From: David Laight <David.Laight@ACULAB.COM>
To: "'H. Peter Anvin'" <hpa@zytor.com>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Jann Horn <jannh@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Andy Lutomirski <luto@kernel.org>,
"kernel-hardening@lists.openwall.com"
<kernel-hardening@lists.openwall.com>,
"Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"x86@kernel.org" <x86@kernel.org>
Subject: RE: [PATCH] x86/fpu: XRSTOR is expected to raise #GP
Date: Wed, 28 Nov 2018 15:27:28 +0000 [thread overview]
Message-ID: <52276fe27116406eb601a99704459f80@AcuMS.aculab.com> (raw)
In-Reply-To: <4d4c4f1f-72e3-0182-151e-8bd455ccd143@zytor.com>
From: H. Peter Anvin
> Sent: 26 November 2018 19:50
> On 11/26/18 9:49 AM, Sebastian Andrzej Siewior wrote:
> > On 2018-11-26 18:27:06 [+0100], Jann Horn wrote:
> >> commit 75045f77f7a7 ("x86/extable: Introduce _ASM_EXTABLE_UA for uaccess
> >> fixups") incorrectly replaced the fixup entry for XSTATE_OP with a
> >> user-#PF-only fixup. However, XRSTOR can also raise #GP when the supplied
> >> address points to userspace memory. Change it back.
> >
> > The #GP is raised if the xstate content is invalid. But I guess the
> > details don't matter.
> >
> >> Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> >> Fixes: 75045f77f7a7 ("x86/extable: Introduce _ASM_EXTABLE_UA for uaccess fixups")
> >> Signed-off-by: Jann Horn <jannh@google.com>
> > Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> >
>
> It does matter -- please correct the patch description, or we might have some
> serious confusion at some arbitrary point in the future with the result that
> the bug gets re-introduced; it would not be the first time.
Better still note it in the code.
David
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Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2018-11-28 15:27 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-26 17:27 Jann Horn
2018-11-26 17:49 ` Sebastian Andrzej Siewior
2018-11-26 19:49 ` H. Peter Anvin
2018-11-28 15:27 ` David Laight [this message]
2018-11-28 15:34 ` Sebastian Andrzej Siewior
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