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 <paul.moore@xxxxxx>
---
security/selinux/netnode.c | 67 +++++++++++++++++++++-----------------------
1 files changed, 32 insertions(+), 35 deletions(-)
diff --git a/security/selinux/netnode.c b/security/selinux/netnode.c
index f3c526f..6d71763 100644
--- a/security/selinux/netnode.c
+++ b/security/selinux/netnode.c
@@ -40,11 +40,17 @@
#include <net/ipv6.h>
#include <asm/bug.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;
@@ -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:
@@ -165,9 +171,7 @@ static struct sel_netnode *sel_netnode_find(const void *addr, u16 family)
*/
static int 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:
@@ -179,35 +183,22 @@ static int sel_netnode_insert(struct sel_netnode *node)
default:
BUG();
}
- list_add_rcu(&node->list, &sel_netnode_hash[idx]);
/* 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;
- }
+ 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(node->list.prev, struct sel_netnode, list);
+ list_del_rcu(node->list.prev);
+ call_rcu(&tail->rcu, sel_netnode_free);
+ } else
+ sel_netnode_hash[idx].size++;
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);
-}
-
-/**
* sel_netnode_sid_slow - Lookup the SID of a network address using the policy
* @addr: the IP address
* @family: the address family
@@ -312,13 +303,17 @@ int sel_netnode_sid(void *addr, u16 family, u32 *sid)
*/
static void sel_netnode_flush(void)
{
- u32 idx;
+ unsigned int idx;
struct sel_netnode *node;
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(node, &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 +335,10 @@ 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);
--
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