linux-kernel - Re: [PATCH] Ceph: Fix a use-after-free bug in ceph_destroy

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Message-ID: <alpine.LNX.2.00.1012252234340.10759@swampdragon.chaosbits.net>
Date:	Sat, 25 Dec 2010 22:35:20 +0100 (CET)
From:	Jesper Juhl <jj@...osbits.net>
To:	richard -rw- weinberger <richard.weinberger@...il.com>
cc:	ceph-devel@...r.kernel.org, linux-kernel@...r.kernel.org,
	netdev@...r.kernel.org, Sage Weil <sage@...dream.net>,
	"David S. Miller" <davem@...emloft.net>
Subject: Re: [PATCH] Ceph: Fix a use-after-free bug in
 ceph_destroy_client().

On Sat, 25 Dec 2010, richard -rw- weinberger wrote:

> On Sat, Dec 25, 2010 at 10:24 PM, Jesper Juhl <jj@...osbits.net> wrote:
> > On Sat, 25 Dec 2010, richard -rw- weinberger wrote:
> >
> >> On Sat, Dec 25, 2010 at 7:17 PM, Jesper Juhl <jj@...osbits.net> wrote:
> >> > Hello,
> >> >
> >> > In net/ceph/ceph_common.c::ceph_destroy_client() the pointer 'client' is
> >> > freed by kfree() and subsequently used in a call to dout() - use after
> >> > free bug.
> >>
> >> Not really. %p reads only the address of "client".
> >> kfree() does not alter this address.
> >>
> >
> > Ok, I see your point and you are correct. But still, the patch does not
> > change behaviour and it makes it absolutely clear that there's no
> > use-after-free bug, so it might still have merit... or?
> 
> Your patch does not fix a bug.
> I would say it's a style fix.
> 
At this point in time I'd agree. :-)

-- 
Jesper Juhl <jj@...osbits.net>            http://www.chaosbits.net/
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Plain text mails only, please.

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