Hi Douglas:
My research shows that access denied conditional ACE is only valid when
AppLocker check the access. In case of file system, the access denied
conditional ACE is not evaluated.
I would like to add that by using the conditional access allowed ACE, access
denied can be simulated by crafting the right condition.
Please let me know if this does not answer your question.
I will file a bug against MS-DTYP.
Regards,
Obaid Farooqi
Escalation Engineer | Microsoft
-----Original Message-----
From: Obaid Farooqi
Sent: Tuesday, May 7, 2024 4:11 PM
To: Douglas Bagnall <douglas.bagn...@catalyst.net.nz>
Cc: Microsoft Support <supportm...@microsoft.com>; cifs-protocol@lists.samba.org
Subject: RE: [EXTERNAL] Re: conditional deny aces not working over SMB -
TrackingID#2405070040013300
Hi Douglas:
I'll look into this and will be in touch as soon as I have something to share.
Regards,
Obaid Farooqi
Escalation Engineer | Microsoft
-----Original Message-----
From: Douglas Bagnall <douglas.bagn...@catalyst.net.nz>
Sent: Monday, May 6, 2024 5:54 PM
To: Obaid Farooqi <oba...@microsoft.com>; cifs-protocol@lists.samba.org
Cc: Microsoft Support <supportm...@microsoft.com>
Subject: Re: [EXTERNAL] Re: conditional deny aces not working over SMB -
TrackingID#2310190040000571
hi Obaid,
Sorry for the long delay.
I have not been able to change the behaviour I reported, which is that an ACL
with a conditional deny ACE will not deny access over SMB, while the
corresponding conditional allow ACE does allow access. This seems to be
independent of whether claims are enabled.
This ACL doesn't depend on claims, as the condition refers to things that are
already known:
D:(XD;;FA;;;WD;(Member_of SID(WD)))(A;;FA;;;WD)
and it doesn't deny access. This ACL:
D:(XA;;FA;;;WD;(Member_of SID(WD)))
does allow access over SMB.
I think that's the out-of-the-box behaviour, and I haven't managed to find a
way of changing that by enabling claims.
I don't see documentation in MS-DTYP (or anywhere else) of where the various
ACE types have meaning.
My suspicion is that the kernel/NTFS has a partial implementation of
conditional ACEs, and that is what SMB uses. The documentation follows the
userspace API used by AD. It would be nice if the docs said "you can't use this
ACE type in protocol x", if that was actually true.
Douglas
On 9/11/23 18:12, Obaid Farooqi wrote:
> Hi Douglas:
> I assume the following link is working. If you have any other questions,
> please let me know.
>
> Regards,
> Obaid Farooqi
> Escalation Engineer | Microsoft
>
> -----Original Message-----
> From: Obaid Farooqi
> Sent: Wednesday, October 25, 2023 5:03 PM
> To: Douglas Bagnall <douglas.bagn...@catalyst.net.nz>;
> cifs-protocol@lists.samba.org
> Cc: Microsoft Support <supportm...@microsoft.com>
> Subject: RE: [EXTERNAL] Re: conditional deny aces not working over SMB
> - TrackingID#2310190040000571
>
> Hi Douglas:
> See if this works for you:
>
> https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Flear
> n.microsoft.com%2Fen-us%2Fwindows-server%2Fidentity%2Fsolution-guides%
> 2Fdeploy-a-central-access-policy--demonstration-steps-&data=05%7C02%7C
> obaidf%40microsoft.com%7Cb4632aa434f04f5d92da08dc6e1f6ae5%7C72f988bf86
> f141af91ab2d7cd011db47%7C1%7C0%7C638506328428497474%7CUnknown%7CTWFpbG
> Zsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%
> 3D%7C0%7C%7C%7C&sdata=2wse6ZBzv0vancJEI47JvvSWLNp1GgLUuskqN2iUP2A%3D&r
> eserved=0
>
> -----Original Message-----
> From: Douglas Bagnall <douglas.bagn...@catalyst.net.nz>
> Sent: Wednesday, October 25, 2023 3:34 PM
> To: Obaid Farooqi <oba...@microsoft.com>;
> cifs-protocol@lists.samba.org
> Cc: Microsoft Support <supportm...@microsoft.com>
> Subject: [EXTERNAL] Re: conditional deny aces not working over SMB -
> TrackingID#2310190040000571
>
> hi Obaid,
>
>> How did you set up you test environment?
