--- /dev/null
+/*
+ * Network node table
+ *
+ * SELinux must keep a mapping of network nodes to labels/SIDs. This
+ * mapping is maintained as part of the normal policy but a fast cache is
+ * needed to reduce the lookup overhead since most of these queries happen on
+ * a per-packet basis.
+ *
+ * Author: Paul Moore <paul@paul-moore.com>
+ *
+ * This code is heavily based on the "netif" concept originally developed by
+ * James Morris <jmorris@redhat.com>
+ * (see security/selinux/netif.c for more information)
+ *
+ */
+
+/*
+ * (c) Copyright Hewlett-Packard Development Company, L.P., 2007
+ *
+ * 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/slab.h>
+#include <linux/spinlock.h>
+#include <linux/in.h>
+#include <linux/in6.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include <net/ip.h>
+#include <net/ipv6.h>
+
+#include "netnode.h"
+#include "objsec.h"
+
+#define SEL_NETNODE_HASH_SIZE 256
+#define SEL_NETNODE_HASH_BKT_LIMIT 16
+
+struct sel_netnode_bkt {
+ unsigned int size;
+ struct list_head list;
+};
+
+struct sel_netnode {
+ struct netnode_security_struct nsec;
+
+ struct list_head list;
+ struct rcu_head rcu;
+};
+
+/* NOTE: we are using a combined hash table for both IPv4 and IPv6, the reason
+ * for this is that I suspect most users will not make heavy use of both
+ * address families at the same time so one table will usually end up wasted,
+ * if this becomes a problem we can always add a hash table for each address
+ * family later */
+
+static LIST_HEAD(sel_netnode_list);
+static DEFINE_SPINLOCK(sel_netnode_lock);
+static struct sel_netnode_bkt sel_netnode_hash[SEL_NETNODE_HASH_SIZE];
+
+/**
+ * sel_netnode_hashfn_ipv4 - IPv4 hashing function for the node table
+ * @addr: IPv4 address
+ *
+ * Description:
+ * This is the IPv4 hashing function for the node interface table, it returns
+ * the bucket number for the given IP address.
+ *
+ */
+static unsigned int sel_netnode_hashfn_ipv4(__be32 addr)
+{
+ /* at some point we should determine if the mismatch in byte order
+ * affects the hash function dramatically */
+ return (addr & (SEL_NETNODE_HASH_SIZE - 1));
+}
+
+/**
+ * sel_netnode_hashfn_ipv6 - IPv6 hashing function for the node table
+ * @addr: IPv6 address
+ *
+ * Description:
+ * This is the IPv6 hashing function for the node interface table, it returns
+ * the bucket number for the given IP address.
+ *
+ */
+static unsigned int sel_netnode_hashfn_ipv6(const struct in6_addr *addr)
+{
+ /* just hash the least significant 32 bits to keep things fast (they
+ * are the most likely to be different anyway), we can revisit this
+ * later if needed */
+ return (addr->s6_addr32[3] & (SEL_NETNODE_HASH_SIZE - 1));
+}
+
+/**
+ * sel_netnode_find - Search for a node record
+ * @addr: IP address
+ * @family: address family
+ *
+ * Description:
+ * Search the network node table and return the record matching @addr. If an
+ * entry can not be found in the table return NULL.
+ *
+ */
+static struct sel_netnode *sel_netnode_find(const void *addr, u16 family)
+{
+ unsigned int idx;
+ struct sel_netnode *node;
+
+ switch (family) {
+ case PF_INET:
+ idx = sel_netnode_hashfn_ipv4(*(__be32 *)addr);
+ break;
+ case PF_INET6:
+ idx = sel_netnode_hashfn_ipv6(addr);
+ break;
+ default:
+ BUG();
+ return NULL;
+ }
+
+ list_for_each_entry_rcu(node, &sel_netnode_hash[idx].list, list)
+ if (node->nsec.family == family)
+ switch (family) {
+ case PF_INET:
+ if (node->nsec.addr.ipv4 == *(__be32 *)addr)
+ return node;
+ break;
+ case PF_INET6:
+ if (ipv6_addr_equal(&node->nsec.addr.ipv6,
+ addr))
+ return node;
+ break;
+ }
+
+ return NULL;
+}
+
+/**
+ * sel_netnode_insert - Insert a new node into the table
+ * @node: the new node record
+ *
+ * Description:
+ * Add a new node record to the network address hash table.
