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authorLiping Zhang <liping.zhang@spreadtrum.com>2016-07-12 19:45:00 +0800
committerPablo Neira Ayuso <pablo@netfilter.org>2016-07-12 16:24:22 +0200
commit3101e0fc1f6e809d38fbb5845c6c5eb0eefeda07 (patch)
tree79b1f0820d001fa4c34efec874fc527377808a6d /net
parentc2b9b4fee8ab86f2bb657e5ac48d803879e92765 (diff)
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netfilter: conntrack: protect early_drop by rcu read lock
User can add ct entry via nfnetlink(IPCTNL_MSG_CT_NEW), and if the total number reach the nf_conntrack_max, we will try to drop some ct entries. But in this case(the main function call path is ctnetlink_create_conntrack -> nf_conntrack_alloc -> early_drop), rcu_read_lock is not held, so race with hash resize will happen. Fixes: 242922a02717 ("netfilter: conntrack: simplify early_drop") Cc: Florian Westphal <fw@strlen.de> Signed-off-by: Liping Zhang <liping.zhang@spreadtrum.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net')
-rw-r--r--net/netfilter/nf_conntrack_core.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index e0e9c9a0f5ba..2d46225501c1 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -880,6 +880,7 @@ static noinline int early_drop(struct net *net, unsigned int _hash)
struct hlist_nulls_head *ct_hash;
unsigned hash, sequence, drops;
+ rcu_read_lock();
do {
sequence = read_seqcount_begin(&nf_conntrack_generation);
hash = scale_hash(_hash++);
@@ -887,6 +888,8 @@ static noinline int early_drop(struct net *net, unsigned int _hash)
} while (read_seqcount_retry(&nf_conntrack_generation, sequence));
drops = early_drop_list(net, &ct_hash[hash]);
+ rcu_read_unlock();
+
if (drops) {
NF_CT_STAT_ADD_ATOMIC(net, early_drop, drops);
return true;