/* * Pkey table * * SELinux must keep a mapping of Infinband PKEYs to labels/SIDs. This * mapping is maintained as part of the normal policy but a fast cache is * needed to reduce the lookup overhead. * * This code is heavily based on the "netif" and "netport" concept originally * developed by * James Morris and * Paul Moore * (see security/selinux/netif.c and security/selinux/netport.c for more * information) * */ /* * (c) Mellanox Technologies, 2016 * * This program is free software: you can redistribute it and/or modify * it under the terms of version 2 of the GNU General Public License as * published by the Free Software Foundation. * * 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. * */ #include #include #include #include #include "ibpkey.h" #include "objsec.h" #define SEL_PKEY_HASH_SIZE 256 #define SEL_PKEY_HASH_BKT_LIMIT 16 struct sel_ib_pkey_bkt { int size; struct list_head list; }; struct sel_ib_pkey { struct pkey_security_struct psec; struct list_head list; struct rcu_head rcu; }; static LIST_HEAD(sel_ib_pkey_list); static DEFINE_SPINLOCK(sel_ib_pkey_lock); static struct sel_ib_pkey_bkt sel_ib_pkey_hash[SEL_PKEY_HASH_SIZE]; /** * sel_ib_pkey_hashfn - Hashing function for the pkey table * @pkey: pkey number * * Description: * This is the hashing function for the pkey table, it returns the bucket * number for the given pkey. * */ static unsigned int sel_ib_pkey_hashfn(u16 pkey) { return (pkey & (SEL_PKEY_HASH_SIZE - 1)); } /** * sel_ib_pkey_find - Search for a pkey record * @subnet_prefix: subnet_prefix * @pkey_num: pkey_num * * Description: * Search the pkey table and return the matching record. If an entry * can not be found in the table return NULL. * */ static struct sel_ib_pkey *sel_ib_pkey_find(u64 subnet_prefix, u16 pkey_num) { unsigned int idx; struct sel_ib_pkey *pkey; idx = sel_ib_pkey_hashfn(pkey_num); list_for_each_entry_rcu(pkey, &sel_ib_pkey_hash[idx].list, list) { if (pkey->psec.pkey == pkey_num && pkey->psec.subnet_prefix == subnet_prefix) return pkey; } return NULL; } /** * sel_ib_pkey_insert - Insert a new pkey into the table * @pkey: the new pkey record * * Description: * Add a new pkey record to the hash table. * */ static void sel_ib_pkey_insert(struct sel_ib_pkey *pkey) { unsigned int idx; /* we need to impose a limit on the growth of the hash table so check * this bucket to make sure it is within the specified bounds */ idx = sel_ib_pkey_hashfn(pkey->psec.pkey); list_add_rcu(&pkey->list, &sel_ib_pkey_hash[idx].list); if (sel_ib_pkey_hash[idx].size == SEL_PKEY_HASH_BKT_LIMIT) { struct sel_ib_pkey *tail; tail = list_entry( rcu_dereference_protected( sel_ib_pkey_hash[idx].list.prev, lockdep_is_held(&sel_ib_pkey_lock)), struct sel_ib_pkey, list); list_del_rcu(&tail->list); kfree_rcu(tail, rcu); } else { sel_ib_pkey_hash[idx].size++; } } /** * sel_ib_pkey_sid_slow - Lookup the SID of a pkey using the policy * @subnet_prefix: subnet prefix * @pkey_num: pkey number * @sid: pkey SID * * Description: * This function determines the SID of a pkey by querying the security * policy. The result is added to the pkey table to speedup future * queries. Returns zero on success, negative values on failure. * */ static int sel_ib_pkey_sid_slow(u64 subnet_prefix, u16 pkey_num, u32 *sid) { int ret; struct sel_ib_pkey *pkey; struct sel_ib_pkey *new = NULL; unsigned long flags; spin_lock_irqsave(&sel_ib_pkey_lock, flags); pkey = sel_ib_pkey_find(subnet_prefix, pkey_num); if (pkey) { *sid = pkey->psec.sid; spin_unlock_irqrestore(&sel_ib_pkey_lock, flags); return 0; } ret = security_ib_pkey_sid(&selinux_state, subnet_prefix, pkey_num, sid); if (ret) goto out; /* If this memory allocation fails still return 0. The SID * is valid, it just won't be added to the cache. */ new = kzalloc(sizeof(*new), GFP_ATOMIC); if (!new) goto out; new->psec.subnet_prefix = subnet_prefix; new->psec.pkey = pkey_num; new->psec.sid = *sid; sel_ib_pkey_insert(new); out: spin_unlock_irqrestore(&sel_ib_pkey_lock, flags); return ret; } /** * sel_ib_pkey_sid - Lookup the SID of a PKEY * @subnet_prefix: subnet_prefix * @pkey_num: pkey number * @sid: pkey SID * * Description: * This function determines the SID of a PKEY using the fastest method * possible. First the pkey table is queried, but if an entry can't be found * then the policy is queried and the result is added to the table to speedup * future queries. Returns zero on success, negative values on failure. * */ int sel_ib_pkey_sid(u64 subnet_prefix, u16 pkey_num, u32 *sid) { struct sel_ib_pkey *pkey; rcu_read_lock(); pkey = sel_ib_pkey_find(subnet_prefix, pkey_num); if (pkey) { *sid = pkey->psec.sid; rcu_read_unlock(); return 0; } rcu_read_unlock(); return sel_ib_pkey_sid_slow(subnet_prefix, pkey_num, sid); } /** * sel_ib_pkey_flush - Flush the entire pkey table * * Description: * Remove all entries from the pkey table * */ void sel_ib_pkey_flush(void) { unsigned int idx; struct sel_ib_pkey *pkey, *pkey_tmp; unsigned long flags; spin_lock_irqsave(&sel_ib_pkey_lock, flags); for (idx = 0; idx < SEL_PKEY_HASH_SIZE; idx++) { list_for_each_entry_safe(pkey, pkey_tmp, &sel_ib_pkey_hash[idx].list, list) { list_del_rcu(&pkey->list); kfree_rcu(pkey, rcu); } sel_ib_pkey_hash[idx].size = 0; } spin_unlock_irqrestore(&sel_ib_pkey_lock, flags); } static __init int sel_ib_pkey_init(void) { int iter; if (!selinux_enabled) return 0; for (iter = 0; iter < SEL_PKEY_HASH_SIZE; iter++) { INIT_LIST_HEAD(&sel_ib_pkey_hash[iter].list); sel_ib_pkey_hash[iter].size = 0; } return 0; } subsys_initcall(sel_ib_pkey_init);