFIG_IPV6) + 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 IS_ENABLED(CONFIG_IPV6) +/** + * 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; +} |