diff options
Diffstat (limited to 'net/netlabel/netlabel_domainhash.c')
| -rw-r--r-- | net/netlabel/netlabel_domainhash.c | 513 |
1 files changed, 513 insertions, 0 deletions
diff --git a/net/netlabel/netlabel_domainhash.c b/net/netlabel/netlabel_domainhash.c new file mode 100644 index 0000000..5bb3fad --- /dev/null +++ b/net/netlabel/netlabel_domainhash.c @@ -0,0 +1,513 @@ +/* + * 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.moore@hp.com> + * + */ + +/* + * (c) Copyright Hewlett-Packard Development Company, L.P., 2006 + * + * 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/rcupdate.h> +#include <linux/list.h> +#include <linux/skbuff.h> +#include <linux/spinlock.h> +#include <linux/string.h> +#include <net/netlabel.h> +#include <net/cipso_ipv4.h> +#include <asm/bug.h> + +#include "netlabel_mgmt.h" +#include "netlabel_domainhash.h" + +struct netlbl_domhsh_tbl { + struct list_head *tbl; + u32 size; +}; + +/* Domain hash table */ +/* XXX - updates should be so rare that having one spinlock for the entire + * hash table should be okay */ +DEFINE_SPINLOCK(netlbl_domhsh_lock); +static struct netlbl_domhsh_tbl *netlbl_domhsh = NULL; + +/* Default domain mapping */ +DEFINE_SPINLOCK(netlbl_domhsh_def_lock); +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; + + ptr = container_of(entry, struct netlbl_dom_map, rcu); + 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 responsibile for + * calling the rcu_read_[un]lock() functions. + * + */ +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 & (rcu_dereference(netlbl_domhsh)->size - 1); +} + +/** + * netlbl_domhsh_search - 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 found, otherwise NULL is returned. If @def is non-zero and a + * match is not found in the domain hash table the default mapping is returned + * if it exists. The caller is responsibile for the rcu hash table locks + * (i.e. the caller much call rcu_read_[un]lock()). + * + */ +static struct netlbl_dom_map *netlbl_domhsh_search(const char *domain, u32 def) +{ + u32 bkt; + struct netlbl_dom_map *iter; + + if (domain != NULL) { + bkt = netlbl_domhsh_hash(domain); + list_for_each_entry_rcu(iter, &netlbl_domhsh->tbl[bkt], list) + if (iter->valid && strcmp(iter->domain, domain) == 0) + return iter; + } + + if (def != 0) { + iter = rcu_dereference(netlbl_domhsh_def); + if (iter != NULL && iter->valid) + return iter; + } + + return NULL; +} + +/* + * 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 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]); + + rcu_read_lock(); + spin_lock(&netlbl_domhsh_lock); + rcu_assign_pointer(netlbl_domhsh, hsh_tbl); + spin_unlock(&netlbl_domhsh_lock); + rcu_read_unlock(); + + return 0; +} + +/** + * netlbl_domhsh_add - Adds a entry to the domain hash table + * @entry: the entry to add + * + * 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) +{ + int ret_val; + u32 bkt; + + switch (entry->type) { + case NETLBL_NLTYPE_UNLABELED: + ret_val = 0; + break; + case NETLBL_NLTYPE_CIPSOV4: + ret_val = cipso_v4_doi_domhsh_add(entry->type_def.cipsov4, + entry->domain); + break; + default: + return -EINVAL; + } + if (ret_val != 0) + return ret_val; + + entry->valid = 1; + INIT_RCU_HEAD(&entry->rcu); + + ret_val = 0; + rcu_read_lock(); + if (entry->domain != NULL) { + bkt = netlbl_domhsh_hash(entry->domain); + spin_lock(&netlbl_domhsh_lock); + if (netlbl_domhsh_search(entry->domain, 