Re: [PATCH v2 2/3] arm64: Add seccomp support

From: Will Deacon
Date: Thu Mar 06 2014 - 10:25:42 EST


On Thu, Mar 06, 2014 at 02:34:46AM +0000, AKASHI Takahiro wrote:
> On 03/01/2014 02:20 AM, Will Deacon wrote:
> > On Tue, Feb 25, 2014 at 09:20:24AM +0000, AKASHI Takahiro wrote:
> > I'm slightly surprised that we do the secure computing check first. Doesn't
> > this allow a debugger to change the syscall to something else after we've
> > decided that it's ok?
>
> To be honest, I just followed other architectures' implementation.
> Can you elaborate any use case that you have in your mind?

My initial thought was that we should do the secure_computing check *after*
the debugger has finished messing around with the registers. However, I
suppose you'd have had to enable ptrace in your seccompd filter for that
scenario to occur, so there's probably not an issue here after all.

Will
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