[PATCH 3/9] nftables: nft_rbtree: fix locking
From: Patrick McHardy <hidden>
Date: 2015-01-30 07:46:46
Also in:
netfilter-devel
Subsystem:
netfilter, networking [general], the rest · Maintainers:
Pablo Neira Ayuso, Florian Westphal, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
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 contexts Signed-off-by: Patrick McHardy <redacted> --- net/netfilter/nft_rbtree.c | 12 +++--------- 1 file changed, 3 insertions(+), 9 deletions(-)
diff --git a/net/netfilter/nft_rbtree.c b/net/netfilter/nft_rbtree.c
index 46214f2..417796f 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; }
@@ -190,7 +188,6 @@ static void nft_rbtree_walk(const struct nft_ctx *ctx, struct nft_set_elem elem; struct rb_node *node; - spin_lock_bh(&nft_rbtree_lock); for (node = rb_first(&priv->root); node != NULL; node = rb_next(node)) { if (iter->count < iter->skip) goto cont;
@@ -203,14 +200,11 @@ static void nft_rbtree_walk(const struct nft_ctx *ctx, elem.flags = rbe->flags; iter->err = iter->fn(ctx, set, iter, &elem); - if (iter->err < 0) { - spin_unlock_bh(&nft_rbtree_lock); + if (iter->err < 0) return; - } cont: iter->count++; } - spin_unlock_bh(&nft_rbtree_lock); } static unsigned int nft_rbtree_privsize(const struct nlattr * const nla[])
--
2.1.0