[Samba] chdir_current_service: vfs_ChDir(/srv/samba/users) failed: Permission denied.

Anders Östling anders.ostling at gmail.com
Mon Nov 29 16:30:45 UTC 2021


This is gold and deserves it's own section/chapter in the Wiki. I have been
bitten more than once by this.

Anders

On Mon, Nov 29, 2021 at 5:03 PM L.P.H. van Belle via samba <
samba at lists.samba.org> wrote:

> what i see here :
>
> /srv is fine.
> -------------------
> /srv/samba not fully, its possible to use it like this.
> # flags: -s-  your setting Creator Group, its possible.
> other::--x  it allows traversal, but this is also before a share ping, you
> need read rights also.
> to be able to read the next folder. ( like users)
>
> so i have
>
> # file: srv/samba
> # owner: root
> # group: root
> # flags: s--
> user::rwx
> group::rwx
> other::r-x
>
> ----------------
> The users share is very different.
>
> what i really recommend..
>
> setup exactly as shown here.
>
> https://docs.microsoft.com/en-us/windows-server/storage/folder-redirection/deploy-folder-redirection
>
> When thats done, create 1 user in there and capture the settings with
> getfacl and samba-tools
> sudo samba-tool ntacl get /srv/samba/users/ --as-sddl
>
> Then is something goes wrong you can easy script it to fix it.
>
> So this is what i have.
>
> # file: srv/samba/users
> # owner: root
> # group: root
> # flags: -s-
> user::rwx
> user:root:rwx
> group::---
> group:root:---
> group:BUILTIN\\administrators:rwx
> group:BUILTIN\\users:r-x
> group:2007:rwx
> mask::rwx
> other::---
> default:user::rwx
> default:user:root:rwx
> default:group::---
> default:group:root:---
> default:group:BUILTIN\\administrators:rwx
> default:group:2007:rwx
> default:mask::rwx
> default:other::---
>
> (Domain Users is member of BUILTIN\\users. )
> (Domain Admins is member of BUILTIN\\Administrators. )
>
> wbinfo -G 2007  =  S-1-5-18
> wbinfo -s S-1-5-18  =  NT Authority\SYSTEM 5
>
> (Domain Users is member of BUILTIN\\users. )
>
>
> looking at your set.. i suspect this is the one thats wrong.
> group:domain\040users:---
>
> what i suggest, create a new share, dont change the share security.
> run this on the new test folder
> samba-tool ntacl set
> "O:LAG:S-1-22-2-0D:PAI(A;;0x001200a9;;;BU)(A;OICIIO;0x001f01ff;;;CO)(A;OICI;0x001f01ff;;;SY)(A;OICI;0x001f01ff;;;BA)"
> /srv/samba/users-test
>
> This is the following setting.
> security On the folder,  (via Advanced)
> Creator Owner, only on subfolders and files.
> SYSTEM Full control
> Administrators (Domain admins)  full control.
> Users (Domain users), Read and Exec, only this folder.
>
> Then run this
> TESTUSER=karen
> samba-tool ntacl set
> "O:S-1-22-1-0G:S-1-22-2-0D:AI(A;OICI;0x001301bf;;;$(wbinfo --name-to-sid
> "${TESTUSER}" |awk '{ print $1
> }'))(A;ID;0x001200a9;;;S-1-22-2-0)(A;OICIIOID;0x001200a9;;;CG)(A;OICIID;0x001f01ff;;;LA)(A;OICIID;0x001f01ff;;;DA)"
> /srv/samba/users/"${TESTUSER}"
>
> Now look at the rights from within windows on karen's folder.
>
>
> its is this setup.
>
> https://docs.microsoft.com/en-us/windows-server/storage/folder-redirection/deploy-folder-redirection
>
> the pittfall in that tekst is :
> Security group of users who need to put data on the share (Folder
> Redirection Users)
> Dont use domain users or everyone
>
> i use "Redirected Folder Users"
>
> I hope this helps a bit.
>
>
> Greetz,
>
> Louis
>
>
>
> ________________________________
>
>         Van: Roy Eastwood [mailto:spindles7 at gmail.com]
>         Verzonden: maandag 29 november 2021 11:21
>         Aan: L.P.H. van Belle; samba at lists.samba.org
>         Onderwerp: Re: [Samba] chdir_current_service:
> vfs_ChDir(/srv/samba/users) failed: Permission denied.
>
>
>         Ok, here are the results:
>
>         roy at lxd-m1:~$ sudo getfacl /srv
>         [sudo] password for roy:
>         getfacl: Removing leading '/' from absolute path names
>         # file: srv
>         # owner: root
>         # group: root
>         user::rwx
>         group::r-x
>         other::r-x
>
>
>         roy at lxd-m1:~$ sudo getfacl /srv/samba
>         getfacl: Removing leading '/' from absolute path names
>         # file: srv/samba
>         # owner: root
>         # group: domain\040admins
>         # flags: -s-
>         user::rwx
>         group::rwx
>         other::--x
>
>         roy at lxd-m1:~$ sudo getfacl /srv/samba/users
>         getfacl: Removing leading '/' from absolute path names
>         # file: srv/samba/users
>         # owner: root
>         # group: domain\040admins
>         user::rwx
>         user:root:rwx
>         user:domain\040admins:rwx
