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authorVasily Khoruzhick <vasilykh@arista.com>2018-10-25 12:15:43 -0700
committerPablo Neira Ayuso <pablo@netfilter.org>2018-11-03 14:16:28 +0100
commitf393808dc64149ccd0e5a8427505ba2974a59854 (patch)
tree023e5b21bd9552c5f15764d0f8ed50e7a5c574ce /net
parente4844c9c62a0fe47980d6c3d4b7a096a5d755925 (diff)
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netfilter: conntrack: fix calculation of next bucket number in early_drop
If there's no entry to drop in bucket that corresponds to the hash, early_drop() should look for it in other buckets. But since it increments hash instead of bucket number, it actually looks in the same bucket 8 times: hsize is 16k by default (14 bits) and hash is 32-bit value, so reciprocal_scale(hash, hsize) returns the same value for hash..hash+7 in most cases. Fix it by increasing bucket number instead of hash and rename _hash to bucket to avoid future confusion. Fixes: 3e86638e9a0b ("netfilter: conntrack: consider ct netns in early_drop logic") Cc: <stable@vger.kernel.org> # v4.7+ Signed-off-by: Vasily Khoruzhick <vasilykh@arista.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net')
-rw-r--r--net/netfilter/nf_conntrack_core.c13
1 files changed, 8 insertions, 5 deletions
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index ca1168d67fac..e92e749aff53 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -1073,19 +1073,22 @@ static unsigned int early_drop_list(struct net *net,
return drops;
}
-static noinline int early_drop(struct net *net, unsigned int _hash)
+static noinline int early_drop(struct net *net, unsigned int hash)
{
- unsigned int i;
+ unsigned int i, bucket;
for (i = 0; i < NF_CT_EVICTION_RANGE; i++) {
struct hlist_nulls_head *ct_hash;
- unsigned int hash, hsize, drops;
+ unsigned int hsize, drops;
rcu_read_lock();
nf_conntrack_get_ht(&ct_hash, &hsize);
- hash = reciprocal_scale(_hash++, hsize);
+ if (!i)
+ bucket = reciprocal_scale(hash, hsize);
+ else
+ bucket = (bucket + 1) % hsize;
- drops = early_drop_list(net, &ct_hash[hash]);
+ drops = early_drop_list(net, &ct_hash[bucket]);
rcu_read_unlock();
if (drops) {