[Samba] Fwd: STATUS_ACCESS_DENIED with NTCreateAndX if Access Mask has System Security bit set

[Tom Lee]

---------- Forwarded message ----------
From: Tom Lee <tlee2951 at gmail.com>
Date: Mon, Feb 27, 2012 at 3:10 PM
Subject: Re: [Samba] STATUS_ACCESS_DENIED with NTCreateAndX if Access Mask
has System Security bit set
To: Jeremy Allison <jra at samba.org>


Jeremy thanks for your response.  I didn't actually build Samba from
sources I'm just running the version of Samba that comes with OpenSuse
v12.1 which is 3.6.1-34.3.1.x86_64 .

I'm pretty sure the chunk of code inside libcli/security/access_check.c you
mentioned is enabled with this version, since before I gave the
Administrator user SeSecurityPrivilege I was getting the
NT_STATUS_PRIVILEGE_NOT_HELD error, then once I granted the privilege that
error went away. But then I started getting the NT_STATUS_ACCESS_DENIED
coming from the check in open.c smbd_calculate_access_mask.

Please let me know if there is something else I should try or if you need
any additional info on my configuration. Thanks.


On Mon, Feb 27, 2012 at 2:44 PM, Jeremy Allison <jra at samba.org> wrote:

> On Fri, Feb 24, 2012 at 09:00:36AM -0700, Tom Lee wrote:
> > I've been trying to run a .NET app on Windows 2008 against a Samba v3.6.1
> > server running on OpenSuse x64 v12.1 but keep running into problems.
> >
> > What the .NET app is doing is trying to read the ACL for a directory
> using
> > UNC path pointing to a directory below the "users" share on the samba
> > server.   The app is running as user Administrator. On the samba side the
> > Administrator user has been given the following priviliges:
> >  SeSecurityPrivilege, SeRestorePrivilege, SeBackupPrivilege, and
> > SeTakeOwnershipPrivilege.
> >
> > Specifically the .NET/C# method call being made is below: In this case
> > srcFolderName is something like "\\SambaServer\users\Administrator":
> >
> > DirectorySecurity srcFolderSecurity =
> > Directory.GetAccessControl(srcFolderName,  AccessControlSections.All);
> >
> > Calling this method results in an Exception. I can see from a Wireshark
> > trace that the exception corresponds to an error being returned from a
> call
> > to NTCreateAndx for a user folder named "\Administrator" and Access Mask
> > set to 0x01020080. The bit that seems to cause problems when set is the
> > System Security bit (0x01000000).
> >
> > Originally before I had given user Administrator any privileges (using
> net
> > rpc rights grant...), the NTCreateAndX response error was
> > *STATUS_PRIVILEGE_NOT_HELD.
> >  After granting privileges the error changed to STATUS_ACCESS_DENIED. *
> > *
> > *
> > *Looking at the log.smbd with debugLevel = 10. I can see the following
> > relevant trace info:*
> > *
> > *
> > *
> > [2012/02/23 12:35:24.190992, 10]
> > smbd/open.c:1430(smbd_calculate_access_mask)
> >   smbd_calculate_access_mask: Access denied on file Administrator:
> rejected
> > by share access mask[0x101F01FF] orig[0x01020080] mapped[0x01020080]
> > reject[0x01000000]
> > [2012/02/23 12:35:24.191049, 10] smbd/open.c:1761(open_file_ntcreate)
> >   open_file_ntcreate: smbd_calculate_access_mask on file Administrator
> > returned NT_STATUS_ACCESS_DENIED
> > [2012/02/23 12:35:24.191107,  5] smbd/files.c:464(file_free)
> >   freed files structure 9877 (0 used)
> > [2012/02/23 12:35:24.191162, 10] smbd/open.c:3420(create_file_unixpath)
> >   create_file_unixpath: NT_STATUS_ACCESS_DENIED
> > [2012/02/23 12:35:24.191216, 10] smbd/open.c:3700(create_file_default)
> >   create_file: NT_STATUS_ACCESS_DENIED
>
> Ok, there is this chunk of code inside libcli/security/access_check.c
>
>        /* s3 had this with #if 0 previously. To be sure the merge
>           doesn't change any behaviour, we have the above #if check
>           on _SAMBA_BUILD_. */
>        if (access_desired & SEC_FLAG_SYSTEM_SECURITY) {
>                if (security_token_has_privilege(token, SEC_PRIV_SECURITY))
> {
>                        bits_remaining &= ~SEC_FLAG_SYSTEM_SECURITY;
>                } else {
>                        return NT_STATUS_PRIVILEGE_NOT_HELD;
>                }
>        }
>
> in the current v3-6-test git tree. Can you check if this is
> #ifdef'ed out in your code ?
>
> Jeremy.
>