[PATCH v2] io_uring,audit: don't log IORING_OP_MADVISE

[PATCH v2] io_uring,audit: don't log IORING_OP_MADVISE

[Richard Guy Briggs]

fadvise and madvise both provide hints for caching or access pattern for
file and memory respectively.  Skip them.

Fixes: 5bd2182d58e9 ("audit,io_uring,io-wq: add some basic audit support to io_uring")
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
---
changelog
v2:
- drop *GETXATTR patch
- drop FADVISE hunk

 io_uring/opdef.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/io_uring/opdef.c b/io_uring/opdef.c
index 3aa0d65c50e3..d3f36c633ceb 100644
--- a/io_uring/opdef.c
+++ b/io_uring/opdef.c
@@ -312,6 +312,7 @@ const struct io_op_def io_op_defs[] = {
 		.issue			= io_fadvise,
 	},
 	[IORING_OP_MADVISE] = {
+		.audit_skip		= 1,
 		.name			= "MADVISE",
 		.prep			= io_madvise_prep,
 		.issue			= io_madvise,
-- 
2.27.0

--
Linux-audit mailing list
Linux-audit@redhat.com
https://listman.redhat.com/mailman/listinfo/linux-audit

Re: [PATCH v2] io_uring,audit: don't log IORING_OP_MADVISE

[Paul Moore]

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'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.

> Fixes: 5bd2182d58e9 ("audit,io_uring,io-wq: add some basic audit support to io_uring")
> Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> ---
> changelog
> v2:
> - drop *GETXATTR patch
> - drop FADVISE hunk
>
>  io_uring/opdef.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/io_uring/opdef.c b/io_uring/opdef.c
> index 3aa0d65c50e3..d3f36c633ceb 100644
> --- a/io_uring/opdef.c
> +++ b/io_uring/opdef.c
> @@ -312,6 +312,7 @@ const struct io_op_def io_op_defs[] = {
>                 .issue                  = io_fadvise,
>         },
>         [IORING_OP_MADVISE] = {
> +               .audit_skip             = 1,
>                 .name                   = "MADVISE",
>                 .prep                   = io_madvise_prep,
>                 .issue                  = io_madvise,
> --
> 2.27.0

-- 
paul-moore.com

--
Linux-audit mailing list
Linux-audit@redhat.com
https://listman.redhat.com/mailman/listinfo/linux-audit

Re: [PATCH v2] io_uring,audit: don't log IORING_OP_MADVISE

[Richard Guy Briggs]

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.

> 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.

> > Fixes: 5bd2182d58e9 ("audit,io_uring,io-wq: add some basic audit support to io_uring")
> > Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> > ---
> > changelog
> > v2:
> > - drop *GETXATTR patch
> > - drop FADVISE hunk
> >
> >  io_uring/opdef.c | 1 +
> >  1 file changed, 1 insertion(+)
> >
> > diff --git a/io_uring/opdef.c b/io_uring/opdef.c
> > index 3aa0d65c50e3..d3f36c633ceb 100644
> > --- a/io_uring/opdef.c
> > +++ b/io_uring/opdef.c
> > @@ -312,6 +312,7 @@ const struct io_op_def io_op_defs[] = {
> >                 .issue                  = io_fadvise,
> >         },
> >         [IORING_OP_MADVISE] = {
> > +               .audit_skip             = 1,
> >                 .name                   = "MADVISE",
> >                 .prep                   = io_madvise_prep,
> >                 .issue                  = io_madvise,
> > --
> > 2.27.0
> 
> -- 
> paul-moore.com
> 

- RGB

--
Richard Guy Briggs <rgb@redhat.com>
Sr. S/W Engineer, Kernel Security, Base Operating Systems
Remote, Ottawa, Red Hat Canada
IRC: rgb, SunRaycer
Voice: +1.647.777.2635, Internal: (81) 32635
--
Linux-audit mailing list
Linux-audit@redhat.com
https://listman.redhat.com/mailman/listinfo/linux-audit

Re: [PATCH v2] io_uring,audit: don't log IORING_OP_MADVISE

[Paul Moore]

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.

-- 
paul-moore.com

--
Linux-audit mailing list
Linux-audit@redhat.com
https://listman.redhat.com/mailman/listinfo/linux-audit

Re: [PATCH v2] io_uring,audit: don't log IORING_OP_MADVISE

[Steve Grubb]

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.

-Steve


--
Linux-audit mailing list
Linux-audit@redhat.com
https://listman.redhat.com/mailman/listinfo/linux-audit

Re: [PATCH v2] io_uring,audit: don't log IORING_OP_MADVISE

[Jens Axboe]

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


--
Linux-audit mailing list
Linux-audit@redhat.com
https://listman.redhat.com/mailman/listinfo/linux-audit

Re: [PATCH v2] io_uring,audit: don't log IORING_OP_MADVISE

[Paul Moore]

On Thu, Feb 9, 2023 at 7:15 PM Jens Axboe <axboe@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@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.

