netdev - Re: Fwd: Simple kernel attack using socketpair. easy, 100% reproductiblle, works under guest. no way to protect :(

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Message-ID: <AANLkTi=NTFXXY42nh+j3xM4n-NTPaz=fWKmAY=MpsHze@mail.gmail.com>
Date:	Thu, 25 Nov 2010 13:35:30 +0500
From:	Марк Коренберг 
	<socketpair@...il.com>
To:	Eric Dumazet <eric.dumazet@...il.com>
Cc:	netdev@...r.kernel.org
Subject: Re: Fwd: Simple kernel attack using socketpair. easy, 100%
 reproductiblle, works under guest. no way to protect :(

quick and dirty fix will be not to allow to pass unix socket inside
unix socket. I think it would not break much applications.

2010/11/25 Eric Dumazet <eric.dumazet@...il.com>:
> Le jeudi 25 novembre 2010 à 12:52 +0500, Марк Коренберг a écrit :
>> ---------- Forwarded message ----------
>> From: Марк Коренберг <socketpair@...il.com>
>> Date: 2010/11/25
>> Subject: Re: Simple kernel attack using socketpair. easy, 100%
>> reproductiblle, works under guest. no way to protect :(
>> To: Eric Dumazet <eric.dumazet@...il.com>
>>
>>
>> 2010/11/25 Eric Dumazet <eric.dumazet@...il.com>:
>> > Le jeudi 25 novembre 2010 à 11:52 +0500, Марк Коренберг a écrit :
>> >> Well, It seems, that patch likely will fix 100% CPU usage.
>> >>
>> >> But what about eating all available descriptors in kernel ? vulnerability ?
>> >>
>> >
>> > It doesnt fix cpu usage actually, your program eats 100% of one cpu,
>> > like the following one :
>> >
>> > for (;;) ;
>> >
>> > If you want not eat 100% cpu, I suggest you add some blocking calls,
>> > like usleep(10000)
>> >
>> > for (;;) usleep(10000);
>> >
>> > Patch only makes sure kernel wont eat too much memory to store inflight
>> > unix sockets.
>>
>> I have attached source which proove, that loop not inside this
>> program, but inside kernel.
>>
>> --
>
> Better send a fix, now that thousand of people know how to kill a linux
> machine.
>
> Congrats.
>
>
>
>



-- 
Segmentation fault
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