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237 lines
5.6 KiB
237 lines
5.6 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Pkey table |
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* |
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* SELinux must keep a mapping of Infinband PKEYs to labels/SIDs. This |
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* mapping is maintained as part of the normal policy but a fast cache is |
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* needed to reduce the lookup overhead. |
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* |
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* This code is heavily based on the "netif" and "netport" concept originally |
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* developed by |
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* James Morris <[email protected]> and |
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* Paul Moore <[email protected]> |
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* (see security/selinux/netif.c and security/selinux/netport.c for more |
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* information) |
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*/ |
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/* |
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* (c) Mellanox Technologies, 2016 |
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*/ |
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#include <linux/types.h> |
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#include <linux/rcupdate.h> |
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#include <linux/list.h> |
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#include <linux/spinlock.h> |
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#include "ibpkey.h" |
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#include "objsec.h" |
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#define SEL_PKEY_HASH_SIZE 256 |
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#define SEL_PKEY_HASH_BKT_LIMIT 16 |
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struct sel_ib_pkey_bkt { |
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int size; |
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struct list_head list; |
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}; |
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struct sel_ib_pkey { |
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struct pkey_security_struct psec; |
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struct list_head list; |
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struct rcu_head rcu; |
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}; |
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static DEFINE_SPINLOCK(sel_ib_pkey_lock); |
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static struct sel_ib_pkey_bkt sel_ib_pkey_hash[SEL_PKEY_HASH_SIZE]; |
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/** |
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* sel_ib_pkey_hashfn - Hashing function for the pkey table |
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* @pkey: pkey number |
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* |
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* Description: |
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* This is the hashing function for the pkey table, it returns the bucket |
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* number for the given pkey. |
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* |
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*/ |
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static unsigned int sel_ib_pkey_hashfn(u16 pkey) |
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{ |
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return (pkey & (SEL_PKEY_HASH_SIZE - 1)); |
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} |
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/** |
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* sel_ib_pkey_find - Search for a pkey record |
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* @subnet_prefix: subnet_prefix |
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* @pkey_num: pkey_num |
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* |
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* Description: |
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* Search the pkey table and return the matching record. If an entry |
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* can not be found in the table return NULL. |
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* |
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*/ |
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static struct sel_ib_pkey *sel_ib_pkey_find(u64 subnet_prefix, u16 pkey_num) |
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{ |
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unsigned int idx; |
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struct sel_ib_pkey *pkey; |
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idx = sel_ib_pkey_hashfn(pkey_num); |
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list_for_each_entry_rcu(pkey, &sel_ib_pkey_hash[idx].list, list) { |
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if (pkey->psec.pkey == pkey_num && |
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pkey->psec.subnet_prefix == subnet_prefix) |
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return pkey; |
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} |
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return NULL; |
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} |
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/** |
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* sel_ib_pkey_insert - Insert a new pkey into the table |
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* @pkey: the new pkey record |
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* |
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* Description: |
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* Add a new pkey record to the hash table. |
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* |
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*/ |
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static void sel_ib_pkey_insert(struct sel_ib_pkey *pkey) |
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{ |
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unsigned int idx; |
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/* we need to impose a limit on the growth of the hash table so check |
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* this bucket to make sure it is within the specified bounds |
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*/ |
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idx = sel_ib_pkey_hashfn(pkey->psec.pkey); |
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list_add_rcu(&pkey->list, &sel_ib_pkey_hash[idx].list); |
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if (sel_ib_pkey_hash[idx].size == SEL_PKEY_HASH_BKT_LIMIT) { |
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struct sel_ib_pkey *tail; |
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tail = list_entry( |
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rcu_dereference_protected( |
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list_tail_rcu(&sel_ib_pkey_hash[idx].list), |
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lockdep_is_held(&sel_ib_pkey_lock)), |
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struct sel_ib_pkey, list); |
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list_del_rcu(&tail->list); |
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kfree_rcu(tail, rcu); |
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} else { |
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sel_ib_pkey_hash[idx].size++; |
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} |
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} |
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/** |
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* sel_ib_pkey_sid_slow - Lookup the SID of a pkey using the policy |
