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From: Thomas Gleixner <tglx@linutronix.de>
To: Alexander Potapenko <glider@google.com>,
	"Chang S. Bae" <chang.seok.bae@intel.com>,
	Borislav Petkov <bp@suse.de>
Cc: Dmitriy Vyukov <dvyukov@google.com>,
	Marco Elver <elver@google.com>,
	Taras Madan <tarasmadan@google.com>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: Potential information leak in save_xstate_epilog()
Date: Sat, 27 Nov 2021 21:26:04 +0100	[thread overview]
Message-ID: <87fsrhfiqr.ffs@tglx> (raw)
In-Reply-To: <CAG_fn=V9T6OKPonSjsi9PmWB0hMHFC=yawozdft8i1-MSxrv=w@mail.gmail.com>

On Fri, Nov 26 2021 at 12:06, Alexander Potapenko wrote:
> Hi Chang, Thomas, Borislav,
>
> "x86/fpu/signal: Prepare for variable sigframe length" has presumably
> introduced an information leak to the userspace.
>
> According to https://elixir.bootlin.com/linux/v5.16-rc2/source/arch/x86/kernel/fpu/signal.c#L126,
> save_sw_bytes() only initializes the first 20 bytes of sw_bytes, but
> then the whole struct is copied to the userspace.

Yes, that clearly lacks a memset(0).

Thanks,

        tglx

  reply	other threads:[~2021-11-27 20:28 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-26 11:06 Potential information leak in save_xstate_epilog() Alexander Potapenko
2021-11-27 20:26 ` Thomas Gleixner [this message]
2021-12-06 18:35 ` Bae, Chang Seok

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