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Date: Tue, 22 Dec 2015 11:46:53 +0000
From: Huw Davies <huw@...eweavers.com>
To: netdev@...r.kernel.org, linux-security-module@...r.kernel.org,
selinux@...ho.nsa.gov
Cc: Paul Moore <pmoore@...hat.com>
Subject: [RFC PATCH 17/17] calipso: Add a label cache.
This works in exactly the same way as the CIPSO label cache.
The idea is to allow the lsm to cache the result of a secattr
lookup so that it doesn't need to perform the lookup for
every skbuff.
It introduces two sysctl controls:
calipso_cache_enable - enables/disables the cache.
calipso_cache_bucket_size - sets the size of a cache bucket.
Signed-off-by: Huw Davies <huw@...eweavers.com>
---
include/net/calipso.h | 6 +
include/net/netlabel.h | 9 +-
net/ipv6/calipso.c | 264 +++++++++++++++++++++++++++++++++++++++-
net/ipv6/sysctl_net_ipv6.c | 19 +++
net/netlabel/netlabel_calipso.c | 38 ++++++
net/netlabel/netlabel_calipso.h | 3 +
net/netlabel/netlabel_kapi.c | 24 +++-
security/selinux/netlabel.c | 9 +-
8 files changed, 360 insertions(+), 12 deletions(-)
diff --git a/include/net/calipso.h b/include/net/calipso.h
index 99df89b..dac6302 100644
--- a/include/net/calipso.h
+++ b/include/net/calipso.h
@@ -62,6 +62,12 @@ struct calipso_doi {
struct rcu_head rcu;
};
+/*
+ * Sysctl Variables
+ */
+extern int calipso_cache_enabled;
+extern int calipso_cache_bucketsize;
+
#ifdef CONFIG_NETLABEL
int __init calipso_init(void);
void calipso_exit(void);
diff --git a/include/net/netlabel.h b/include/net/netlabel.h
index 1aed135..61e9c78 100644
--- a/include/net/netlabel.h
+++ b/include/net/netlabel.h
@@ -235,6 +235,8 @@ struct netlbl_lsm_secattr {
* @getattr: retrieve attr from memory block
* @skbuff_setattr: set the skbuff's attr
* @skbuff_delattr: remove the skbuff's attr
+ * @cache_invalidate: invalidate cache
+ * @cache_add: add cache entry
*
* Description:
* This structure is filled out by the CALIPSO engine and passed
@@ -269,6 +271,9 @@ struct netlbl_calipso_ops {
const struct calipso_doi *doi_def,
const struct netlbl_lsm_secattr *secattr);
int (*skbuff_delattr)(struct sk_buff *skb);
+ void (*cache_invalidate)(void);
+ int (*cache_add)(const unsigned char *calipso_ptr,
+ const struct netlbl_lsm_secattr *secattr);
};
/*
@@ -494,7 +499,7 @@ void netlbl_skbuff_err(struct sk_buff *skb, u16 family, int error, int gateway);
* LSM label mapping cache operations
*/
void netlbl_cache_invalidate(void);
-int netlbl_cache_add(const struct sk_buff *skb,
+int netlbl_cache_add(const struct sk_buff *skb, u16 family,
const struct netlbl_lsm_secattr *secattr);
/*
@@ -647,7 +652,7 @@ static inline void netlbl_cache_invalidate(void)
{
return;
}
-static inline int netlbl_cache_add(const struct sk_buff *skb,
+static inline int netlbl_cache_add(const struct sk_buff *skb, u16 family,
const struct netlbl_lsm_secattr *secattr)
{
return 0;
diff --git a/net/ipv6/calipso.c b/net/ipv6/calipso.c
index f3b7c43..61979ee 100644
--- a/net/ipv6/calipso.c
+++ b/net/ipv6/calipso.c
@@ -66,6 +66,255 @@
static DEFINE_SPINLOCK(calipso_doi_list_lock);
static LIST_HEAD(calipso_doi_list);
+/* Label mapping cache */
+int calipso_cache_enabled = 1;
+int calipso_cache_bucketsize = 10;
+#define CALIPSO_CACHE_BUCKETBITS 7
+#define CALIPSO_CACHE_BUCKETS BIT(CALIPSO_CACHE_BUCKETBITS)
+#define CALIPSO_CACHE_REORDERLIMIT 10
+struct calipso_map_cache_bkt {
+ spinlock_t lock;
+ u32 size;
+ struct list_head list;
+};
+
+struct calipso_map_cache_entry {
+ u32 hash;
+ unsigned char *key;
+ size_t key_len;
+
+ struct netlbl_lsm_cache *lsm_data;
+
+ u32 activity;
+ struct list_head list;
+};
+
+static struct calipso_map_cache_bkt *calipso_cache;
+
+/* Label Mapping Cache Functions
+ */
+
+/**
+ * calipso_cache_entry_free - Frees a cache entry
+ * @entry: the entry to free
+ *
+ * Description:
+ * This function frees the memory associated with a cache entry including the
+ * LSM cache data if there are no longer any users, i.e. reference count == 0.