+ *
+ */
+static void sel_netnode_insert(struct sel_netnode *node)
+{
+ unsigned int idx;
+
+ switch (node->nsec.family) {
+ case PF_INET:
+ idx = sel_netnode_hashfn_ipv4(node->nsec.addr.ipv4);
+ break;
+ case PF_INET6:
+ idx = sel_netnode_hashfn_ipv6(&node->nsec.addr.ipv6);
+ break;
+ default:
+ BUG();
+ return;
+ }
+
+ /* 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 */
+ list_add_rcu(&node->list, &sel_netnode_hash[idx].list);
+ if (sel_netnode_hash[idx].size == SEL_NETNODE_HASH_BKT_LIMIT) {
+ struct sel_netnode *tail;
+ tail = list_entry(
+ rcu_dereference_protected(sel_netnode_hash[idx].list.prev,
+ lockdep_is_held(&sel_netnode_lock)),
+ struct sel_netnode, list);
+ list_del_rcu(&tail->list);
+ kfree_rcu(tail, rcu);
+ } else
+ sel_netnode_hash[idx].size++;
+}
+
+/**
+ * sel_netnode_sid_slow - Lookup the SID of a network address using the policy
+ * @addr: the IP address
+ * @family: the address family
+ * @sid: node SID
+ *
+ * Description:
+ * This function determines the SID of a network address by quering the
+ * security policy. The result is added to the network address table to
+ * speedup future queries. Returns zero on success, negative values on
+ * failure.
+ *
+ */
+static int sel_netnode_sid_slow(void *addr, u16 family, u32 *sid)
+{
+ int ret = -ENOMEM;
+ struct sel_netnode *node;
+ struct sel_netnode *new = NULL;
+
+ spin_lock_bh(&sel_netnode_lock);
+ node = sel_netnode_find(addr, family);
+ if (node != NULL) {
+ *sid = node->nsec.sid;
+ spin_unlock_bh(&sel_netnode_lock);
+ return 0;
+ }
+ new = kzalloc(sizeof(*new), GFP_ATOMIC);
+ if (new == NULL)
+ goto out;
+ switch (family) {
+ case PF_INET:
+ ret = security_node_sid(PF_INET,
+ addr, sizeof(struct in_addr), sid);
+ new->nsec.addr.ipv4 = *(__be32 *)addr;
+ break;
+ case PF_INET6:
+ ret = security_node_sid(PF_INET6,
+ addr, sizeof(struct in6_addr), sid);
+ new->nsec.addr.ipv6 = *(struct in6_addr *)addr;
+ break;
+ default:
+ BUG();
+ ret = -EINVAL;
+ }
+ if (ret != 0)
+ goto out;
+
+ new->nsec.family = family;
+ new->nsec.sid = *sid;
+ sel_netnode_insert(new);
+
+out:
+ spin_unlock_bh(&sel_netnode_lock);
+ if (unlikely(ret)) {
+ printk(KERN_WARNING
+ "SELinux: failure in sel_netnode_sid_slow(),"
+ " unable to determine network node label\n");
+ kfree(new);
+ }
+ return ret;
+}
+
+/**
+ * sel_netnode_sid - Lookup the SID of a network address
+ * @addr: the IP address
+ * @family: the address family
+ * @sid: node SID
+ *
+ * Description:
+ * This function determines the SID of a network address using the fastest
+ * method possible. First the address 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_netnode_sid(void *addr, u16 family, u32 *sid)
+{
+ struct sel_netnode *node;
+
+ rcu_read_lock();
+ node = sel_netnode_find(addr, family);
+ if (node != NULL) {
+ *sid = node->nsec.sid;
+ rcu_read_unlock();
+ return 0;
+ }
+ rcu_read_unlock();
+
+ return sel_netnode_sid_slow(addr, family, sid);
+}
+
+/**
+ * sel_netnode_flush - Flush the entire network address table
+ *
+ * Description:
+ * Remove all entries from the network address table.
+ *
+ */
+void sel_netnode_flush(void)
+{
+ unsigned int idx;
+ struct sel_netnode *node, *node_tmp;
+
+ spin_lock_bh(&sel_netnode_lock);
+ for (idx = 0; idx < SEL_NETNODE_HASH_SIZE; idx++) {
+ list_for_each_entry_safe(node, node_tmp,
+ &sel_netnode_hash[idx].list, list) {
+ list_del_rcu(&node->list);
+ kfree_rcu(node, rcu);
+ }
+ sel_netnode_hash[idx].size = 0;
+ }
+ spin_unlock_bh(&sel_netnode_lock);
+}
+
+static __init int sel_netnode_init(void)
+{
+ int iter;
+
+ if (!selinux_enabled)
+ return 0;
+
+ for (iter = 0; iter < SEL_NETNODE_HASH_SIZE; iter++) {
+ INIT_LIST_HEAD(&sel_netnode_hash[iter].list);
+ sel_netnode_hash[iter].size = 0;
+ }
+
+ return 0;
+}
+
+__initcall(sel_netnode_init);
Code Review / kvmfornfv.git / blobdiff