Message-ID: <e6e8d984-2518-4790-cf0e-e39849607c49@kernel.dk>
Date:   Fri, 10 Feb 2023 16:01:39 -0700
From:   Jens Axboe <axboe@...nel.dk>
To:     Paul Moore <paul@...l-moore.com>,
        Richard Guy Briggs <rgb@...hat.com>
Cc:     Steve Grubb <sgrubb@...hat.com>,
        LKML <linux-kernel@...r.kernel.org>, io-uring@...r.kernel.org,
        Eric Paris <eparis@...isplace.org>,
        Christian Brauner <brauner@...nel.org>,
        Stefan Roesch <shr@...com>
Subject: Re: [PATCH v2] io_uring,audit: don't log IORING_OP_MADVISE

On 2/10/23 3:59 PM, Paul Moore wrote:
> On Fri, Feb 10, 2023 at 5:00 PM Richard Guy Briggs <rgb@...hat.com> wrote:
>> On 2023-02-10 11:52, Paul Moore wrote:
>>> On Fri, Feb 10, 2023 at 11:00 AM Jens Axboe <axboe@...nel.dk> wrote:
>>>> On 2/10/23 8:39?AM, Paul Moore wrote:
>>>>> On Thu, Feb 9, 2023 at 7:15 PM Jens Axboe <axboe@...nel.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@...hat.com> wrote:
>>>>>>>>> On 2023-02-01 16:18, Paul Moore wrote:
>>>>>>>>>> On Wed, Feb 1, 2023 at 3:34 PM Richard Guy Briggs <rgb@...hat.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.
>>>>
>>>> Maybe it isn't intended, but the replies have generally had a pretty
>>>> condescending tone to them. That's not the best way to engage folks, and
>>>> may very well be why people just kind of give up on it. Nobody likes
>>>> debating one-liners forever, particularly not if it isn't inviting.
>>>
>>> I appreciate that you are coming from a different space, but I stand
>>> by my comments.  Of course you are welcome to your own opinion, but I
>>> would encourage you to spend some time reading the audit mail archives
>>> going back a few years before you make comments like the above ... or
>>> not, that's your call; I recognize it is usually easier to criticize.
>>>
>>> On a quasi related note to the list/archives: unfortunately there was
>>> continued resistance to opening up the linux-audit list so I've setup
>>> audit@...r for upstream audit kernel work moving forward.  The list
>>> address in MAINTAINERS will get updated during the next merge window
>>> so hopefully some of the problems you had in the beginning of this
>>> discussion will be better in the future.
>>>
>>>>> I really would have preferred that you held off from merging this
>>>>> until this was resolved and ACK'd ... oh well.
>>>>
>>>> It's still top of tree. If you want to ack it, let me know and I'll add
>>>> it. If you want to nak it, give me something concrete to work off of.
>>>
>>> I can't in good conscience ACK it without some comment from Richard
>>> that he has traced the code paths; this shouldn't be surprising at
>>> this point.  I'm not going to NACK it or post a revert, I would have
>>> done that already if I felt that was appropriate.  Right now this
>>> patch is in a gray area for me in that I suspect it is good, but I
>>> can't ACK it without some comment that it has been properly
>>> researched.
>>
>> I feel a bit silly replying in this thread.  My dad claims that I need
>> to have the last word in any argument, so that way he gets it instead...
>>
>> I appear to have accidentally omitted the connector word "and" between
>> "description" and "code" above, which may have led you to doubt I had
>> gone back and re-looked at the code.
> 
> Okay, as long as you've done the homework on this I'm good.  If it's
> still on the top of Jen's tree, here's my ACK:
> 
> Acked-by: Paul Moore <paul@...l-moore.com>
> 
> ... if it's not on top of the tree, it's not worth popping patches to
> add the ACK IMHO.

Thanks - and it is, so I added the acked-by.

> Feel free to reply to this Richard if you want to have the last word
> in this thread, I think I'm done ;)
Let's close it up :-)

-- 
Jens Axboe

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