samba - Sep 2014 - Alternative data stream on volume cannot be created

Hello,

 

I met an issue to create ADS on a volume to store meta info.

A Samba server on Ubuntu is configured as follows to provide a share for
Windows client.  

 

OS: Ubuntu 14.04.1 LTS.

SAMBA: Version 4.1.6-Ubuntu

Kernel: 3.13.0-34-generic

 

The policy is as follows,

 

[Share]

path = /home/daniel/Public/sharefolder1

read only = no

browseable = yes

guest ok = no

create mask = 0777

directory mask = 0777

vfs objects = streams_xattr

 

On Win7 64bit client, I opened a console to test and got  the following
results:

 

1. File data stream can be created.

 

echo "sdfsdfc' > \\Server\Share\file:MetaInfo

 

Where Server is the computer name of the Ubuntu  machine; file is an
existing file name.. 

 

The command  succeeds.

 

 

2. Folder data stream can be created .

 

echo "sdfds" > \\Server\Share\fold\:MetaInfo

 

Where fold is an existing  directory name.

 

It succeeds as well.

 

 

3. Volume data stream cannot be created.

 

echo "dfvddfv" > \\Server\Share\:MetaInfo

 

It fails with an error message: The system cannot find the file
specified.

 

I tested on a  network folder shared  by windows machine, the volume
data stream can be created.

 

 

Is this the limitation of Linux Samba share?

 

Could anybody help me with this?

 

Thanks!

On Thu, Sep 11, 2014 at 05:53:39PM -0400, Tao Sang
wrote:
> Hello,
> 
>  
> 
> I met an issue to create ADS on a volume to store meta info.
> 
> A Samba server on Ubuntu is configured as follows to provide a share for
> Windows client.  
> 
>  
> 
> OS: Ubuntu 14.04.1 LTS.
> 
> SAMBA: Version 4.1.6-Ubuntu
> 
> Kernel: 3.13.0-34-generic
> 
>  
> 
> The policy is as follows,
> 
>  
> 
> [Share]
> 
> path = /home/daniel/Public/sharefolder1
> 
> read only = no
> 
> browseable = yes
> 
> guest ok = no
> 
> create mask = 0777
> 
> directory mask = 0777
> 
> vfs objects = streams_xattr
> 
>  
> 
> On Win7 64bit client, I opened a console to test and got  the following
> results:
> 
>  
> 
> 1. File data stream can be created.
> 
>  
> 
> echo "sdfsdfc' > \\Server\Share\file:MetaInfo
> 
>  
> 
> Where Server is the computer name of the Ubuntu  machine; file is an
> existing file name.. 
> 
>  
> 
> The command  succeeds.
> 
>  
> 
>  
> 
> 2. Folder data stream can be created .
> 
>  
> 
> echo "sdfds" > \\Server\Share\fold\:MetaInfo
> 
>  
> 
> Where fold is an existing  directory name.
> 
>  
> 
> It succeeds as well.
> 
>  
> 
>  
> 
> 3. Volume data stream cannot be created.
> 
>  
> 
> echo "dfvddfv" > \\Server\Share\:MetaInfo
> 
>  
> 
> It fails with an error message: The system cannot find the file
> specified.
> 
>  
> 
> I tested on a  network folder shared  by windows machine, the volume
> data stream can be created.
I'm guessing you're creating an ADS on the '.' directory
of the share. Can you post a wireshark trace of this
succeeding Windows -> Windows so we can investigate ?

Thanks,

Jeremy.