Message-ID: <1414614013.5330.90.camel@dhcp-9-2-203-236.watson.ibm.com>
Subject: Re: [GIT PULL] Fix for Integrity subsystem null pointer deref
From: Mimi Zohar <zohar@linux.vnet.ibm.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Dan Carpenter <dan.carpenter@oracle.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        LSM List <linux-security-module@vger.kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        "security@kernel.org" <security@kernel.org>,
        James Morris <jmorris@namei.org>
Date: Wed, 29 Oct 2014 16:20:13 -0400
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On Wed, 2014-10-29 at 11:51 -0700, Andy Lutomirski wrote: 
> On Wed, Oct 29, 2014 at 11:36 AM, Dan Carpenter
> <dan.carpenter@oracle.com> wrote:
> > On Wed, Oct 29, 2014 at 09:23:45AM -0700, Andy Lutomirski wrote:
> >> I have no idea what the semantics are.  All I'm saying is that it
> >> looks like the code still accesses memory past the end of the buffer.
> >> The buffer isn't a null pointer, so the symptom is different, but it
> >> may still be a security bug.
> >>
> >> --Andy
> >
> > It only reads one byte into the struct "xattr_data->type" so checking
> > for non-zero is sufficient and the patch is fine.
> 
> Indeed.  Still... eww.  I don't like code that, upon local inspection,
> is apparently wrong, even though it's coincidentally correct due to
> some other far away condition.

No, the code may be incomplete, but definitely not wrong.

Mimi

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