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Date: Mon, 23 Jun 2014 09:46:09 +0100
From: Will Deacon <will.deacon@arm.com>
To: Kees Cook <keescook@chromium.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Russell King <linux@arm.linux.org.uk>,
        Andy Lutomirski <luto@amacapital.net>,
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	<linux-arm-kernel@lists.infradead.org>,
        Ricky Zhou <rickyz@google.com>
Subject: Re: [PATCH] arm: ptrace: fix syscall modification under
 PTRACE_O_TRACESECCOMP
Message-ID: <20140623084608.GA9316@arm.com>
References: <20140618202748.GA9022@www.outflux.net>
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 <20140620172330.GA30656@arm.com>
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On Fri, Jun 20, 2014 at 07:10:46PM +0100, Kees Cook wrote:
> On Fri, Jun 20, 2014 at 10:36 AM, Kees Cook <keescook@chromium.org> wrote:
> > On Fri, Jun 20, 2014 at 10:23 AM, Will Deacon <will.deacon@arm.com> wrote:
> >> Right, gotcha. Thanks for the explanation. I was confused, because
> >> tracehook_report_syscall does the right thing (returns
> >> current_thread_info()->syscall), but if we don't have TIF_SYSCALL_TRACE set,
> >> then updates during the secure_computing callback will be ignored.
> >>
> >> However, my fix to this is significantly smaller than your patch, so I fear
> >> I'm still missing something.
> >
> > Oh, yes, that's much smaller. Nice! I will test this and report back.
> 
> Yup, I can confirm this works. Thanks!
> 
> Tested-by: Kees Cook <keescook@chromium.org>

Thanks, Kees. I'll post a patch shortly. I'll try and remember to keep an
eye out for this when seccomp lands for arm64 too.

Will