SELinux: Convert the netif code to use ifindex values
The current SELinux netif code requires the caller have a valid net_device
struct pointer to lookup network interface information. However, we don't
always have a valid net_device pointer so convert the netif code to use
the ifindex values we always have as part of the sk_buff. This patch also
removes the default message SID from the network interface record, it is
not being used and therefore is "dead code".
Signed-off-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/security/selinux/netif.c b/security/selinux/netif.c
index e87ab94..ee49a73 100644
--- a/security/selinux/netif.c
+++ b/security/selinux/netif.c
@@ -7,6 +7,8 @@
* Author: James Morris <jmorris@redhat.com>
*
* Copyright (C) 2003 Red Hat, Inc., James Morris <jmorris@redhat.com>
+ * Copyright (C) 2007 Hewlett-Packard Development Company, L.P.
+ * Paul Moore <paul.moore@hp.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2,
@@ -29,14 +31,6 @@
#define SEL_NETIF_HASH_SIZE 64
#define SEL_NETIF_HASH_MAX 1024
-#undef DEBUG
-
-#ifdef DEBUG
-#define DEBUGP printk
-#else
-#define DEBUGP(format, args...)
-#endif
-
struct sel_netif
{
struct list_head list;
@@ -49,174 +43,217 @@
static DEFINE_SPINLOCK(sel_netif_lock);
static struct list_head sel_netif_hash[SEL_NETIF_HASH_SIZE];
-static inline u32 sel_netif_hasfn(struct net_device *dev)
+/**
+ * sel_netif_hashfn - Hashing function for the interface table
+ * @ifindex: the network interface
+ *
+ * Description:
+ * This is the hashing function for the network interface table, it returns the
+ * bucket number for the given interface.
+ *
+ */
+static inline u32 sel_netif_hashfn(int ifindex)
{
- return (dev->ifindex & (SEL_NETIF_HASH_SIZE - 1));
+ return (ifindex & (SEL_NETIF_HASH_SIZE - 1));
}
-/*
- * All of the devices should normally fit in the hash, so we optimize
- * for that case.
+/**
+ * sel_netif_find - Search for an interface record
+ * @ifindex: the network interface
+ *
+ * Description:
+ * Search the network interface table and return the record matching @ifindex.
+ * If an entry can not be found in the table return NULL.
+ *
*/
-static inline struct sel_netif *sel_netif_find(struct net_device *dev)
+static inline struct sel_netif *sel_netif_find(int ifindex)
{
- struct list_head *pos;
- int idx = sel_netif_hasfn(dev);
+ int idx = sel_netif_hashfn(ifindex);
+ struct sel_netif *netif;
- __list_for_each_rcu(pos, &sel_netif_hash[idx]) {
- struct sel_netif *netif = list_entry(pos,
- struct sel_netif, list);
- if (likely(netif->nsec.dev == dev))
+ list_for_each_entry_rcu(netif, &sel_netif_hash[idx], list)
+ /* all of the devices should normally fit in the hash, so we
+ * optimize for that case */
+ if (likely(netif->nsec.ifindex == ifindex))
return netif;
- }
+
return NULL;
}
+/**
+ * sel_netif_insert - Insert a new interface into the table
+ * @netif: the new interface record
+ *
+ * Description:
+ * Add a new interface record to the network interface hash table. Returns
+ * zero on success, negative values on failure.
+ *
+ */
static int sel_netif_insert(struct sel_netif *netif)
{
- int idx, ret = 0;
+ int idx;
- if (sel_netif_total >= SEL_NETIF_HASH_MAX) {
- ret = -ENOSPC;
- goto out;
- }
+ if (sel_netif_total >= SEL_NETIF_HASH_MAX)
+ return -ENOSPC;
- idx = sel_netif_hasfn(netif->nsec.dev);
+ idx = sel_netif_hashfn(netif->nsec.ifindex);
list_add_rcu(&netif->list, &sel_netif_hash[idx]);
sel_netif_total++;
-out:
- return ret;
+
+ return 0;
}
+/**
+ * sel_netif_free - Frees an interface entry
+ * @p: the entry's RCU field
+ *
+ * Description:
+ * This function is designed to be used as a callback to the call_rcu()
+ * function so that memory allocated to a hash table interface entry can be
+ * released safely.
