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| author | Vasily Khoruzhick <vasilykh@arista.com> | 2018-10-25 12:15:43 -0700 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2018-11-03 14:16:28 +0100 |
| commit | f393808dc64149ccd0e5a8427505ba2974a59854 (patch) | |
| tree | 023e5b21bd9552c5f15764d0f8ed50e7a5c574ce /net | |
| parent | e4844c9c62a0fe47980d6c3d4b7a096a5d755925 (diff) | |
| download | linux-f393808dc64149ccd0e5a8427505ba2974a59854.tar.gz linux-f393808dc64149ccd0e5a8427505ba2974a59854.tar.bz2 linux-f393808dc64149ccd0e5a8427505ba2974a59854.zip | |
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.c | 13 |
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) { |