1 files changed, 237 insertions, 0 deletions
diff --git a/security/selinux/ibpkey.c b/security/selinux/ibpkey.c
new file mode 100644
index 000000000..5839ca7bb
--- /dev/null
+++ b/security/selinux/ibpkey.c
@@ -0,0 +1,237 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * 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
+ */
+
+#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 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(
+				list_tail_rcu(&sel_ib_pkey_hash[idx].list),
+				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) {
+		ret = -ENOMEM;
+		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_boot)
+		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);