From: Mikael Pettersson <mikpe@it.uu.se>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>,
Mikael Pettersson <mikpe@it.uu.se>, Ingo Molnar <mingo@elte.hu>,
Thomas Gleixner <tglx@linutronix.de>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] x86: ia32_signal: remove unnecessary padding
Date: Thu, 13 Nov 2008 09:45:12 +0100 [thread overview]
Message-ID: <18715.59672.641830.690773@harpo.it.uu.se> (raw)
In-Reply-To: <491B1C7C.5000906@zytor.com>
H. Peter Anvin writes:
> Hiroshi Shimamoto wrote:
> > H. Peter Anvin wrote:
> >> Mikael Pettersson wrote:
> >>> It does cause each signal delivery to leak 2 uninitialised
> >>> kernel bytes to the end of retcode[], which seems unnecessary.
> >> Not just unnecessary, it is a huge no-no for security.
> >
> > Am I missing important thing?
> > The frame->retcode is 8 bytes and packed structure with padding
> > is 10 bytes each, and the code is copied to user stack 8 bytes only.
> >
> > err |= __copy_to_user(frame->retcode, &code, 8);
> >
> > I don't think the behavior is changed.
> >
>
> Ah, nevermind, then. Then it fine, obviously.
Agreed. I wonder how on earth those templates ended
up as 10 bytes large when retcode[] always has been
8 bytes.
next prev parent reply other threads:[~2008-11-13 8:47 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-12 3:09 [PATCH 1/2] x86: signal_32: introduce retcode and rt_retcode Hiroshi Shimamoto
2008-11-12 3:11 ` [PATCH 2/2] x86: ia32_signal: remove unnecessary padding Hiroshi Shimamoto
2008-11-12 11:29 ` Ingo Molnar
2008-11-12 12:33 ` Mikael Pettersson
2008-11-12 17:12 ` H. Peter Anvin
2008-11-12 18:02 ` Hiroshi Shimamoto
2008-11-12 18:12 ` H. Peter Anvin
2008-11-13 8:45 ` Mikael Pettersson [this message]
2008-11-13 17:38 ` H. Peter Anvin
2008-11-12 12:56 ` Andi Kleen
2008-11-12 18:34 ` Hiroshi Shimamoto
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