[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <CA+55aFymwBJ9CxOpnjnNxOxncHLkwfeFQ4Mm=ZhWBZDEAfAd1Q@mail.gmail.com>
Date: Mon, 19 Sep 2011 11:32:24 -0700
From: Linus Torvalds <torvalds@...ux-foundation.org>
To: Andi Kleen <andi@...stfloor.org>
Cc: Balbir Singh <bsingharora@...il.com>, Vasiliy Kulikov <segoon@...nwall.com>,
Shailabh Nagar <nagar@...ibm.com>, linux-kernel@...r.kernel.org, security@...nel.org,
Eric Paris <eparis@...hat.com>, Stephen Wilson <wilsons@...rt.ca>,
KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>, David Rientjes <rientjes@...gle.com>,
Andrew Morton <akpm@...ux-foundation.org>, Balbir Singh <balbir@...ux.vnet.ibm.com>,
kernel-hardening@...ts.openwall.com
Subject: Re: [Security] [PATCH 2/2] taskstats: restrict access to user
On Mon, Sep 19, 2011 at 11:29 AM, Andi Kleen <andi@...stfloor.org> wrote:
>>
>> #define KB 1024
>
> Needs to be 1024ULL, because the counters are 64bit.
>
>> #define MB (1024*KB)
>> +#define KB_MASK (~(KB-1))
>
> Otherwise you lose the upper 32bits here.
No, it's an "int" constant, so it will sign-extend properly when it
gets extended to 64 bits.
It's "unsigned int" etc that can be dangerous in these kinds of situations.
(Of course, in other contexts, sign-extensions of masks is *bad*. So
it depends on what you do)
Linus
Powered by blists - more mailing lists
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