+ *
+ */
+static void calipso_cache_entry_free(struct calipso_map_cache_entry *entry)
+{
+ if (entry->lsm_data)
+ netlbl_secattr_cache_free(entry->lsm_data);
+ kfree(entry->key);
+ kfree(entry);
+}
+
+/**
+ * calipso_map_cache_hash - Hashing function for the CALIPSO cache
+ * @key: the hash key
+ * @key_len: the length of the key in bytes
+ *
+ * Description:
+ * The CALIPSO tag hashing function. Returns a 32-bit hash value.
+ *
+ */
+static u32 calipso_map_cache_hash(const unsigned char *key, u32 key_len)
+{
+ return jhash(key, key_len, 0);
+}
+
+/**
+ * calipso_cache_init - Initialize the CALIPSO cache
+ *
+ * Description:
+ * Initializes the CALIPSO label mapping cache, this function should be called
+ * before any of the other functions defined in this file. Returns zero on
+ * success, negative values on error.
+ *
+ */
+static int __init calipso_cache_init(void)
+{
+ u32 iter;
+
+ calipso_cache = kcalloc(CALIPSO_CACHE_BUCKETS,
+ sizeof(struct calipso_map_cache_bkt),
+ GFP_KERNEL);
+ if (!calipso_cache)
+ return -ENOMEM;
+
+ for (iter = 0; iter < CALIPSO_CACHE_BUCKETS; iter++) {
+ spin_lock_init(&calipso_cache[iter].lock);
+ calipso_cache[iter].size = 0;
+ INIT_LIST_HEAD(&calipso_cache[iter].list);
+ }
+
+ return 0;
+}
+
+/**
+ * calipso_cache_invalidate - Invalidates the current CALIPSO cache
+ *
+ * Description:
+ * Invalidates and frees any entries in the CALIPSO cache. Returns zero on
+ * success and negative values on failure.
+ *
+ */
+static void calipso_cache_invalidate(void)
+{
+ struct calipso_map_cache_entry *entry, *tmp_entry;
+ u32 iter;
+
+ for (iter = 0; iter < CALIPSO_CACHE_BUCKETS; iter++) {
+ spin_lock_bh(&calipso_cache[iter].lock);
+ list_for_each_entry_safe(entry,
+ tmp_entry,
+ &calipso_cache[iter].list, list) {
+ list_del(&entry->list);
+ calipso_cache_entry_free(entry);
+ }
+ calipso_cache[iter].size = 0;
+ spin_unlock_bh(&calipso_cache[iter].lock);
+ }
+}
+
+/**
+ * calipso_cache_check - Check the CALIPSO cache for a label mapping
+ * @key: the buffer to check
+ * @key_len: buffer length in bytes
+ * @secattr: the security attribute struct to use
+ *
+ * Description:
+ * This function checks the cache to see if a label mapping already exists for
+ * the given key. If there is a match then the cache is adjusted and the
+ * @secattr struct is populated with the correct LSM security attributes. The
+ * cache is adjusted in the following manner if the entry is not already the
+ * first in the cache bucket:
+ *
+ * 1. The cache entry's activity counter is incremented
+ * 2. The previous (higher ranking) entry's activity counter is decremented
+ * 3. If the difference between the two activity counters is geater than
+ * CALIPSO_CACHE_REORDERLIMIT the two entries are swapped
+ *
+ * Returns zero on success, -ENOENT for a cache miss, and other negative values
+ * on error.
