On Thu, Feb 9, 2023 at 7:15 PM Jens Axboe <axboe(a)kernel.dk> wrote:
 On 2/9/23 3:54 PM, Steve Grubb wrote:
 > On Thursday, February 9, 2023 5:37:22 PM EST Paul Moore wrote:
 >> On Thu, Feb 9, 2023 at 4:53 PM Richard Guy Briggs <rgb(a)redhat.com> wrote:
 >>> On 2023-02-01 16:18, Paul Moore wrote:
 >>>> On Wed, Feb 1, 2023 at 3:34 PM Richard Guy Briggs
<rgb(a)redhat.com>
 > wrote:
 >>>>> fadvise and madvise both provide hints for caching or access
pattern
 >>>>> for file and memory respectively.  Skip them.
 >>>>
 >>>> You forgot to update the first sentence in the commit description :/
 >>>
 >>> I didn't forget.  I updated that sentence to reflect the fact that the
 >>> two should be treated similarly rather than differently.
 >>
 >> Ooookay.  Can we at least agree that the commit description should be
 >> rephrased to make it clear that the patch only adjusts madvise?  Right
 >> now I read the commit description and it sounds like you are adjusting
 >> the behavior for both fadvise and madvise in this patch, which is not
 >> true.
 >>
 >>>> I'm still looking for some type of statement that you've done
some
 >>>> homework on the IORING_OP_MADVISE case to ensure that it doesn't
end
 >>>> up calling into the LSM, see my previous emails on this.  I need more
 >>>> than "Steve told me to do this".
 >>>>
 >>>> I basically just want to see that some care and thought has gone into
 >>>> this patch to verify it is correct and good.
 >>>
 >>> Steve suggested I look into a number of iouring ops.  I looked at the
 >>> description code and agreed that it wasn't necessary to audit madvise.
 >>> The rationale for fadvise was detemined to have been conflated with
 >>> fallocate and subsequently dropped.  Steve also suggested a number of
 >>> others and after investigation I decided that their current state was
 >>> correct.  *getxattr you've advised against, so it was dropped.  It
 >>> appears fewer modifications were necessary than originally suspected.
 >>
 >> My concern is that three of the four changes you initially proposed
 >> were rejected, which gives me pause about the fourth.  You mention
 >> that based on your reading of madvise's description you feel auditing
 >> isn't necessary - and you may be right - but based on our experience
 >> so far with this patchset I would like to hear that you have properly
 >> investigated all of the madvise code paths, and I would like that in
 >> the commit description.
 >
 > I think you're being unnecessarily hard on this. Yes, the commit message
 > might be touched up. But madvise is advisory in nature. It is not security
 > relevant. And a grep through the security directory doesn't turn up any
 > hooks.
 Agree, it's getting a bit anal... FWIW, patch looks fine to me. 
Call it whatever you want, but the details are often important at this
level of code, and when I see a patch author pushing back on verifying
that their patch is correct it makes me very skeptical.
I really would have preferred that you held off from merging this
until this was resolved and ACK'd ... oh well.
-- 
paul-moore.com