[PATCH] arm: ptrace: fix syscall modification under PTRACE_O_TRACESECCOMP

[Kees Cook]

On Mon, Jun 23, 2014 at 1:46 AM, Will Deacon <will.deacon at arm.com> wrote:
> 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 at chromium.org> wrote:
>> > On Fri, Jun 20, 2014 at 10:23 AM, Will Deacon <will.deacon at 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 at 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.

Great, thanks!

What's the state of seccomp on arm64? I saw a series back in March,
but nothing since then? It looked complete, but I haven't set up a
test environment yet to verify.

-Kees

-- 
Kees Cook
Chrome OS Security