+ *
+ */
+static int calipso_cache_check(const unsigned char *key,
+ u32 key_len,
+ struct netlbl_lsm_secattr *secattr)
+{
+ u32 bkt;
+ struct calipso_map_cache_entry *entry;
+ struct calipso_map_cache_entry *prev_entry = NULL;
+ u32 hash;
+
+ if (!calipso_cache_enabled)
+ return -ENOENT;
+
+ hash = calipso_map_cache_hash(key, key_len);
+ bkt = hash & (CALIPSO_CACHE_BUCKETS - 1);
+ spin_lock_bh(&calipso_cache[bkt].lock);
+ list_for_each_entry(entry, &calipso_cache[bkt].list, list) {
+ if (entry->hash == hash &&
+ entry->key_len == key_len &&
+ memcmp(entry->key, key, key_len) == 0) {
+ entry->activity += 1;
+ atomic_inc(&entry->lsm_data->refcount);
+ secattr->cache = entry->lsm_data;
+ secattr->flags |= NETLBL_SECATTR_CACHE;
+ secattr->type = NETLBL_NLTYPE_CALIPSO;
+ if (!prev_entry) {
+ spin_unlock_bh(&calipso_cache[bkt].lock);
+ return 0;
+ }
+
+ if (prev_entry->activity > 0)
+ prev_entry->activity -= 1;
+ if (entry->activity > prev_entry->activity &&
+ entry->activity - prev_entry->activity >
+ CALIPSO_CACHE_REORDERLIMIT) {
+ __list_del(entry->list.prev, entry->list.next);
+ __list_add(&entry->list,
+ prev_entry->list.prev,
+ &prev_entry->list);
+ }
+
+ spin_unlock_bh(&calipso_cache[bkt].lock);
+ return 0;
+ }
+ prev_entry = entry;
+ }
+ spin_unlock_bh(&calipso_cache[bkt].lock);
+
+ return -ENOENT;
+}
+
+/**
+ * calipso_cache_add - Add an entry to the CALIPSO cache
+ * @calipso_ptr: the CALIPSO option
+ * @secattr: the packet's security attributes
+ *
+ * Description:
+ * Add a new entry into the CALIPSO label mapping cache. Add the new entry to
+ * head of the cache bucket's list, if the cache bucket is out of room remove
+ * the last entry in the list first. It is important to note that there is
+ * currently no checking for duplicate keys. Returns zero on success,
+ * negative values on failure. The key stored starts at calipso_ptr + 2,
+ * i.e. the type and length bytes are not stored, this corresponds to
+ * calipso_ptr[1] bytes of data.
+ *
+ */
+static int calipso_cache_add(const unsigned char *calipso_ptr,
+ const struct netlbl_lsm_secattr *secattr)
+{
+ int ret_val = -EPERM;
+ u32 bkt;
+ struct calipso_map_cache_entry *entry = NULL;
+ struct calipso_map_cache_entry *old_entry = NULL;
+ u32 calipso_ptr_len;
+
+ if (!calipso_cache_enabled || calipso_cache_bucketsize <= 0)
+ return 0;
+
+ calipso_ptr_len = calipso_ptr[1];
+
+ entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
+ if (!entry)
+ return -ENOMEM;
+ entry->key = kmemdup(calipso_ptr + 2, calipso_ptr_len, GFP_ATOMIC);
+ if (!entry->key) {
+ ret_val = -ENOMEM;
+ goto cache_add_failure;
+ }
+ entry->key_len = calipso_ptr_len;
+ entry->hash = calipso_map_cache_hash(calipso_ptr, calipso_ptr_len);
+ atomic_inc(&secattr->cache->refcount);
+ entry->lsm_data = secattr->cache;
+
+ bkt = entry->hash & (CALIPSO_CACHE_BUCKETS - 1);
+ spin_lock_bh(&calipso_cache[bkt].lock);
+ if (calipso_cache[bkt].size < calipso_cache_bucketsize) {
+ list_add(&entry->list, &calipso_cache[bkt].list);
+ calipso_cache[bkt].size += 1;
+ } else {
+ old_entry = list_entry(calipso_cache[bkt].list.prev,
