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Date:   Tue, 4 Oct 2022 11:30:55 +0300
From:   Mike Rapoport <rppt@kernel.org>
To:     Kees Cook <keescook@chromium.org>
Cc:     Rick Edgecombe <rick.p.edgecombe@intel.com>, x86@kernel.org,
        "H . Peter Anvin" <hpa@zytor.com>,
        Thomas Gleixner <tglx@linutronix.de>,
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        linux-arch@vger.kernel.org, linux-api@vger.kernel.org,
        Arnd Bergmann <arnd@arndb.de>,
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        Balbir Singh <bsingharora@gmail.com>,
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        Cyrill Gorcunov <gorcunov@gmail.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Eugene Syromiatnikov <esyr@redhat.com>,
        Florian Weimer <fweimer@redhat.com>,
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        dethoma@microsoft.com
Subject: Re: [PATCH v2 29/39] x86/cet/shstk: Support wrss for userspace
Message-ID: <YzvvPxkP3SDsNXG+@kernel.org>
References: <20220929222936.14584-1-rick.p.edgecombe@intel.com>
 <20220929222936.14584-30-rick.p.edgecombe@intel.com>
 <202210031525.78F3FA8@keescook>
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On Mon, Oct 03, 2022 at 03:28:47PM -0700, Kees Cook wrote:
> On Thu, Sep 29, 2022 at 03:29:26PM -0700, Rick Edgecombe wrote:
> > For the current shadow stack implementation, shadow stacks contents easily
> > be arbitrarily provisioned with data.
> 
> I can't parse this sentence.
> 
> > This property helps apps protect
> > themselves better, but also restricts any potential apps that may want to
> > do exotic things at the expense of a little security.
> 
> Is anything using this right now? Wouldn't thing be safer without WRSS?
> (Why can't we skip this patch?)

CRIU uses WRSS to restore the shadow stack contents.
 
> -- 
> Kees Cook

-- 
Sincerely yours,
Mike.