From: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
To: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@kernel.org>, Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
"H. Peter Anvin" <hpa@zytor.com>,
Peter Zijlstra <peterz@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>,
Brian Gerst <brgerst@gmail.com>,
Chris Metcalf <cmetcalf@mellanox.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Huang Rui <ray.huang@amd.com>, Jiri Slaby <jslaby@suse.cz>,
Jonathan Corbet <corbet@lwn.net>,
"Michael S. Tsirkin" <mst@redhat.com>,
Paul Gortmaker <paul.gortmaker@windriver.com>,
Vlastimil Babka <vbabka@suse.cz>, Chen Yucong <slaoub@gmail.com>,
"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
Shuah Khan <shuah@kernel.org>,
linux-kernel@vg
Subject: Re: [PATCH v9 02/29] x86/boot: Relocate definition of the initial state of CR0
Date: Fri, 27 Oct 2017 12:02:19 -0700 [thread overview]
Message-ID: <20171027190219.GA7057@voyager> (raw)
In-Reply-To: <20171026125513.GB12068@nazgul.tnic>
On Thu, Oct 26, 2017 at 02:55:13PM +0200, Borislav Petkov wrote:
> On Thu, Oct 26, 2017 at 02:02:02AM -0700, Andy Lutomirski wrote:
> > I'm assuming that UMIP_REPORTED_CR0 will never change. If CR0 gets a
> > new field that we set some day, then I assume that CR0_STATE would add
> > that bit but UMIP_REPORTED_CR0 would not.
>
> Yeah, let's do that when it is actually needed.
Thanks Andy! I reasoned that for UMIP could report CR0_STATE a value that
is already revealed in the source code. Thus, if CR0 ever changes at run
time, an attacker could only see what is set programmatically.
BR,
Ricardo
WARNING: multiple messages have this Message-ID (diff)
From: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
To: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@kernel.org>, Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
"H. Peter Anvin" <hpa@zytor.com>,
Peter Zijlstra <peterz@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>,
Brian Gerst <brgerst@gmail.com>,
Chris Metcalf <cmetcalf@mellanox.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Huang Rui <ray.huang@amd.com>, Jiri Slaby <jslaby@suse.cz>,
Jonathan Corbet <corbet@lwn.net>,
"Michael S. Tsirkin" <mst@redhat.com>,
Paul Gortmaker <paul.gortmaker@windriver.com>,
Vlastimil Babka <vbabka@suse.cz>, Chen Yucong <slaoub@gmail.com>,
"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
Shuah Khan <shuah@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
X86 ML <x86@kernel.org>, "Neri, Ricardo" <ricardo.neri@intel.com>,
Dave Hansen <dave.hansen@intel.com>,
Denys Vlasenko <dvlasenk@redhat.com>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-arch <linux-arch@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>
Subject: Re: [PATCH v9 02/29] x86/boot: Relocate definition of the initial state of CR0
Date: Fri, 27 Oct 2017 12:02:19 -0700 [thread overview]
Message-ID: <20171027190219.GA7057@voyager> (raw)
Message-ID: <20171027190219.-_cad-cFCpmElwLNltBY6UxjGUcru2rGYLZQv9JlYdw@z> (raw)
In-Reply-To: <20171026125513.GB12068@nazgul.tnic>
On Thu, Oct 26, 2017 at 02:55:13PM +0200, Borislav Petkov wrote:
> On Thu, Oct 26, 2017 at 02:02:02AM -0700, Andy Lutomirski wrote:
> > I'm assuming that UMIP_REPORTED_CR0 will never change. If CR0 gets a
> > new field that we set some day, then I assume that CR0_STATE would add
> > that bit but UMIP_REPORTED_CR0 would not.
>
> Yeah, let's do that when it is actually needed.
Thanks Andy! I reasoned that for UMIP could report CR0_STATE a value that
is already revealed in the source code. Thus, if CR0 ever changes at run
time, an attacker could only see what is set programmatically.
BR,
Ricardo
next prev parent reply other threads:[~2017-10-27 19:03 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1507089272-32733-1-git-send-email-ricardo.neri-calderon@linux.intel.com>
2017-10-04 3:54 ` [PATCH v9 02/29] x86/boot: Relocate definition of the initial state of CR0 Ricardo Neri
2017-10-04 3:54 ` Ricardo Neri
2017-10-26 7:51 ` Andy Lutomirski
2017-10-26 7:51 ` Andy Lutomirski
2017-10-26 9:00 ` Borislav Petkov
2017-10-26 9:00 ` Borislav Petkov
2017-10-26 9:02 ` Andy Lutomirski
2017-10-26 9:02 ` Andy Lutomirski
2017-10-26 12:55 ` Borislav Petkov
2017-10-26 12:55 ` Borislav Petkov
2017-10-27 19:02 ` Ricardo Neri [this message]
2017-10-27 19:02 ` Ricardo Neri
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