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From: Greg KH <gregkh@linuxfoundation.org>
To: Amit Klein <aksecurity@gmail.com>
Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org,
	edumazet@google.com, w@1wt.eu, davem@davemloft.net,
	netdev@vger.kernel.org
Subject: Re: [PATCH 4.19] inet: use bigger hash table for IP ID generation (backported to 4.19)
Date: Mon, 21 Jun 2021 17:28:38 +0200	[thread overview]
Message-ID: <YNCwJqtKKCskB2Au@kroah.com> (raw)
In-Reply-To: <60cb0586.1c69fb81.8015b.37a1@mx.google.com>

On Thu, Jun 17, 2021 at 01:19:18AM -0700, Amit Klein wrote:
> Subject: inet: use bigger hash table for IP ID generation (backported to 4.19)
> From: Amit Klein <aksecurity@gmail.com>
> 
> This is a backport to 4.19 of the following patch, originally
> developed by Eric Dumazet.
> 
> In commit 73f156a6e8c1 ("inetpeer: get rid of ip_id_count")
> I used a very small hash table that could be abused
> by patient attackers to reveal sensitive information.
> 
> Switch to a dynamic sizing, depending on RAM size.
> 
> Typical big hosts will now use 128x more storage (2 MB)
> to get a similar increase in security and reduction
> of hash collisions.
> 
> As a bonus, use of alloc_large_system_hash() spreads
> allocated memory among all NUMA nodes.
> 
> Fixes: 73f156a6e8c1 ("inetpeer: get rid of ip_id_count")
> Reported-by: Amit Klein <aksecurity@gmail.com>
> Cc: stable@vger.kernel.org
> Cc: Eric Dumazet <edumazet@google.com>
> Cc: Willy Tarreau <w@1wt.eu>
> ---
>  net/ipv4/route.c | 42 ++++++++++++++++++++++++++++--------------
>  1 file changed, 28 insertions(+), 14 deletions(-)
> 
> (limited to 'net/ipv4/route.c')

I had to dig up what the upstream git commit id was for this, please
specify it next time :(

I've queued this, and the 4.14 version up.  Can you create a 4.4.y and
4.9.y version as well?

thanks,

greg k-h

  reply	other threads:[~2021-06-21 15:28 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-17  8:19 Amit Klein
2021-06-21 15:28 ` Greg KH [this message]
2021-06-21 16:01   ` Amit Klein
2021-06-22  9:10   ` Amit Klein

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