--- /dev/null
+/*
+ * 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 <jmorris@redhat.com> and
+ * Paul Moore <paul@paul-moore.com>
+ * (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 <linux/types.h>
+#include <linux/rcupdate.h>
+#include <linux/list.h>
+#include <linux/spinlock.h>
+
+#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(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);
projects / users / dwmw2 / linux.git / commitdiff