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* @subnet_prefix: subnet prefix |
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* @pkey_num: pkey number |
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* @sid: pkey SID |
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* |
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* Description: |
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* This function determines the SID of a pkey by querying the security |
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* policy. The result is added to the pkey table to speedup future |
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* queries. Returns zero on success, negative values on failure. |
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* |
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*/ |
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static int sel_ib_pkey_sid_slow(u64 subnet_prefix, u16 pkey_num, u32 *sid) |
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{ |
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int ret; |
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struct sel_ib_pkey *pkey; |
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struct sel_ib_pkey *new = NULL; |
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unsigned long flags; |
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spin_lock_irqsave(&sel_ib_pkey_lock, flags); |
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pkey = sel_ib_pkey_find(subnet_prefix, pkey_num); |
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if (pkey) { |
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*sid = pkey->psec.sid; |
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spin_unlock_irqrestore(&sel_ib_pkey_lock, flags); |
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return 0; |
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} |
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ret = security_ib_pkey_sid(&selinux_state, subnet_prefix, pkey_num, |
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sid); |
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if (ret) |
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goto out; |
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/* If this memory allocation fails still return 0. The SID |
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* is valid, it just won't be added to the cache. |
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*/ |
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new = kzalloc(sizeof(*new), GFP_ATOMIC); |
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if (!new) { |
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ret = -ENOMEM; |
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goto out; |
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} |
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new->psec.subnet_prefix = subnet_prefix; |
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new->psec.pkey = pkey_num; |
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new->psec.sid = *sid; |
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sel_ib_pkey_insert(new); |
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out: |
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spin_unlock_irqrestore(&sel_ib_pkey_lock, flags); |
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return ret; |
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} |
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/** |
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* sel_ib_pkey_sid - Lookup the SID of a PKEY |
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* @subnet_prefix: subnet_prefix |
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* @pkey_num: pkey number |
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* @sid: pkey SID |
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* |
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* Description: |
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* This function determines the SID of a PKEY using the fastest method |
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* possible. First the pkey table is queried, but if an entry can't be found |
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* then the policy is queried and the result is added to the table to speedup |
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* future queries. Returns zero on success, negative values on failure. |
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* |
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*/ |
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int sel_ib_pkey_sid(u64 subnet_prefix, u16 pkey_num, u32 *sid) |
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{ |
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struct sel_ib_pkey *pkey; |
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rcu_read_lock(); |
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pkey = sel_ib_pkey_find(subnet_prefix, pkey_num); |
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if (pkey) { |
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*sid = pkey->psec.sid; |
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rcu_read_unlock(); |
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return 0; |
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} |
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rcu_read_unlock(); |
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return sel_ib_pkey_sid_slow(subnet_prefix, pkey_num, sid); |
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} |
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/** |
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* sel_ib_pkey_flush - Flush the entire pkey table |
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* |
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* Description: |
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* Remove all entries from the pkey table |
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* |
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*/ |
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void sel_ib_pkey_flush(void) |
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{ |
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unsigned int idx; |
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struct sel_ib_pkey *pkey, *pkey_tmp; |
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unsigned long flags; |
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spin_lock_irqsave(&sel_ib_pkey_lock, flags); |
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for (idx = 0; idx < SEL_PKEY_HASH_SIZE; idx++) { |
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list_for_each_entry_safe(pkey, pkey_tmp, |
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&sel_ib_pkey_hash[idx].list, list) { |
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list_del_rcu(&pkey->list); |
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kfree_rcu(pkey, rcu); |
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} |
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sel_ib_pkey_hash[idx].size = 0; |
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} |
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spin_unlock_irqrestore(&sel_ib_pkey_lock, flags); |
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} |
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static __init int sel_ib_pkey_init(void) |
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{ |
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int iter; |
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if (!selinux_enabled_boot) |
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return 0; |
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for (iter = 0; iter < SEL_PKEY_HASH_SIZE; iter++) { |
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INIT_LIST_HEAD(&sel_ib_pkey_hash[iter].list); |
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sel_ib_pkey_hash[iter].size = 0; |
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} |
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return 0; |
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} |
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subsys_initcall(sel_ib_pkey_init);
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