lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:   Mon, 11 May 2020 10:24:44 +0300
From:   Paul Blakey <>
To:     Pablo Neira Ayuso <>
Cc:     Oz Shlomo <>, Roi Dayan <>,, Saeed Mahameed <>,
Subject: Re: [PATCH net] netfilter: flowtable: Fix expired flow not being
 deleted from software

On 5/11/2020 1:26 AM, Pablo Neira Ayuso wrote:
> On Wed, May 06, 2020 at 02:27:29PM +0300, Paul Blakey wrote:
>> Once a flow is considered expired, it is marked as DYING, and
>> scheduled a delete from hardware. The flow will be deleted from
>> software, in the next gc_step after hardware deletes the flow
>> (and flow is marked DEAD). Till that happens, the flow's timeout
>> might be updated from a previous scheduled stats, or software packets
>> (refresh). This will cause the gc_step to no longer consider the flow
>> expired, and it will not be deleted from software.
>> Fix that by looking at the DYING flag as in deciding
>> a flow should be deleted from software.
> Would this work for you?
> The idea is to skip the refresh if this has already expired.
> Thanks.

The idea is ok, but timeout check + update isn't atomic (need atomic_inc_unlesss
or something like that), and there is also
the hardware stats which if comes too late (after gc finds it expired) might
bring a flow back to life.

Powered by blists - more mailing lists