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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 /security | |
| parent | c25d5180441e344a3368d100c57f0a481c6944f7 (diff) | |
| download | linux-3.10-ffb733c65000ee701294f7b80c4eca2a5f335637.tar.gz linux-3.10-ffb733c65000ee701294f7b80c4eca2a5f335637.tar.bz2 linux-3.10-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 'security')
| -rw-r--r-- | security/selinux/ss/services.c | 37 |
1 files changed, 21 insertions, 16 deletions
diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c index 0c219a1b324..bb2d2bc869b 100644 --- a/security/selinux/ss/services.c +++ b/security/selinux/ss/services.c @@ -2172,7 +2172,12 @@ struct netlbl_cache { */ static void selinux_netlbl_cache_free(const void *data) { - struct netlbl_cache *cache = NETLBL_CACHE(data); + struct netlbl_cache *cache; + + if (data == NULL) + return; + + cache = NETLBL_CACHE(data); switch (cache->type) { case NETLBL_CACHE_T_MLS: ebitmap_destroy(&cache->data.mls_label.level[0].cat); @@ -2197,17 +2202,20 @@ static void selinux_netlbl_cache_add(struct sk_buff *skb, struct context *ctx) struct netlbl_lsm_secattr secattr; netlbl_secattr_init(&secattr); + secattr.cache = netlbl_secattr_cache_alloc(GFP_ATOMIC); + if (secattr.cache == NULL) + goto netlbl_cache_add_return; cache = kzalloc(sizeof(*cache), GFP_ATOMIC); if (cache == NULL) - goto netlbl_cache_add_failure; - secattr.cache.free = selinux_netlbl_cache_free; - secattr.cache.data = (void *)cache; + goto netlbl_cache_add_return; + secattr.cache->free = selinux_netlbl_cache_free; + secattr.cache->data = (void *)cache; cache->type = NETLBL_CACHE_T_MLS; if (ebitmap_cpy(&cache->data.mls_label.level[0].cat, &ctx->range.level[0].cat) != 0) - goto netlbl_cache_add_failure; + goto netlbl_cache_add_return; cache->data.mls_label.level[1].cat.highbit = cache->data.mls_label.level[0].cat.highbit; cache->data.mls_label.level[1].cat.node = @@ -2215,13 +2223,10 @@ static void selinux_netlbl_cache_add(struct sk_buff *skb, struct context *ctx) cache->data.mls_label.level[0].sens = ctx->range.level[0].sens; cache->data.mls_label.level[1].sens = ctx->range.level[0].sens; - if (netlbl_cache_add(skb, &secattr) != 0) - goto netlbl_cache_add_failure; - - return; + netlbl_cache_add(skb, &secattr); -netlbl_cache_add_failure: - netlbl_secattr_destroy(&secattr, 1); +netlbl_cache_add_return: + netlbl_secattr_destroy(&secattr); } /** @@ -2263,8 +2268,8 @@ static int selinux_netlbl_secattr_to_sid(struct sk_buff *skb, POLICY_RDLOCK; - if (secattr->cache.data) { - cache = NETLBL_CACHE(secattr->cache.data); + if (secattr->cache) { + cache = NETLBL_CACHE(secattr->cache->data); switch (cache->type) { case NETLBL_CACHE_T_SID: *sid = cache->data.sid; @@ -2369,7 +2374,7 @@ static int selinux_netlbl_skbuff_getsid(struct sk_buff *skb, &secattr, base_sid, sid); - netlbl_secattr_destroy(&secattr, 0); + netlbl_secattr_destroy(&secattr); return rc; } @@ -2415,7 +2420,7 @@ static int selinux_netlbl_socket_setsid(struct socket *sock, u32 sid) if (rc == 0) sksec->nlbl_state = NLBL_LABELED; - netlbl_secattr_destroy(&secattr, 0); + netlbl_secattr_destroy(&secattr); netlbl_socket_setsid_return: POLICY_RDUNLOCK; @@ -2517,7 +2522,7 @@ void selinux_netlbl_sock_graft(struct sock *sk, struct socket *sock) sksec->sid, &nlbl_peer_sid) == 0) sksec->peer_sid = nlbl_peer_sid; - netlbl_secattr_destroy(&secattr, 0); + netlbl_secattr_destroy(&secattr); sksec->nlbl_state = NLBL_REQUIRE; |