0) == NULL) + list_add_tail_rcu(&entry->list, + &netlbl_domhsh->tbl[bkt]); + else + ret_val = -EEXIST; + spin_unlock(&netlbl_domhsh_lock); + } else if (entry->domain == NULL) { + INIT_LIST_HEAD(&entry->list); + spin_lock(&netlbl_domhsh_def_lock); + if (rcu_dereference(netlbl_domhsh_def) == NULL) + rcu_assign_pointer(netlbl_domhsh_def, entry); + else + ret_val = -EEXIST; + spin_unlock(&netlbl_domhsh_def_lock); + } else + ret_val = -EINVAL; + rcu_read_unlock(); + + if (ret_val != 0) { + switch (entry->type) { + case NETLBL_NLTYPE_CIPSOV4: + if (cipso_v4_doi_domhsh_remove(entry->type_def.cipsov4, + entry->domain) != 0) + BUG(); + break; + } + } + + return ret_val; +} + +/** + * netlbl_domhsh_add_default - Adds the default entry to the domain hash table + * @entry: the entry to add + * + * 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) +{ + return netlbl_domhsh_add(entry); +} + +/** + * netlbl_domhsh_remove - Removes an entry from the domain hash table + * @domain: the domain to remove + * + * 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) +{ + int ret_val = -ENOENT; + struct netlbl_dom_map *entry; + + rcu_read_lock(); + if (domain != NULL) + entry = netlbl_domhsh_search(domain, 0); + else + entry = netlbl_domhsh_search(domain, 1); + if (entry == NULL) + goto remove_return; + switch (entry->type) { + case NETLBL_NLTYPE_UNLABELED: + break; + case NETLBL_NLTYPE_CIPSOV4: + ret_val = cipso_v4_doi_domhsh_remove(entry->type_def.cipsov4, + entry->domain); + if (ret_val != 0) + goto remove_return; + break; + } + ret_val = 0; + if (entry != rcu_dereference(netlbl_domhsh_def)) { + spin_lock(&netlbl_domhsh_lock); + if (entry->valid) { + entry->valid = 0; + list_del_rcu(&entry->list); + } else + ret_val = -ENOENT; + spin_unlock(&netlbl_domhsh_lock); + } else { + spin_lock(&netlbl_domhsh_def_lock); + if (entry->valid) { + entry->valid = 0; + rcu_assign_pointer(netlbl_domhsh_def, NULL); + } else + ret_val = -ENOENT; + spin_unlock(&netlbl_domhsh_def_lock); + } + if (ret_val == 0) + call_rcu(&entry->rcu, netlbl_domhsh_free_entry); + +remove_return: + rcu_read_unlock(); + return ret_val; +} + +/** + * netlbl_domhsh_remove_default - Removes the default entry from the table + * + * 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(void) +{ + return netlbl_domhsh_remove(NULL); +} + +/** + * 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 responsibile + * for ensuring that rcu_read_[un]lock() is called. + * + */ +struct netlbl_dom_map *netlbl_domhsh_getentry(const char *domain) +{ + return netlbl_domhsh_search(domain, 1); +} + +/** + * netlbl_domhsh_dump - Dump the domain hash table into a sk_buff + * + * Description: + * Dump the domain hash table into a buffer suitable for returning to an + * application in response to a NetLabel management DOMAIN message. This + * function may fail if another process is growing the hash table at the same + * time. The returned sk_buff has room at the front of the sk_buff for + * @headroom bytes. See netlabel.h for the DOMAIN message format. Returns a + * pointer to a sk_buff on success, NULL on error. + * + */ +struct sk_buff *netlbl_domhsh_dump(size_t headroom) +{ + struct sk_buff *skb = NULL; + ssize_t buf_len; + u32 bkt_iter; + u32 dom_cnt = 0; + struct netlbl_domhsh_tbl *hsh_tbl; + struct netlbl_dom_map *list_iter; + ssize_t tmp_len; + + buf_len = NETLBL_LEN_U32; + rcu_read_lock(); + hsh_tbl = rcu_dereference(netlbl_domhsh); + for (bkt_iter = 0; bkt_iter < hsh_tbl->size; bkt_iter++) + list_for_each_entry_rcu(list_iter, + &hsh_tbl->tbl[bkt_iter], list) { + buf_len += NETLBL_LEN_U32 + + nla_total_size(strlen(list_iter->domain) + 1); + switch (list_iter->type) { + case NETLBL_NLTYPE_UNLABELED: + break; + case NETLBL_NLTYPE_CIPSOV4: + buf_len += 2 * NETLBL_LEN_U32; + break; + } + dom_cnt++; + } + + skb = netlbl_netlink_alloc_skb(headroom, buf_len, GFP_ATOMIC); + if (skb == NULL) + goto dump_failure; + + if (nla_put_u32(skb, NLA_U32, dom_cnt) != 0) + goto dump_failure; + buf_len -= NETLBL_LEN_U32; + hsh_tbl = rcu_dereference(netlbl_domhsh); + for (bkt_iter = 0; bkt_iter < hsh_tbl->size; bkt_iter++) + list_for_each_entry_rcu(list_iter, + &hsh_tbl->tbl[bkt_iter], list) { + tmp_len = nla_total_size(strlen(list_iter->domain) + + 1); + if (buf_len < NETLBL_LEN_U32 + tmp_len) + goto dump_failure; + if (nla_put_string(skb, + NLA_STRING, + list_iter->domain) != 0) + goto dump_failure; + if (nla_put_u32(skb, NLA_U32, list_iter->type) != 0) + goto dump_failure; + buf_len -= NETLBL_LEN_U32 + tmp_len; + switch (list_iter->type) { + case NETLBL_NLTYPE_UNLABELED: + break; + case NETLBL_NLTYPE_CIPSOV4: + if (buf_len < 2 * NETLBL_LEN_U32) + goto dump_failure; + if (nla_put_u32(skb, + NLA_U32, + list_iter->type_def.cipsov4->type) != 0) + goto dump_failure; + if (nla_put_u32(skb, + NLA_U32, + list_iter->type_def.cipsov4->doi) != 0) + goto dump_failure; + buf_len -= 2 * NETLBL_LEN_U32; + break; + } + } + rcu_read_unlock(); + + return skb; + +dump_failure: + rcu_read_unlock(); + kfree_skb(skb); + return NULL; +} + +/** + * netlbl_domhsh_dump_default - Dump the default domain mapping into a sk_buff + * + * Description: + * Dump the default domain mapping into a buffer suitable for returning to an + * application in response to a NetLabel management DEFDOMAIN message. This + * function may fail if another process is changing the default domain mapping + * at the same time. The returned sk_buff has room at the front of the + * skb_buff for @headroom bytes. See netlabel.h for the DEFDOMAIN message + * format. Returns a pointer to a sk_buff on success, NULL on error. + * + */ +struct sk_buff *netlbl_domhsh_dump_default(size_t headroom) +{ + struct sk_buff *skb; + ssize_t buf_len; + struct netlbl_dom_map *entry; + + buf_len = NETLBL_LEN_U32; + rcu_read_lock(); + entry = rcu_dereference(netlbl_domhsh_def); + if (entry != NULL) + switch (entry->type) { + case NETLBL_NLTYPE_UNLABELED: + break; + case NETLBL_NLTYPE_CIPSOV4: + buf_len += 2 * NETLBL_LEN_U32; + break; + } + + skb = netlbl_netlink_alloc_skb(headroom, buf_len, GFP_ATOMIC); + if (skb == NULL) + goto dump_default_failure; + + if (entry != rcu_dereference(netlbl_domhsh_def)) + goto dump_default_failure; + if (entry != NULL) { + if (nla_put_u32(skb, NLA_U32, entry->type) != 0) + goto dump_default_failure; + buf_len -= NETLBL_LEN_U32; + switch (entry->type) { + case NETLBL_NLTYPE_UNLABELED: + break; + case NETLBL_NLTYPE_CIPSOV4: + if (buf_len < 2 * NETLBL_LEN_U32) + goto dump_default_failure; + if (nla_put_u32(skb, + NLA_U32, + entry->type_def.cipsov4->type) != 0) + goto dump_default_failure; + if (nla_put_u32(skb, + NLA_U32, + entry->type_def.cipsov4->doi) != 0) + goto dump_default_failure; + buf_len -= 2 * NETLBL_LEN_U32; + break; + } + } else + nla_put_u32(skb, NLA_U32, NETLBL_NLTYPE_NONE); + rcu_read_unlock(); + + return skb; + +dump_default_failure: + rcu_read_unlock(); + kfree_skb(skb); + return NULL; +} |