From e8bfdb9d0dfc1231a6a71e849dfbd4447acdfff6 Mon Sep 17 00:00:00 2001 From: Paul Moore Date: Tue, 29 Jan 2008 08:38:08 -0500 Subject: 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 Signed-off-by: James Morris --- security/selinux/netif.c | 254 +++++++++++++++++++++++++++-------------------- 1 file changed, 145 insertions(+), 109 deletions(-) (limited to 'security/selinux/netif.c') diff --git a/security/selinux/netif.c b/security/selinux/netif.c index e87ab948104c..ee49a7382875 100644 --- a/security/selinux/netif.c +++ b/security/selinux/netif.c @@ -7,6 +7,8 @@ * Author: James Morris * * Copyright (C) 2003 Red Hat, Inc., James Morris + * Copyright (C) 2007 Hewlett-Packard Development Company, L.P. + * Paul Moore * * 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 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) +/** + * 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; } - - ret = sel_netif_insert(new); - spin_unlock_bh(&sel_netif_lock); - - if (ret) { - kfree(new); - netif = ERR_PTR(ret); + 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); + 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 @@ static int sel_netif_netdev_notifier_handler(struct notifier_block *this, return NOTIFY_DONE; if (event == NETDEV_DOWN) - sel_netif_kill(dev); + sel_netif_kill(dev->ifindex); return NOTIFY_DONE; } @@ -250,10 +287,10 @@ static struct notifier_block sel_netif_netdev_notifier = { 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 @@ static __init int sel_netif_init(void) if (err) panic("avc_add_callback() failed, error %d\n", err); -out: return err; } -- cgit v1.2.3-59-g8ed1b