| From | Luis Henriques <> | Subject | [PATCH 3.16.y-ckt 125/129] netfilter: nft_rbtree: fix locking | Date | Fri, 22 May 2015 09:58:30 +0100 |
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3.16.7-ckt12 -stable review patch. If anyone has any objections, please let me know.
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From: Patrick McHardy <kaber@trash.net>
commit 16c45eda96038aae848b6cfd42e2bf4b5e80f365 upstream.
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> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- net/netfilter/nft_rbtree.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/net/netfilter/nft_rbtree.c b/net/netfilter/nft_rbtree.c index e1836ff88199..0636387c7c80 100644 --- a/net/netfilter/nft_rbtree.c +++ b/net/netfilter/nft_rbtree.c @@ -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; }
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