Message-ID: <6939adfb-ce2c-1911-19ee-af32f7d9a5ca@kernel.dk>
Date:   Thu, 9 Feb 2023 17:15:53 -0700
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:102.0) Gecko/20100101
 Thunderbird/102.7.1
Subject: Re: [PATCH v2] io_uring,audit: don't log IORING_OP_MADVISE
Content-Language: en-US
To:     Steve Grubb <sgrubb@redhat.com>,
        Richard Guy Briggs <rgb@redhat.com>,
        Paul Moore <paul@paul-moore.com>
Cc:     Linux-Audit Mailing List <linux-audit@redhat.com>,
        LKML <linux-kernel@vger.kernel.org>, io-uring@vger.kernel.org,
        Eric Paris <eparis@parisplace.org>,
        Christian Brauner <brauner@kernel.org>,
        Stefan Roesch <shr@fb.com>
References: <b5dfdcd541115c86dbc774aa9dd502c964849c5f.1675282642.git.rgb@redhat.com>
 <Y+VrSLZKZoAGikUS@madcap2.tricolour.ca>
 <CAHC9VhTNb4gOpk9=49-ABtYs1DFKqqwXPSc-2bhJX7wcZ82o=g@mail.gmail.com>
 <13293926.uLZWGnKmhe@x2>
From:   Jens Axboe <axboe@kernel.dk>
In-Reply-To: <13293926.uLZWGnKmhe@x2>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Precedence: bulk

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@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@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.

-- 
Jens Axboe