>
> Well, haphazardly, it must be said. I tried various things, none of which
> made any difference.
>
> This is on a standalone server -- there is no KDC or user claims. The
> conditional ACEs refer to facts that are independent of actual claims, or
> only to resource attribute claims. They work perfectly with allow aces, and
> not at all with deny aces.
>
> I get a 404 at
> https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Flear
> n.microsoft.com%2Fen-us%2Fwindows-server%2Fidentity%2Fsolution-guides%
> 2Fdeploy-a-central-access-policy--demonstration-steps-&data=05%7C02%7C
> obaidf%40microsoft.com%7Cb4632aa434f04f5d92da08dc6e1f6ae5%7C72f988bf86
> f141af91ab2d7cd011db47%7C1%7C0%7C638506328428505944%7CUnknown%7CTWFpbG
> Zsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%
> 3D%7C0%7C%7C%7C&sdata=wtZNaoHYlMQOo3idzP3JU%2BoSRiGrvnkQys03IiSng7Y%3D
> &reserved=0
> -- was something clipped off the end?
>
> cheers,
> Douglas
>
> On 26/10/23 06:06, Obaid Farooqi wrote:
>> Hi Douglas:
>> My conversation with product group revealed that the claims based
>> authorization was developed to protect files, SMB or otherwise.
>> How did you set up you test environment?
>> Here is some instructions on setting up a test environment:
>>
>> https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Flea
>> r%2F&data=05%7C02%7Cobaidf%40microsoft.com%7Cb4632aa434f04f5d92da08dc
>> 6e1f6ae5%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C638506328428511
>> 738%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBT
>> iI6Ik1haWwiLCJXVCI6Mn0%3D%7C0%7C%7C%7C&sdata=S1AbxIQTPDS6WxrgVOVAfLvM
>> ZTZMYGadMErftCgVRgI%3D&reserved=0
>> n.microsoft.com%2Fen-us%2Fwindows-server%2Fidentity%2Fsolution-guides
>> %
>> 2Fdeploy-a-central-access-policy--demonstration-steps-&data=05%7C01%7
>> C
>> obaidf%40microsoft.com%7C0bd1e9e1373a4a3f7ec808dbd599b868%7C72f988bf8
>> 6
>> f141af91ab2d7cd011db47%7C1%7C0%7C638338628439791154%7CUnknown%7CTWFpb
>> G
>> Zsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0
>> %
>> 3D%7C3000%7C%7C%7C&sdata=DxCSvjNw1pNZHxqFc7O6Qo%2F%2BxB%2BTB2fMBk%2Fc
>> 4
>> 45PtZA%3D&reserved=0
>>
>> Regards,
>> Obaid Farooqi
>> Escalation Engineer | Microsoft
>>
>> -----Original Message-----
>> From: Obaid Farooqi
>> Sent: Thursday, October 19, 2023 11:45 AM
>> To: Jeff McCashland (He/him) <je...@microsoft.com>; Douglas Bagnall
>> <douglas.bagn...@catalyst.net.nz>; cifs-protocol@lists.samba.org
>> Cc: Microsoft Support <supportm...@microsoft.com>
>> Subject: RE: [EXTERNAL] conditional deny aces not working over SMB -
>> TrackingID#2310190040000571
>>
>> Hi Douglas:
>> I'll look into this and will be in touch as soon as I have an answer.
