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    SubjectRe: [RFC PATCH 0/3] move the secure_computing call
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    On Thu, May 24, 2012 at 5:00 PM, Andrew Morton
    <akpm@linux-foundation.org> wrote:
    > On Thu, 24 May 2012 11:07:58 -0500
    > Will Drewry <wad@chromium.org> wrote:
    >
    >> This is an RFC based on the comments from Al Viro and Eric Paris
    >> regarding ptrace()rs being able to change the system call the kernel
    >> sees after the seccomp enforcement has occurred (for mode 1 or 2).
    >
    > Perhaps you could repeat those comments in this changelog.

    Oops :) Here's the context -- https://lkml.org/lkml/2012/5/21/326

    I doubt there's need for a repost though.

    >> With this series applied, a (p)tracer of a process with seccomp enabled
    >> will be unable to change the tracee's system call number after the
    >> secure computing check has been performed.
    >>
    >> The x86 change is tested, as is the seccomp.c change.  For other arches,
    >> it is not (RFC :).  Given that there are other inconsistencies in this
    >> code across architectures, I'm not sure if it makes sense to attempt to
    >> fix them all at once or to roll through as I attempt to add seccomp
    >> filter support.
    >>
    >> As is, the biggest benefit of this change is just setting consistent
    >> expectations in what the ptrace/seccomp interactions should be.  The
    >> current ability for ptrace to "bypass" secure computing (by remapping
    >> allowed system calls) is not necessarily a problem, but it is not
    >> necessarily intuitive behavior.
    >>
    >
    > Because my take on the above reasoning is "why did you bother writing
    > these patches"!

    Just to be thorough -- I wanted to make sure the discussion was framed
    against actual code just in case I was missing something. Otherwise,
    I'd be happy to see these patches disappear into the annals of the
    wayback machine.

    thanks!
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