diff options
| author | Liping Zhang <liping.zhang@spreadtrum.com> | 2016-07-12 19:45:00 +0800 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2016-07-12 16:24:22 +0200 |
| commit | 3101e0fc1f6e809d38fbb5845c6c5eb0eefeda07 (patch) | |
| tree | 79b1f0820d001fa4c34efec874fc527377808a6d /net | |
| parent | c2b9b4fee8ab86f2bb657e5ac48d803879e92765 (diff) | |
| download | linux-3101e0fc1f6e809d38fbb5845c6c5eb0eefeda07.tar.gz linux-3101e0fc1f6e809d38fbb5845c6c5eb0eefeda07.tar.bz2 linux-3101e0fc1f6e809d38fbb5845c6c5eb0eefeda07.zip | |
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.c | 3 |
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; |