netfilter: nft_rbtree: fix locking

Fix a race condition and unnecessary locking:

* the root rb_node must only be accessed under the lock in nft_rbtree_lookup()
* the lock is not needed in lookup functions in netlink context

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Patrick McHardy 2015-03-21 15:19:14 +00:00 committed by Pablo Neira Ayuso
parent 8d0451638a
commit 16c45eda96

View File

@ -37,10 +37,11 @@ static bool nft_rbtree_lookup(const struct nft_set *set,
{
const struct nft_rbtree *priv = nft_set_priv(set);
const struct nft_rbtree_elem *rbe, *interval = NULL;
const struct rb_node *parent = priv->root.rb_node;
const struct rb_node *parent;
int d;
spin_lock_bh(&nft_rbtree_lock);
parent = priv->root.rb_node;
while (parent != NULL) {
rbe = rb_entry(parent, struct nft_rbtree_elem, node);
@ -158,7 +159,6 @@ static int nft_rbtree_get(const struct nft_set *set, struct nft_set_elem *elem)
struct nft_rbtree_elem *rbe;
int d;
spin_lock_bh(&nft_rbtree_lock);
while (parent != NULL) {
rbe = rb_entry(parent, struct nft_rbtree_elem, node);
@ -173,11 +173,9 @@ static int nft_rbtree_get(const struct nft_set *set, struct nft_set_elem *elem)
!(rbe->flags & NFT_SET_ELEM_INTERVAL_END))
nft_data_copy(&elem->data, rbe->data);
elem->flags = rbe->flags;
spin_unlock_bh(&nft_rbtree_lock);
return 0;
}
}
spin_unlock_bh(&nft_rbtree_lock);
return -ENOENT;
}