>         user:domain\040computers:r-x
>         group::rwx
>         group:NT\040Authority\\authenticated\040users:rwx
>         group:NT\040Authority\\system:rwx
>         group:domain\040admins:rwx
>         group:domain\040computers:r-x
>         mask::rwx
>         other::---
>         default:user::rwx
>         default:user:root:rwx
>         default:user:domain\040admins:rwx
>         default:group::---
>         default:group:NT\040Authority\\system:rwx
>         default:group:domain\040admins:rwx
>         default:mask::rwx
>         default:other::---
>
>
>         roy at lxd-m1:~$ sudo getfacl /srv/samba/users/karen
>         getfacl: Removing leading '/' from absolute path names
>         # file: srv/samba/users/karen
>         # owner: karen
>         # group: domain\040users
>         user::rwx
>         user:root:rwx
>         user:domain\040admins:rwx
>         group::---
>         group:NT\040Authority\\system:rwx
>         group:domain\040admins:rwx
>         group:domain\040users:---
>         group:karen:rwx
>         mask::rwx
>         other::---
>         default:user::rwx
>         default:user:root:rwx
>         default:user:domain\040admins:rwx
>         default:user:karen:rwx
>         default:group::---
>         default:group:NT\040Authority\\system:rwx
>         default:group:domain\040admins:rwx
>         default:group:domain\040users:---
>         default:group:karen:rwx
>         default:mask::rwx
>         default:other::---
>
>         Thanks for your help,
>         Roy
>
>         On Mon, 29 Nov 2021, 09:54 L.P.H. van Belle via samba, <
> samba at lists.samba.org> wrote:
>
>
>                 A full output of the created structure would be nice
>                 and helps to explain that.
>
>                 For all the used folders a getfacl should tell sufficent.
>                 getfacl /srv
>                 getfacl /srv/samba
>                 getfacl /srv/samba/users
>                 getfacl /srv/samba/users/username
>
>                 But i suspect "SYSTEM" is missing somewhere.
>                 And/Or did you change the Share Rights in Windows.
>                 Because, if you do that, AFTER users are created,
>                 it can mess up already existing folders and there rights.
>
>                 I work in this order.
>                 1) install samba.
>                 2) create the folders in /srv/samba and setup the shares.
>                 3) setup the share and folder fights.
>                 4) create users and set user home and profiles
>
>                 Greetz,
>
>                 Louis
>
>
>                 > -----Oorspronkelijk bericht-----
>                 > Van: samba [mailto:samba-bounces at lists.samba.org]
> Namens
>                 > spindles seven via samba
>                 > Verzonden: zondag 28 november 2021 0:41
>                 > Aan: samba at lists.samba.org
>                 > CC: 'Patrick Goetz'
>                 > Onderwerp: Re: [Samba] chdir_current_service:
>                 > vfs_ChDir(/srv/samba/users) failed: Permission denied.
>                 >
>                 > On 27 November 2021 20:05 Ralph Boehme wrote:
>                 > > On 11/27/21 18:27, Patrick Goetz via samba wrote:
>                 > > > Sure, but Samba, which runs are root,
>                 > >
>                 > > smbd does not run as root when executing SMB requests,
> it
>                 > impersonates
>                 > > the user UNIX token while doing this.
>                 > >
>                 > OK, that explains why one of my Domain Computers got
>                 > permission denied, but that raises the other question -
> why
>                 > then is a normal user able to access his/her files which
> live
>                 > in /srv/samba/users/<username> without any problem?
> The
>                 > permissions on /srv/samba (before I added the "x") was
>                 > rwxrwx--- : root and Domain Admins only have access.
>  So
>                 > Domain Users were able to traverse the hierarchy but not
>                 > Domain Computers.    Why?
>                 >
>                 > Thanks,
>                 >
>                 > Roy
>                 >
>                 >
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-- 
------ -------------------- 8 ------------------ ------
"A *wise* man once told me - Any idiot can do backups, but it takes a
genius to successfully restore"

Anders Östling
+46 768 716 165 (Mobil)
+46 431 45 56 01  (Hem)


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