From ffb733c65000ee701294f7b80c4eca2a5f335637 Mon Sep 17 00:00:00 2001
From: "paul.moore@hp.com" <paul.moore@hp.com>
Date: Wed, 4 Oct 2006 11:46:31 -0400
Subject: 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>
---
security/selinux/ss/services.c | 37 +++++++++++++++++++++----------------
1 file changed, 21 insertions(+), 16 deletions(-)
(limited to 'security/selinux')
diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index 0c219a1..bb2d2bc 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;
--
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