- 根目录:
- net
- netlabel
- netlabel_domainhash.c
/*
* 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;
}