+ struct calipso_map_cache_entry, list);
+ list_del(&old_entry->list);
+ list_add(&entry->list, &calipso_cache[bkt].list);
+ calipso_cache_entry_free(old_entry);
+ }
+ spin_unlock_bh(&calipso_cache[bkt].lock);
+
+ return 0;
+
+cache_add_failure:
+ if (entry)
+ calipso_cache_entry_free(entry);
+ return ret_val;
+}
+
/* DOI List Functions
*/
@@ -789,6 +1038,9 @@ static int calipso_getattr(const unsigned char *calipso,
if (cat_len + 8 > len)
return -EINVAL;
+ if (calipso_cache_check(calipso + 2, calipso[1], secattr) == 0)
+ return 0;
+
doi = get_unaligned_be32(calipso + 2);
rcu_read_lock();
doi_def = calipso_doi_search(doi);
@@ -1197,6 +1449,8 @@ static const struct netlbl_calipso_ops ops = {
.getattr = calipso_getattr,
.skbuff_setattr = calipso_skbuff_setattr,
.skbuff_delattr = calipso_skbuff_delattr,
+ .cache_invalidate = calipso_cache_invalidate,
+ .cache_add = calipso_cache_add
};
/**
@@ -1209,11 +1463,17 @@ static const struct netlbl_calipso_ops ops = {
*/
int __init calipso_init(void)
{
- netlbl_calipso_ops_register(&ops);
- return 0;
+ int ret_val;
+
+ ret_val = calipso_cache_init();
+ if (!ret_val)
+ netlbl_calipso_ops_register(&ops);
+ return ret_val;
}
void calipso_exit(void)
{
netlbl_calipso_ops_register(NULL);
+ calipso_cache_invalidate();
+ kfree(calipso_cache);
}
diff --git a/net/ipv6/sysctl_net_ipv6.c b/net/ipv6/sysctl_net_ipv6.c
index 45243bb..69c50e7 100644
--- a/net/ipv6/sysctl_net_ipv6.c
+++ b/net/ipv6/sysctl_net_ipv6.c
@@ -15,6 +15,9 @@
#include <net/ipv6.h>
#include <net/addrconf.h>
#include <net/inet_frag.h>
+#ifdef CONFIG_NETLABEL
+#include <net/calipso.h>
+#endif
static int one = 1;
static int auto_flowlabels_min;
@@ -106,6 +109,22 @@ static struct ctl_table ipv6_rotable[] = {
.proc_handler = proc_dointvec_minmax,
.extra1 = &one
},
+#ifdef CONFIG_NETLABEL
+ {
+ .procname = "calipso_cache_enable",
+ .data = &calipso_cache_enabled,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec,
+ },
+ {
+ .procname = "calipso_cache_bucket_size",
+ .data = &calipso_cache_bucketsize,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec,
+ },
+#endif /* CONFIG_NETLABEL */
{ }
};
diff --git a/net/netlabel/netlabel_calipso.c b/net/netlabel/netlabel_calipso.c
index ad16b47..89a3e52 100644
--- a/net/netlabel/netlabel_calipso.c
+++ b/net/netlabel/netlabel_calipso.c
@@ -703,3 +703,41 @@ int calipso_skbuff_delattr(struct sk_buff *skb)
ret_val = ops->skbuff_delattr(skb);
return ret_val;
}
+
+/**
+ * calipso_cache_invalidate - Invalidates the current CALIPSO cache
+ *
+ * Description:
+ * Invalidates and frees any entries in the CALIPSO cache. Returns zero on
+ * success and negative values on failure.
+ *
+ */
+void calipso_cache_invalidate(void)
+{
+ const struct netlbl_calipso_ops *ops = netlbl_calipso_ops_get();
+
+ if (ops)
+ ops->cache_invalidate();
+}
+
+/**
+ * calipso_cache_add - Add an entry to the CALIPSO cache
+ * @calipso_ptr: the CALIPSO option
+ * @secattr: the packet's security attributes
+ *
+ * Description:
+ * Add a new entry into the CALIPSO label mapping cache.
+ * Returns zero on success, negative values on failure.