+ *
+ */
static void sel_netif_free(struct rcu_head *p)
{
struct sel_netif *netif = container_of(p, struct sel_netif, rcu_head);
-
- DEBUGP("%s: %s\n", __FUNCTION__, netif->nsec.dev->name);
kfree(netif);
}
+/**
+ * sel_netif_destroy - Remove an interface record from the table
+ * @netif: the existing interface record
+ *
+ * Description:
+ * Remove an existing interface record from the network interface table.
+ *
+ */
static void sel_netif_destroy(struct sel_netif *netif)
{
- DEBUGP("%s: %s\n", __FUNCTION__, netif->nsec.dev->name);
-
list_del_rcu(&netif->list);
sel_netif_total--;
call_rcu(&netif->rcu_head, sel_netif_free);
}
-static struct sel_netif *sel_netif_lookup(struct net_device *dev)
+/**
+ * sel_netif_sid_slow - Lookup the SID of a network interface using the policy
+ * @ifindex: the network interface
+ * @sid: interface SID
+ *
+ * Description:
+ * This function determines the SID of a network interface by quering the
+ * security policy. The result is added to the network interface table to
+ * speedup future queries. Returns zero on success, negative values on
+ * failure.
+ *
+ */
+static int sel_netif_sid_slow(int ifindex, u32 *sid)
{
int ret;
- struct sel_netif *netif, *new;
- struct netif_security_struct *nsec;
+ struct sel_netif *netif;
+ struct sel_netif *new = NULL;
+ struct net_device *dev;
- netif = sel_netif_find(dev);
- if (likely(netif != NULL))
- goto out;
-
- new = kzalloc(sizeof(*new), GFP_ATOMIC);
- if (!new) {
- netif = ERR_PTR(-ENOMEM);
- goto out;
- }
-
- nsec = &new->nsec;
+ /* NOTE: we always use init's network namespace since we don't
+ * currently support containers */
- ret = security_netif_sid(dev->name, &nsec->if_sid, &nsec->msg_sid);
- if (ret < 0) {
- kfree(new);
- netif = ERR_PTR(ret);
- goto out;
- }
+ dev = dev_get_by_index(&init_net, ifindex);
+ if (dev == NULL)
+ return -ENOENT;
- nsec->dev = dev;
-
spin_lock_bh(&sel_netif_lock);
-
- netif = sel_netif_find(dev);
- if (netif) {
- spin_unlock_bh(&sel_netif_lock);
- kfree(new);
+ netif = sel_netif_find(ifindex);
+ if (netif != NULL) {
+ *sid = netif->nsec.sid;
+ ret = 0;
goto out;
}
-
+ new = kzalloc(sizeof(*new), GFP_ATOMIC);
+ if (new == NULL) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ ret = security_netif_sid(dev->name, &new->nsec.sid);
+ if (ret != 0)
+ goto out;
+ new->nsec.ifindex = ifindex;
ret = sel_netif_insert(new);
- spin_unlock_bh(&sel_netif_lock);
-
- if (ret) {
- kfree(new);
- netif = ERR_PTR(ret);
+ if (ret != 0)
goto out;
- }
+ *sid = new->nsec.sid;
- netif = new;
-
- DEBUGP("new: ifindex=%u name=%s if_sid=%u msg_sid=%u\n", dev->ifindex, dev->name,
- nsec->if_sid, nsec->msg_sid);
out:
- return netif;
-}
-
-static void sel_netif_assign_sids(u32 if_sid_in, u32 msg_sid_in, u32 *if_sid_out, u32 *msg_sid_out)
-{
- if (if_sid_out)
- *if_sid_out = if_sid_in;