>>
>> Regards,
>> Obaid Farooqi
>> Escalation Engineer | Microsoft
>>
>> -----Original Message-----
>> From: Jeff McCashland (He/him) <je...@microsoft.com>
>> Sent: Wednesday, October 18, 2023 8:45 PM
>> To: Douglas Bagnall <douglas.bagn...@catalyst.net.nz>;
>> cifs-protocol@lists.samba.org
>> Cc: Microsoft Support <supportm...@microsoft.com>
>> Subject: RE: [EXTERNAL] conditional deny aces not working over SMB -
>> TrackingID#2310190040000571
>>
>> [DocHelp to BCC, support on CC, SR ID on Subject]
>>
>> Hi Douglas,
>>
>> Thank you for your email. We have created SR 2310190040000571 to track this
>> issue. One of our engineers will respond soon.
>>
>> Best regards,
>> Jeff McCashland (He/him) | Senior Escalation Engineer | Microsoft
>> Protocol Open Specifications Team
>> Phone: +1 (425) 703-8300 x38300 | Hours: 9am-5pm | Time zone:
>> (UTC-08:00) Pacific Time (US and Canada) Local country phone number
>> found here:
>> https://nam06.safelinks.protection.outlook.com/?url=http%3A%2F%2Fsupp
>> o%2F&data=05%7C02%7Cobaidf%40microsoft.com%7Cb4632aa434f04f5d92da08dc
>> 6e1f6ae5%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C638506328428515
>> 886%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBT
>> iI6Ik1haWwiLCJXVCI6Mn0%3D%7C0%7C%7C%7C&sdata=q9zXGo0JGX%2B6EsHE9FrD8s
>> G3ogEEH360lxAuknWZp6g%3D&reserved=0
>> rt.microsoft.com%2Fglobalenglish&data=05%7C01%7Cobaidf%40microsoft.co
>> m
>> %7C0bd1e9e1373a4a3f7ec808dbd599b868%7C72f988bf86f141af91ab2d7cd011db4
>> 7
>> %7C1%7C0%7C638338628439798155%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjA
>> w
>> MDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sd
>> a
>> ta=Y8ky%2Bi1gCFLBh8TzWSaTtjtGoY7wS28J%2BSFRojeiA4Q%3D&reserved=0 |
>> Extension 1138300
>>
>> -----Original Message-----
>> From: Douglas Bagnall <douglas.bagn...@catalyst.net.nz>
>> Sent: Wednesday, October 18, 2023 3:46 PM
>> To: cifs-protocol@lists.samba.org; Interoperability Documentation
>> Help <doch...@microsoft.com>
>> Subject: [EXTERNAL] conditional deny aces not working over SMB
>>
>> hi Dochelp,
>>
>> Using SMB2 and Windows 2022, if I set the DACL of a file to
>>
>> D:(XD;;FA;;;WD;(Member_of SID(WD)))(A;;FA;;;WD)
>>
>> I can still access the file (also over SMB2).
>>
>> I didn't expect that, as the first ACE should deny access when the condition
>> "Member_of SID(WD)" is true, which is essentially the same condition as the
>> allow ACE that follows it.
>>
>> I haven't been able to find any cases of conditional deny ACEs working for
>> file access. I see the same behaviour locally on the machine.
>>
>> I'm guessing this is out of scope for [MS-DTYP], which describes the ACE
>> types but does not say where and how they are used. Is the expected meaning
>> of conditional ACEs for file access described anywhere?
>>
>> From what I can see, conditional ACEs in file system is called Dynamic
>> Access Control, and people wrote everything that is known about it in 2012.
>>
>> I believe SMB defers the authorization decisions to the underlying file
>> system, and this uses something other than the user space AuthZ API which is
>> used for handling AD claims (I think). Most of what is written about
>> conditional ACEs refers to that API, or directly to claims.
>>
>> Because file system behaviour is not considered part of a protocol, ACLs on
>> files can be interpreted however the server prefers. Is that roughly the
>> position? On the slight chance it isn't, I would like to know if the
>> behaviour of conditional ACEs over SMB is documented.
>>
>> cheers,
>> Douglas
>>
>
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