SELinux: Fix a RCU free problem with the netport cache
The netport cache doesn't free resources in a manner which is safe or orderly.
This patch fixes this by adding in a missing call to rcu_dereference() in
sel_netport_insert() as well as some general cleanup throughout the file.
Signed-off-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/security/selinux/netport.c b/security/selinux/netport.c
index 68ede3c..90b4cff 100644
--- a/security/selinux/netport.c
+++ b/security/selinux/netport.c
@@ -114,8 +114,7 @@
idx = sel_netport_hashfn(pnum);
list_for_each_entry_rcu(port, &sel_netport_hash[idx].list, list)
- if (port->psec.port == pnum &&
- port->psec.protocol == protocol)
+ if (port->psec.port == pnum && port->psec.protocol == protocol)
return port;
return NULL;
@@ -126,11 +125,10 @@
* @port: the new port record
*
* Description:
- * Add a new port record to the network address hash table. Returns zero on
- * success, negative values on failure.
+ * Add a new port record to the network address hash table.
*
*/
-static int sel_netport_insert(struct sel_netport *port)
+static void sel_netport_insert(struct sel_netport *port)
{
unsigned int idx;
@@ -140,13 +138,13 @@
list_add_rcu(&port->list, &sel_netport_hash[idx].list);
if (sel_netport_hash[idx].size == SEL_NETPORT_HASH_BKT_LIMIT) {
struct sel_netport *tail;
- tail = list_entry(port->list.prev, struct sel_netport, list);
- list_del_rcu(port->list.prev);
+ tail = list_entry(
+ rcu_dereference(sel_netport_hash[idx].list.prev),
+ struct sel_netport, list);
+ list_del_rcu(&tail->list);
call_rcu(&tail->rcu, sel_netport_free);
} else
sel_netport_hash[idx].size++;
-
- return 0;
}
/**
@@ -163,7 +161,7 @@
*/
static int sel_netport_sid_slow(u8 protocol, u16 pnum, u32 *sid)
{
- int ret;
+ int ret = -ENOMEM;
struct sel_netport *port;
struct sel_netport *new = NULL;
@@ -171,23 +169,20 @@
port = sel_netport_find(protocol, pnum);
if (port != NULL) {
*sid = port->psec.sid;
- ret = 0;
- goto out;
+ spin_unlock_bh(&sel_netport_lock);
+ return 0;
}
new = kzalloc(sizeof(*new), GFP_ATOMIC);
- if (new == NULL) {
- ret = -ENOMEM;
+ if (new == NULL)
goto out;
- }
- ret = security_port_sid(protocol, pnum, &new->psec.sid);
+ ret = security_port_sid(protocol, pnum, sid);
if (ret != 0)
goto out;
+
new->psec.port = pnum;
new->psec.protocol = protocol;
- ret = sel_netport_insert(new);
- if (ret != 0)
- goto out;
- *sid = new->psec.sid;
+ new->psec.sid = *sid;
+ sel_netport_insert(new);
out:
spin_unlock_bh(&sel_netport_lock);
@@ -239,11 +234,12 @@
static void sel_netport_flush(void)
{
unsigned int idx;
- struct sel_netport *port;
+ struct sel_netport *port, *port_tmp;
spin_lock_bh(&sel_netport_lock);
for (idx = 0; idx < SEL_NETPORT_HASH_SIZE; idx++) {
- list_for_each_entry(port, &sel_netport_hash[idx].list, list) {
+ list_for_each_entry_safe(port, port_tmp,
+ &sel_netport_hash[idx].list, list) {
list_del_rcu(&port->list);
call_rcu(&port->rcu, sel_netport_free);
}