- if (msg_sid_out)
- *msg_sid_out = msg_sid_in;
-}
-
-static int sel_netif_sids_slow(struct net_device *dev, u32 *if_sid, u32 *msg_sid)
-{
- int ret = 0;
- u32 tmp_if_sid, tmp_msg_sid;
-
- ret = security_netif_sid(dev->name, &tmp_if_sid, &tmp_msg_sid);
- if (!ret)
- sel_netif_assign_sids(tmp_if_sid, tmp_msg_sid, if_sid, msg_sid);
+ spin_unlock_bh(&sel_netif_lock);
+ dev_put(dev);
+ if (ret != 0)
+ kfree(new);
return ret;
}
-int sel_netif_sids(struct net_device *dev, u32 *if_sid, u32 *msg_sid)
+/**
+ * sel_netif_sid - Lookup the SID of a network interface
+ * @ifindex: the network interface
+ * @sid: interface SID
+ *
+ * Description:
+ * This function determines the SID of a network interface using the fastest
+ * method possible. First the interface 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_netif_sid(int ifindex, u32 *sid)
{
- int ret = 0;
struct sel_netif *netif;
rcu_read_lock();
- netif = sel_netif_lookup(dev);
- if (IS_ERR(netif)) {
+ netif = sel_netif_find(ifindex);
+ if (likely(netif != NULL)) {
+ *sid = netif->nsec.sid;
rcu_read_unlock();
- ret = sel_netif_sids_slow(dev, if_sid, msg_sid);
- goto out;
+ return 0;
}
- sel_netif_assign_sids(netif->nsec.if_sid, netif->nsec.msg_sid, if_sid, msg_sid);
rcu_read_unlock();
-out:
- return ret;
+
+ return sel_netif_sid_slow(ifindex, sid);
}
-static void sel_netif_kill(struct net_device *dev)
+/**
+ * sel_netif_kill - Remove an entry from the network interface table
+ * @ifindex: the network interface
+ *
+ * Description:
+ * This function removes the entry matching @ifindex from the network interface
+ * table if it exists.
+ *
+ */
+static void sel_netif_kill(int ifindex)
{
struct sel_netif *netif;
spin_lock_bh(&sel_netif_lock);
- netif = sel_netif_find(dev);
+ netif = sel_netif_find(ifindex);
if (netif)
sel_netif_destroy(netif);
spin_unlock_bh(&sel_netif_lock);
}
+/**
+ * sel_netif_flush - Flush the entire network interface table
+ *
+ * Description:
+ * Remove all entries from the network interface table.
+ *
+ */
static void sel_netif_flush(void)
{
int idx;
+ struct sel_netif *netif;
spin_lock_bh(&sel_netif_lock);
- for (idx = 0; idx < SEL_NETIF_HASH_SIZE; idx++) {
- struct sel_netif *netif;
-
+ for (idx = 0; idx < SEL_NETIF_HASH_SIZE; idx++)
list_for_each_entry(netif, &sel_netif_hash[idx], list)
sel_netif_destroy(netif);
- }
spin_unlock_bh(&sel_netif_lock);
}
@@ -239,7 +276,7 @@
return NOTIFY_DONE;
if (event == NETDEV_DOWN)
- sel_netif_kill(dev);
+ sel_netif_kill(dev->ifindex);
return NOTIFY_DONE;
}
@@ -250,10 +287,10 @@
static __init int sel_netif_init(void)
{
- int i, err = 0;
+ int i, err;
if (!selinux_enabled)
- goto out;
+ return 0;
for (i = 0; i < SEL_NETIF_HASH_SIZE; i++)
INIT_LIST_HEAD(&sel_netif_hash[i]);
@@ -265,7 +302,6 @@
if (err)
panic("avc_add_callback() failed, error %d\n", err);
-out:
return err;
}