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/*
* 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, see <http://www.gnu.org/licenses/>.
*
*/
#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->def.type == NETLBL_NLTYPE_ADDRSELECT) {
netlbl_af4list_foreach_safe(iter4, tmp4,
&ptr->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->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->def.type;
cipsov4 = map4->def.cipso;
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->def.type;
netlbl_af6list_audit_addr(audit_buf, 0, NULL,
&addr6->addr, &addr6->mask);
#endif /* IPv6 */
} else {
type = entry->def.type;
|