From mboxrd@z Thu Jan  1 00:00:00 1970
From: Marcelo Tosatti <mtosatti@redhat.com>
Subject: Re: [PATCH] kvm: x86: i8259: return initialized data on invalid-size
 read
Date: Thu, 12 Mar 2015 22:02:59 -0300
Message-ID: <20150313010259.GB17648@amt.cnet>
References: <20150311111609.GG8544@dhcp-25-225.brq.redhat.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
To: kvm <kvm@vger.kernel.org>, Paolo Bonzini <pbonzini@redhat.com>,
	Gleb Natapov <gleb@kernel.org>, nadav.amit@gmail.com
Return-path: <kvm-owner@vger.kernel.org>
Received: from mx1.redhat.com ([209.132.183.28]:44692 "EHLO mx1.redhat.com"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1752449AbbCMBDQ (ORCPT <rfc822;kvm@vger.kernel.org>);
	Thu, 12 Mar 2015 21:03:16 -0400
Content-Disposition: inline
In-Reply-To: <20150311111609.GG8544@dhcp-25-225.brq.redhat.com>
Sender: kvm-owner@vger.kernel.org
List-ID: <kvm.vger.kernel.org>

On Wed, Mar 11, 2015 at 12:16:09PM +0100, Petr Matousek wrote:
> If data is read from PIC with invalid access size, the return data stays
> uninitialized even though success is returned. 
> 
> Fix this by always initializing the data.
> 
> Signed-off-by: Petr Matousek <pmatouse@redhat.com>
> Reported-by: Nadav Amit <nadav.amit@gmail.com>
> ---
>  arch/x86/kvm/i8259.c |    1 +
>  1 files changed, 1 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/x86/kvm/i8259.c b/arch/x86/kvm/i8259.c
> index cc31f7c..9541ba3 100644
> --- a/arch/x86/kvm/i8259.c
> +++ b/arch/x86/kvm/i8259.c
> @@ -507,6 +507,7 @@ static int picdev_read(struct kvm_pic *s,
>  		return -EOPNOTSUPP;
>  
>  	if (len != 1) {
> +		memset(val, 0, len);
>  		pr_pic_unimpl("non byte read\n");
>  		return 0;
>  	}
> -- 
> 1.7.4.4

Applied, thanks.