From: Kuniyuki Iwashima <kuniyu@amazon.com>
To: <edumazet@google.com>
Cc: <davem@davemloft.net>, <dsahern@kernel.org>,
<eric.dumazet@gmail.com>, <kuba@kernel.org>, <kuniyu@amazon.com>,
<netdev@vger.kernel.org>, <pabeni@redhat.com>
Subject: Re: [PATCH net-next] ipv6: switch inet6_addr_hash() to less predictable hash
Date: Tue, 8 Oct 2024 09:21:05 -0700 [thread overview]
Message-ID: <20241008162105.94440-1-kuniyu@amazon.com> (raw)
In-Reply-To: <20241008120101.734521-1-edumazet@google.com>
From: Eric Dumazet <edumazet@google.com>
Date: Tue, 8 Oct 2024 12:01:01 +0000
> In commit 3f27fb23219e ("ipv6: addrconf: add per netns perturbation
> in inet6_addr_hash()"), I added net_hash_mix() in inet6_addr_hash()
> to get better hash dispersion, at a time all netns were sharing the
> hash table.
>
> Since then, commit 21a216a8fc63 ("ipv6/addrconf: allocate a per
> netns hash table") made the hash table per netns.
>
> We could remove the net_hash_mix() from inet6_addr_hash(), but
> there is still an issue with ipv6_addr_hash().
>
> It is highly predictable and a malicious user can easily create
> thousands of IPv6 addresses all stored in the same hash bucket.
>
> Switch to __ipv6_addr_jhash(). We could use a dedicated
> secret, or reuse net_hash_mix() as I did in this patch.
>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
next prev parent reply other threads:[~2024-10-08 16:21 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-08 12:01 [PATCH net-next] ipv6: switch inet6_addr_hash() to less predictable hash Eric Dumazet
2024-10-08 14:40 ` David Ahern
2024-10-08 16:21 ` Kuniyuki Iwashima [this message]
2024-10-10 2:50 ` patchwork-bot+netdevbpf
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