Re: [PATCH 4/7] seccomp_filter: add process state reporting

[Will Drewry]

On Wed, Apr 27, 2011 at 10:40 PM, Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote:
> On Wed, Apr 27, 2011 at 10:24:20PM -0500, Will Drewry wrote:
>
>> Definitely.  Would it make sense to have /proc/<pid>/seccomp and
>> /proc/<pid>/seccomp_filter?
>
> Just one question: WTF bother with S_IRUSR?  Note that it's absolutely
> _useless_ in procfs; any kind of permission checks must be done in
> read(2) time since doing it in open(2) is worthless.  Consider execve()
> on suid binary; oops, there goes your uid and there goes the effect
> of checks done by open(2).  And if you *do* checks in read(2), why bother
> duplicating them in open(2)?

In earlier versions I was allowing filter/bitmask updating via the
proc file (which I nixed :).  Is S_IRUGO preferred? I don't see any
crazy information leakage by sharing the filters/ruleset.  I'll fold
it into the next version of this patch.

thanks!
will
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