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author | Changli Gao <xiaosuo@gmail.com> | 2011-01-05 04:23:23 (GMT) |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2011-01-06 19:22:20 (GMT) |
commit | f682cefa5ad204d3bfaa54a58046c66d2d035ac1 (patch) | |
tree | 8c55a0b722df666bb0a75f5749c7457cd5d44f3b /net/netfilter | |
parent | 6623e3b24a5ebb07e81648c478d286a1329ab891 (diff) | |
download | linux-f682cefa5ad204d3bfaa54a58046c66d2d035ac1.tar.xz |
netfilter: fix the race when initializing nf_ct_expect_hash_rnd
Since nf_ct_expect_dst_hash() may be called without nf_conntrack_lock
locked, nf_ct_expect_hash_rnd should be initialized in the atomic way.
In this patch, we use nf_conntrack_hash_rnd instead of
nf_ct_expect_hash_rnd.
Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/netfilter')
-rw-r--r-- | net/netfilter/nf_conntrack_core.c | 30 | ||||
-rw-r--r-- | net/netfilter/nf_conntrack_expect.c | 10 |
2 files changed, 20 insertions, 20 deletions
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c index 27a5ea6..e615119 100644 --- a/net/netfilter/nf_conntrack_core.c +++ b/net/netfilter/nf_conntrack_core.c @@ -65,7 +65,7 @@ EXPORT_SYMBOL_GPL(nf_conntrack_max); DEFINE_PER_CPU(struct nf_conn, nf_conntrack_untracked); EXPORT_PER_CPU_SYMBOL(nf_conntrack_untracked); -static unsigned int nf_conntrack_hash_rnd __read_mostly; +unsigned int nf_conntrack_hash_rnd __read_mostly; static u32 hash_conntrack_raw(const struct nf_conntrack_tuple *tuple, u16 zone) { @@ -596,6 +596,21 @@ static noinline int early_drop(struct net *net, unsigned int hash) return dropped; } +void init_nf_conntrack_hash_rnd(void) +{ + unsigned int rand; + + /* + * Why not initialize nf_conntrack_rnd in a "init()" function ? + * Because there isn't enough entropy when system initializing, + * and we initialize it as late as possible. + */ + do { + get_random_bytes(&rand, sizeof(rand)); + } while (!rand); + cmpxchg(&nf_conntrack_hash_rnd, 0, rand); +} + static struct nf_conn * __nf_conntrack_alloc(struct net *net, u16 zone, const struct nf_conntrack_tuple *orig, @@ -605,18 +620,7 @@ __nf_conntrack_alloc(struct net *net, u16 zone, struct nf_conn *ct; if (unlikely(!nf_conntrack_hash_rnd)) { - unsigned int rand; - - /* - * Why not initialize nf_conntrack_rnd in a "init()" function ? - * Because there isn't enough entropy when system initializing, - * and we initialize it as late as possible. - */ - do { - get_random_bytes(&rand, sizeof(rand)); - } while (!rand); - cmpxchg(&nf_conntrack_hash_rnd, 0, rand); - + init_nf_conntrack_hash_rnd(); /* recompute the hash as nf_conntrack_hash_rnd is initialized */ hash = hash_conntrack_raw(orig, zone); } diff --git a/net/netfilter/nf_conntrack_expect.c b/net/netfilter/nf_conntrack_expect.c index 46e8966..a20fb0b 100644 --- a/net/netfilter/nf_conntrack_expect.c +++ b/net/netfilter/nf_conntrack_expect.c @@ -32,9 +32,7 @@ unsigned int nf_ct_expect_hsize __read_mostly; EXPORT_SYMBOL_GPL(nf_ct_expect_hsize); -static unsigned int nf_ct_expect_hash_rnd __read_mostly; unsigned int nf_ct_expect_max __read_mostly; -static int nf_ct_expect_hash_rnd_initted __read_mostly; static struct kmem_cache *nf_ct_expect_cachep __read_mostly; @@ -77,15 +75,13 @@ static unsigned int nf_ct_expect_dst_hash(const struct nf_conntrack_tuple *tuple { unsigned int hash; - if (unlikely(!nf_ct_expect_hash_rnd_initted)) { - get_random_bytes(&nf_ct_expect_hash_rnd, - sizeof(nf_ct_expect_hash_rnd)); - nf_ct_expect_hash_rnd_initted = 1; + if (unlikely(!nf_conntrack_hash_rnd)) { + init_nf_conntrack_hash_rnd(); } hash = jhash2(tuple->dst.u3.all, ARRAY_SIZE(tuple->dst.u3.all), (((tuple->dst.protonum ^ tuple->src.l3num) << 16) | - (__force __u16)tuple->dst.u.all) ^ nf_ct_expect_hash_rnd); + (__force __u16)tuple->dst.u.all) ^ nf_conntrack_hash_rnd); return ((u64)hash * nf_ct_expect_hsize) >> 32; } |