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| author | paul.moore@hp.com <paul.moore@hp.com> | 2006-10-04 11:46:31 -0400 |
|---|---|---|
| committer | David S. Miller <davem@sunset.davemloft.net> | 2006-10-11 23:59:29 -0700 |
| commit | ffb733c65000ee701294f7b80c4eca2a5f335637 (patch) | |
| tree | edda8e25792fe4a7bf0c619787949291276b9ed7 /net/ipv4/cipso_ipv4.c | |
| parent | c25d5180441e344a3368d100c57f0a481c6944f7 (diff) | |
| download | linux-ffb733c65000ee701294f7b80c4eca2a5f335637.tar.gz linux-ffb733c65000ee701294f7b80c4eca2a5f335637.tar.bz2 linux-ffb733c65000ee701294f7b80c4eca2a5f335637.zip | |
NetLabel: fix a cache race condition
Testing revealed a problem with the NetLabel cache where a cached entry could
be freed while in use by the LSM layer causing an oops and other problems.
This patch fixes that problem by introducing a reference counter to the cache
entry so that it is only freed when it is no longer in use.
Signed-off-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'net/ipv4/cipso_ipv4.c')
| -rw-r--r-- | net/ipv4/cipso_ipv4.c | 18 |
1 files changed, 10 insertions, 8 deletions
diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c index a8e2e879a647..bde8ccaa1531 100644 --- a/net/ipv4/cipso_ipv4.c +++ b/net/ipv4/cipso_ipv4.c @@ -43,6 +43,7 @@ #include <net/tcp.h> #include <net/netlabel.h> #include <net/cipso_ipv4.h> +#include <asm/atomic.h> #include <asm/bug.h> struct cipso_v4_domhsh_entry { @@ -79,7 +80,7 @@ struct cipso_v4_map_cache_entry { unsigned char *key; size_t key_len; - struct netlbl_lsm_cache lsm_data; + struct netlbl_lsm_cache *lsm_data; u32 activity; struct list_head list; @@ -188,13 +189,14 @@ static void cipso_v4_doi_domhsh_free(struct rcu_head *entry) * @entry: the entry to free * * Description: - * This function frees the memory associated with a cache entry. + * 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 cipso_v4_cache_entry_free(struct cipso_v4_map_cache_entry *entry) { - if (entry->lsm_data.free) - entry->lsm_data.free(entry->lsm_data.data); + if (entry->lsm_data) + netlbl_secattr_cache_free(entry->lsm_data); kfree(entry->key); kfree(entry); } @@ -315,8 +317,8 @@ static int cipso_v4_cache_check(const unsigned char *key, entry->key_len == key_len && memcmp(entry->key, key, key_len) == 0) { entry->activity += 1; - secattr->cache.free = entry->lsm_data.free; - secattr->cache.data = entry->lsm_data.data; + atomic_inc(&entry->lsm_data->refcount); + secattr->cache = entry->lsm_data; if (prev_entry == NULL) { spin_unlock_bh(&cipso_v4_cache[bkt].lock); return 0; @@ -383,8 +385,8 @@ int cipso_v4_cache_add(const struct sk_buff *skb, memcpy(entry->key, cipso_ptr, cipso_ptr_len); entry->key_len = cipso_ptr_len; entry->hash = cipso_v4_map_cache_hash(cipso_ptr, cipso_ptr_len); - entry->lsm_data.free = secattr->cache.free; - entry->lsm_data.data = secattr->cache.data; + atomic_inc(&secattr->cache->refcount); + entry->lsm_data = secattr->cache; bkt = entry->hash & (CIPSO_V4_CACHE_BUCKETBITS - 1); spin_lock_bh(&cipso_v4_cache[bkt].lock); |