/* * Network interface table. * * Network interfaces (devices) do not have a security field, so we * maintain a table associating each interface with a SID. * * Author: James Morris <jmorris@redhat.com> * * Copyright (C) 2003 Red Hat, Inc., James Morris <jmorris@redhat.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, * as published by the Free Software Foundation. */ #include <linux/init.h> #include <linux/types.h> #include <linux/stddef.h> #include <linux/kernel.h> #include <linux/list.h> #include <linux/notifier.h> #include <linux/netdevice.h> #include <linux/rcupdate.h> #include "security.h" #include "objsec.h" #include "netif.h" #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; struct netif_security_struct nsec; struct rcu_head rcu_head; }; static u32 sel_netif_total; static LIST_HEAD(sel_netif_list); 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) { return (dev->ifindex & (SEL_NETIF_HASH_SIZE - 1)); } /* * All of the devices should normally fit in the hash, so we optimize * for that case. */ static inline struct sel_netif *sel_netif_find(struct net_device *dev) { struct list_head *pos; int idx = sel_netif_hasfn(dev); __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)) return netif; } return NULL; } static int sel_netif_insert(struct sel_netif *netif) { int idx, ret = 0; if (sel_netif_total >= SEL_NETIF_HASH_MAX) { ret = -ENOSPC; goto out; } idx = sel_netif_hasfn(netif->nsec.dev); list_add_rcu(&netif->list, &sel_netif_hash[idx]); sel_netif_total++; out: return ret; } 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); } 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) { int ret; struct sel_netif *netif, *new; struct netif_security_struct *nsec; 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; ret = security_netif_sid(dev->name, &nsec->if_sid, &nsec->msg_sid); if (ret < 0) { kfree(new); netif = ERR_PTR(ret); goto out; } nsec->dev = dev; spin_lock_bh(&sel_netif_lock); netif = sel_netif_find(dev); if (netif) { spin_unlock_bh(&sel_netif_lock); kfree(new); goto out; } ret = sel_netif_insert(new); spin_unlock_bh(&sel_netif_lock); if (ret) { kfree(new); netif = ERR_PTR(ret); goto out; } 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); return ret; } int sel_netif_sids(struct net_device *dev, u32 *if_sid, u32 *msg_sid) { int ret = 0; struct sel_netif *netif; rcu_read_lock(); netif = sel_netif_lookup(dev); if (IS_ERR(netif)) { rcu_read_unlock(); ret = sel_netif_sids_slow(dev, if_sid, msg_sid); goto out; } sel_netif_assign_sids(netif->nsec.if_sid, netif->nsec.msg_sid, if_sid, msg_sid); rcu_read_unlock(); out: return ret; } static void sel_netif_kill(struct net_device *dev) { struct sel_netif *netif; spin_lock_bh(&sel_netif_lock); netif = sel_netif_find(dev); if (netif) sel_netif_destroy(netif); spin_unlock_bh(&sel_netif_lock); } static void sel_netif_flush(void) { int idx; spin_lock_bh(&sel_netif_lock); for (idx = 0; idx < SEL_NETIF_HASH_SIZE; idx++) { struct sel_netif *netif; list_for_each_entry(netif, &sel_netif_hash[idx], list) sel_netif_destroy(netif); } spin_unlock_bh(&sel_netif_lock); } static int sel_netif_avc_callback(u32 event, u32 ssid, u32 tsid, u16 class, u32 perms, u32 *retained) { if (event == AVC_CALLBACK_RESET) { sel_netif_flush(); synchronize_net(); } return 0; } static int sel_netif_netdev_notifier_handler(struct notifier_block *this, unsigned long event, void *ptr) { struct net_device *dev = ptr; if (event == NETDEV_DOWN) sel_netif_kill(dev); return NOTIFY_DONE; } static struct notifier_block sel_netif_netdev_notifier = { .notifier_call = sel_netif_netdev_notifier_handler, }; static __init int sel_netif_init(void) { int i, err = 0; if (!selinux_enabled) goto out; for (i = 0; i < SEL_NETIF_HASH_SIZE; i++) INIT_LIST_HEAD(&sel_netif_hash[i]); register_netdevice_notifier(&sel_netif_netdev_notifier); err = avc_add_callback(sel_netif_avc_callback, AVC_CALLBACK_RESET, SECSID_NULL, SECSID_NULL, SECCLASS_NULL, 0); if (err) panic("avc_add_callback() failed, error %d\n", err); out: return err; } __initcall(sel_netif_init);