From a639e7ca8e8282b75be2724a28bfc788aa3bb156 Mon Sep 17 00:00:00 2001 From: Paul Moore Date: Fri, 25 Apr 2008 15:03:34 -0400 Subject: SELinux: Made netnode cache adds faster When adding new entries to the network node cache we would walk the entire hash bucket to make sure we didn't cross a threshold (done to bound the cache size). This isn't a very quick or elegant solution for something which is supposed to be quick-ish so add a counter to each hash bucket to track the size of the bucket and eliminate the need to walk the entire bucket list on each add. Signed-off-by: Paul Moore Signed-off-by: James Morris --- security/selinux/netnode.c | 104 +++++++++++++++++++++------------------------ 1 file changed, 49 insertions(+), 55 deletions(-) (limited to 'security/selinux') diff --git a/security/selinux/netnode.c b/security/selinux/netnode.c index 2edc4c5e0c61..b6ccd09379f1 100644 --- a/security/selinux/netnode.c +++ b/security/selinux/netnode.c @@ -40,11 +40,17 @@ #include #include +#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; @@ -60,7 +66,7 @@ struct sel_netnode { static LIST_HEAD(sel_netnode_list); static DEFINE_SPINLOCK(sel_netnode_lock); -static struct list_head sel_netnode_hash[SEL_NETNODE_HASH_SIZE]; +static struct sel_netnode_bkt sel_netnode_hash[SEL_NETNODE_HASH_SIZE]; /** * sel_netnode_free - Frees a node entry @@ -87,7 +93,7 @@ static void sel_netnode_free(struct rcu_head *p) * the bucket number for the given IP address. * */ -static u32 sel_netnode_hashfn_ipv4(__be32 addr) +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 */ @@ -103,7 +109,7 @@ static u32 sel_netnode_hashfn_ipv4(__be32 addr) * the bucket number for the given IP address. * */ -static u32 sel_netnode_hashfn_ipv6(const struct in6_addr *addr) +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 @@ -123,7 +129,7 @@ static u32 sel_netnode_hashfn_ipv6(const struct in6_addr *addr) */ static struct sel_netnode *sel_netnode_find(const void *addr, u16 family) { - u32 idx; + unsigned int idx; struct sel_netnode *node; switch (family) { @@ -137,7 +143,7 @@ static struct sel_netnode *sel_netnode_find(const void *addr, u16 family) BUG(); } - list_for_each_entry_rcu(node, &sel_netnode_hash[idx], list) + list_for_each_entry_rcu(node, &sel_netnode_hash[idx].list, list) if (node->nsec.family == family) switch (family) { case PF_INET: @@ -159,15 +165,12 @@ static struct sel_netnode *sel_netnode_find(const void *addr, u16 family) * @node: the new node record * * Description: - * Add a new node record to the network address hash table. Returns zero on - * success, negative values on failure. + * Add a new node record to the network address hash table. * */ -static int sel_netnode_insert(struct sel_netnode *node) +static void sel_netnode_insert(struct sel_netnode *node) { - u32 idx; - u32 count = 0; - struct sel_netnode *iter; + unsigned int idx; switch (node->nsec.family) { case PF_INET: @@ -179,32 +182,21 @@ static int sel_netnode_insert(struct sel_netnode *node) default: BUG(); } - list_add_rcu(&node->list, &sel_netnode_hash[idx]); + + INIT_RCU_HEAD(&node->rcu); /* 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_for_each_entry(iter, &sel_netnode_hash[idx], list) - if (++count > SEL_NETNODE_HASH_BKT_LIMIT) { - list_del_rcu(&iter->list); - call_rcu(&iter->rcu, sel_netnode_free); - break; - } - - return 0; -} - -/** - * sel_netnode_destroy - Remove a node record from the table - * @node: the existing node record - * - * Description: - * Remove an existing node record from the network address table. - * - */ -static void sel_netnode_destroy(struct sel_netnode *node) -{ - list_del_rcu(&node->list); - call_rcu(&node->rcu, sel_netnode_free); + 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(sel_netnode_hash[idx].list.prev), + struct sel_netnode, list); + list_del_rcu(&tail->list); + call_rcu(&tail->rcu, sel_netnode_free); + } else + sel_netnode_hash[idx].size++; } /** @@ -222,7 +214,7 @@ static void sel_netnode_destroy(struct sel_netnode *node) */ static int sel_netnode_sid_slow(void *addr, u16 family, u32 *sid) { - int ret; + int ret = -ENOMEM; struct sel_netnode *node; struct sel_netnode *new = NULL; @@ -230,25 +222,21 @@ static int sel_netnode_sid_slow(void *addr, u16 family, u32 *sid) node = sel_netnode_find(addr, family); if (node != NULL) { *sid = node->nsec.sid; - ret = 0; - goto out; + spin_unlock_bh(&sel_netnode_lock); + return 0; } new = kzalloc(sizeof(*new), GFP_ATOMIC); - if (new == NULL) { - ret = -ENOMEM; + if (new == NULL) goto out; - } switch (family) { case PF_INET: ret = security_node_sid(PF_INET, - addr, sizeof(struct in_addr), - &new->nsec.sid); + 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), - &new->nsec.sid); + addr, sizeof(struct in6_addr), sid); ipv6_addr_copy(&new->nsec.addr.ipv6, addr); break; default: @@ -256,11 +244,10 @@ static int sel_netnode_sid_slow(void *addr, u16 family, u32 *sid) } if (ret != 0) goto out; + new->nsec.family = family; - ret = sel_netnode_insert(new); - if (ret != 0) - goto out; - *sid = new->nsec.sid; + new->nsec.sid = *sid; + sel_netnode_insert(new); out: spin_unlock_bh(&sel_netnode_lock); @@ -312,13 +299,18 @@ int sel_netnode_sid(void *addr, u16 family, u32 *sid) */ static void sel_netnode_flush(void) { - u32 idx; - struct sel_netnode *node; + 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(node, &sel_netnode_hash[idx], list) - sel_netnode_destroy(node); + 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); + call_rcu(&node->rcu, sel_netnode_free); + } + sel_netnode_hash[idx].size = 0; + } spin_unlock_bh(&sel_netnode_lock); } @@ -340,8 +332,10 @@ static __init int sel_netnode_init(void) if (!selinux_enabled) return 0; - for (iter = 0; iter < SEL_NETNODE_HASH_SIZE; iter++) - INIT_LIST_HEAD(&sel_netnode_hash[iter]); + for (iter = 0; iter < SEL_NETNODE_HASH_SIZE; iter++) { + INIT_LIST_HEAD(&sel_netnode_hash[iter].list); + sel_netnode_hash[iter].size = 0; + } ret = avc_add_callback(sel_netnode_avc_callback, AVC_CALLBACK_RESET, SECSID_NULL, SECSID_NULL, SECCLASS_NULL, 0); -- cgit v1.2.3-58-ga151