PROPOSAL: extend UNIX_INFO2 to mark existence of ACLs
jpeach at apple.com
Wed Jan 23 00:14:59 GMT 2008
On Jan 22, 2008, at 3:46 PM, Christopher R. Hertel wrote:
> Jeremy Allison wrote:
>> On Tue, Jan 22, 2008 at 05:16:14PM -0600, Steve French wrote:
>>> There are systems which support Unix Extensions but do not support
> Yep. I'm working with one such currently.
I intended that this bit would be set by any server that understood
the UNIX_INFO2 info level and had a concept of (on-disk) ACLs the went
further than a one-to-one mapping of the POSIX permissions bits.
From a client point of view, the bit is flagging whether there is any
more security information to fetch that isn't in the UNIX_INFO2
response. Whether the extra security information is a POSIX ACL or a
NT security descriptor doesn't mater all that much (ie. the server has
to unify these somehow anyway).
>> Then they would have a zero in the "POSIX ACL exists" bit :-)
> As I understand it, the goal is to return a flag indicating whether
> or not a
> Posix ACL (or similar Unixy ACL such as an NFSv4 ACL) exists
> natively in the
> underlying file system on the server side. This ACL would only be
> used with
> the Unix extensions, and would provide Unix/Posix semantics.
> The proposal is to overload the Permissions field in the structure
> by the UNIX_INFO2 call.
No, it's to define an extra bit in this field. The extra bit means
"there are security attributes that aren't represented here".
#define UNIX_EXTENDED_SECURITY (1<<63) /* choose a less generic name! */
If a client sees this bit, it can query the security descriptor or
fetch the POSIX ACL, whichever it prefers. I expect that most clients
that support the UNIX extensions would simply fetch the ACL.
> Let me know how far off base I am.
> Shame there aren't any "reserved" fields in the return block.
> Chris -)-----
> "Implementing CIFS - the Common Internet FileSystem" ISBN:
> Samba Team -- http://www.samba.org/ -)----- Christopher R.
> jCIFS Team -- http://jcifs.samba.org/ -)----- ubiqx development,
> ubiqx Team -- http://www.ubiqx.org/ -)----- crh at ubiqx.mn.org
> OnLineBook -- http://ubiqx.org/cifs/ -)----- crh at ubiqx.org
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