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

--
Linux-audit mailing list
Linux-audit@redhat.com
https://listman.redhat.com/mailman/listinfo/linux-audit

Re: [PATCH v2] io_uring,audit: don't log IORING_OP_MADVISE

[Jens Axboe]

On 2/10/23 8:39?AM, Paul Moore wrote:
> On Thu, Feb 9, 2023 at 7:15 PM Jens Axboe <axboe@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@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.
> 
> 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 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.

-- 
Jens Axboe

--
Linux-audit mailing list
Linux-audit@redhat.com
https://listman.redhat.com/mailman/listinfo/linux-audit

Re: [PATCH v2] io_uring,audit: don't log IORING_OP_MADVISE

[Paul Moore]

On Fri, Feb 10, 2023 at 11:00 AM Jens Axboe <axboe@kernel.dk> wrote:
> On 2/10/23 8:39?AM, Paul Moore wrote:
> > On Thu, Feb 9, 2023 at 7:15 PM Jens Axboe <axboe@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@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.
> >
> > 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@vger 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.

-- 
paul-moore.com

--
Linux-audit mailing list
Linux-audit@redhat.com
https://listman.redhat.com/mailman/listinfo/linux-audit

Re: [PATCH v2] io_uring,audit: don't log IORING_OP_MADVISE

[Richard Guy Briggs]

On 2023-02-10 11:52, Paul Moore wrote:
> On Fri, Feb 10, 2023 at 11:00 AM Jens Axboe <axboe@kernel.dk> wrote:
> > On 2/10/23 8:39?AM, Paul Moore wrote:
> > > On Thu, Feb 9, 2023 at 7:15 PM Jens Axboe <axboe@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@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.
> > >
> > > 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@vger 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.

> paul-moore.com

- RGB

--
Richard Guy Briggs <rgb@redhat.com>
Sr. S/W Engineer, Kernel Security, Base Operating Systems
Remote, Ottawa, Red Hat Canada
IRC: rgb, SunRaycer
Voice: +1.647.777.2635, Internal: (81) 32635
--
Linux-audit mailing list
Linux-audit@redhat.com
https://listman.redhat.com/mailman/listinfo/linux-audit

Re: [PATCH v2] io_uring,audit: don't log IORING_OP_MADVISE

[Paul Moore]

On Fri, Feb 10, 2023 at 5:00 PM Richard Guy Briggs <rgb@redhat.com> wrote:
> On 2023-02-10 11:52, Paul Moore wrote:
> > On Fri, Feb 10, 2023 at 11:00 AM Jens Axboe <axboe@kernel.dk> wrote:
> > > On 2/10/23 8:39?AM, Paul Moore wrote:
> > > > On Thu, Feb 9, 2023 at 7:15 PM Jens Axboe <axboe@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@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.
> > > >
> > > > 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@vger 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@paul-moore.com>

... if it's not on top of the tree, it's not worth popping patches to
add the ACK IMHO.

Feel free to reply to this Richard if you want to have the last word
in this thread, I think I'm done ;)

-- 
paul-moore.com

--
Linux-audit mailing list
Linux-audit@redhat.com
https://listman.redhat.com/mailman/listinfo/linux-audit

Re: [PATCH v2] io_uring,audit: don't log IORING_OP_MADVISE

[Paul Moore]

On Thu, Feb 9, 2023 at 5:54 PM Steve Grubb <sgrubb@redhat.com> 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.

Asking that a patch author does the proper level of due diligence to
ensure that the patch they are submitting is correct isn't being
"unnecessarily hard", it's part of being a good code reviewer and
maintainer.  I'm a bit amazed that you and Richard would rather spend
your time arguing about this rather than spending the hour (?) it
would take to verify the change and make a proper statement about the
correctness of the patch.

> 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.

You can't rely on grep, you need to chase the code paths to see what
code might be exercised.  For example, look at the truncate syscalls
(truncate, truncate64, ftruncate64, etc.), if you grep through the
SELinux hook code looking for some form of "truncate" you will not
find anything relevant; SELinux doesn't provide implementations for
either the security_file_truncate() or security_path_truncate() hooks.
However, if you follow the syscall code paths you will see that the
truncate syscalls end up calling security_inode_permission() which
*is* implemented in SELinux.

You need to do your homework; relying only on a gut feeling, a few
lines from a manpage, or a code comment is a good way to introduce
bugs.

-- 
paul-moore.com

--
Linux-audit mailing list
Linux-audit@redhat.com
https://listman.redhat.com/mailman/listinfo/linux-audit

Re: [PATCH v2] io_uring,audit: don't log IORING_OP_MADVISE

[Jens Axboe]

On Wed, 01 Feb 2023 15:33:33 -0500, Richard Guy Briggs wrote:
> fadvise and madvise both provide hints for caching or access pattern for
> file and memory respectively.  Skip them.
> 
> 

Applied, thanks!

[1/1] io_uring,audit: don't log IORING_OP_MADVISE
      commit: 2bd59885eb9c2094d118b4321d5f74e12e77ef0f

Best regards,
-- 
Jens Axboe



--
Linux-audit mailing list
Linux-audit@redhat.com
https://listman.redhat.com/mailman/listinfo/linux-audit