+ *
+ */
+int calipso_cache_add(const unsigned char *calipso_ptr,
+ const struct netlbl_lsm_secattr *secattr)
+
+{
+ int ret_val = -ENOMSG;
+ const struct netlbl_calipso_ops *ops = netlbl_calipso_ops_get();
+
+ if (ops)
+ ret_val = ops->cache_add(calipso_ptr, secattr);
+ return ret_val;
+}
diff --git a/net/netlabel/netlabel_calipso.h b/net/netlabel/netlabel_calipso.h
index 34a5f82..c3ef8bb 100644
--- a/net/netlabel/netlabel_calipso.h
+++ b/net/netlabel/netlabel_calipso.h
@@ -146,5 +146,8 @@ int calipso_skbuff_setattr(struct sk_buff *skb,
const struct calipso_doi *doi_def,
const struct netlbl_lsm_secattr *secattr);
int calipso_skbuff_delattr(struct sk_buff *skb);
+void calipso_cache_invalidate(void);
+int calipso_cache_add(const unsigned char *calipso_ptr,
+ const struct netlbl_lsm_secattr *secattr);
#endif
diff --git a/net/netlabel/netlabel_kapi.c b/net/netlabel/netlabel_kapi.c
index 35df8f5..d534731 100644
--- a/net/netlabel/netlabel_kapi.c
+++ b/net/netlabel/netlabel_kapi.c
@@ -1282,11 +1282,15 @@ void netlbl_skbuff_err(struct sk_buff *skb, u16 family, int error, int gateway)
void netlbl_cache_invalidate(void)
{
cipso_v4_cache_invalidate();
+#if IS_ENABLED(CONFIG_IPV6)
+ calipso_cache_invalidate();
+#endif /* IPv6 */
}
/**
* netlbl_cache_add - Add an entry to a NetLabel protocol cache
* @skb: the packet
+ * @family: the family
* @secattr: the packet's security attributes
*
* Description:
@@ -1295,7 +1299,7 @@ void netlbl_cache_invalidate(void)
* values on error.
*
*/
-int netlbl_cache_add(const struct sk_buff *skb,
+int netlbl_cache_add(const struct sk_buff *skb, u16 family,
const struct netlbl_lsm_secattr *secattr)
{
unsigned char *ptr;
@@ -1303,10 +1307,20 @@ int netlbl_cache_add(const struct sk_buff *skb,
if ((secattr->flags & NETLBL_SECATTR_CACHE) == 0)
return -ENOMSG;
- ptr = cipso_v4_optptr(skb);
- if (ptr)
- return cipso_v4_cache_add(ptr, secattr);
-
+ switch (family) {
+ case AF_INET:
+ ptr = cipso_v4_optptr(skb);
+ if (ptr)
+ return cipso_v4_cache_add(ptr, secattr);
+ break;
+#if IS_ENABLED(CONFIG_IPV6)
+ case AF_INET6:
+ ptr = calipso_optptr(skb);
+ if (ptr)
+ return calipso_cache_add(ptr, secattr);
+ break;
+#endif /* IPv6 */
+ }
return -ENOMSG;
}
diff --git a/security/selinux/netlabel.c b/security/selinux/netlabel.c
index dfca50d..aaba667 100644
--- a/security/selinux/netlabel.c
+++ b/security/selinux/netlabel.c
@@ -54,6 +54,7 @@
*
*/
static int selinux_netlbl_sidlookup_cached(struct sk_buff *skb,
+ u16 family,
struct netlbl_lsm_secattr *secattr,
u32 *sid)
{
@@ -63,7 +64,7 @@ static int selinux_netlbl_sidlookup_cached(struct sk_buff *skb,
if (rc == 0 &&
(secattr->flags & NETLBL_SECATTR_CACHEABLE) &&
(secattr->flags & NETLBL_SECATTR_CACHE))
- netlbl_cache_add(skb, secattr);
+ netlbl_cache_add(skb, family, secattr);
return rc;
}
@@ -214,7 +215,8 @@ int selinux_netlbl_skbuff_getsid(struct sk_buff *skb,
netlbl_secattr_init(&secattr);
rc = netlbl_skbuff_getattr(skb, family, &secattr);
if (rc == 0 && secattr.flags != NETLBL_SECATTR_NONE)
- rc = selinux_netlbl_sidlookup_cached(skb, &secattr, sid);
+ rc = selinux_netlbl_sidlookup_cached(skb, family,
+ &secattr, sid);
else
*sid = SECSID_NULL;
*type = secattr.type;
@@ -382,7 +384,8 @@ int selinux_netlbl_sock_rcv_skb(struct sk_security_struct *sksec,
netlbl_secattr_init(&secattr);
rc = netlbl_skbuff_getattr(skb, family, &secattr);
if (rc == 0 && secattr.flags != NETLBL_SECATTR_NONE)
- rc = selinux_netlbl_sidlookup_cached(skb, &secattr, &nlbl_sid);
+ rc = selinux_netlbl_sidlookup_cached(skb, family,
+ &secattr, &nlbl_sid);
else
nlbl_sid = SECINITSID_UNLABELED;
netlbl_secattr_destroy(&secattr);
--
1.8.0
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