CIFS version 1/2 negotiate ?

CIFS version 1/2 negotiate ?

[Tjernlund]

We got an old netapp server which exposes CIFS vers=1 and when trying to mount shares
from this netapp we get:
CIFS: VFS: \\netapp2 Dialect not supported by server. Consider  specifying vers=1.0 or vers=2.0 on mount for accessing older servers
CIFS: VFS: cifs_mount failed w/return code = -95

If I specify vers=1 manually on the mount cmd it works.
However, GUI file managers cannot handle this and less Linux savy users don't know how to
use the mount cmd manually.

I wonder if kernel could grow a SMB1 version negotiate so a standard CIFS mount can work?
We are at kernel 5.13 and I can test/use a kernel patch.

 Jocke

Re: CIFS version 1/2 negotiate ?

[ronnie sahlberg]

On Wed, Aug 25, 2021 at 9:49 PM Tjernlund <tjernlund@tjernlund.se> wrote:
>
> We got an old netapp server which exposes CIFS vers=1 and when trying to mount shares
> from this netapp we get:
> CIFS: VFS: \\netapp2 Dialect not supported by server. Consider  specifying vers=1.0 or vers=2.0 on mount for accessing older servers
> CIFS: VFS: cifs_mount failed w/return code = -95
>
> If I specify vers=1 manually on the mount cmd it works.
> However, GUI file managers cannot handle this and less Linux savy users don't know how to
> use the mount cmd manually.
>
> I wonder if kernel could grow a SMB1 version negotiate so a standard CIFS mount can work?
> We are at kernel 5.13 and I can test/use a kernel patch.

I don't think we can do that in the client.  We are all trying to move
away from SMB1, and a lot of servers already today
have it either disabled by default or even removed from the compile.
So enabling automatic multi-protocol support for SMB1 is the wrong
direction for us.

For that reason I think there will also be pushback from GUI
filemanagers to add a "smb1 tickbox", but you can try.

Other solutions could be to locally hack and replace mount.cifs with a
patch to "detect if servername matches the old netapp and
automatically add a vers=1 to the mount argument string passed to the
kernel".
It would require you to build a patched version of cifs-utils and
distribute to all the client machines though, so ...


>
>  Jocke
>
>

Re: CIFS version 1/2 negotiate ?

[Steve French]

On Thu, Aug 26, 2021 at 1:35 PM ronnie sahlberg
<ronniesahlberg@gmail.com> wrote:
>
> On Wed, Aug 25, 2021 at 9:49 PM Tjernlund <tjernlund@tjernlund.se> wrote:
> >
> > We got an old netapp server which exposes CIFS vers=1 and when trying to mount shares
> > from this netapp we get:
> > CIFS: VFS: \\netapp2 Dialect not supported by server. Consider  specifying vers=1.0 or vers=2.0 on mount for accessing older servers
> > CIFS: VFS: cifs_mount failed w/return code = -95
> >
> > If I specify vers=1 manually on the mount cmd it works.
> > However, GUI file managers cannot handle this and less Linux savy users don't know how to
> > use the mount cmd manually.
> >
> > I wonder if kernel could grow a SMB1 version negotiate so a standard CIFS mount can work?
> > We are at kernel 5.13 and I can test/use a kernel patch.
>
> I don't think we can do that in the client.  We are all trying to move
> away from SMB1, and a lot of servers already today
> have it either disabled by default or even removed from the compile.
> So enabling automatic multi-protocol support for SMB1 is the wrong
> direction for us.
>
> For that reason I think there will also be pushback from GUI
> filemanagers to add a "smb1 tickbox", but you can try.
>
> Other solutions could be to locally hack and replace mount.cifs with a
> patch to "detect if servername matches the old netapp and
> automatically add a vers=1 to the mount argument string passed to the
> kernel".
> It would require you to build a patched version of cifs-utils and
> distribute to all the client machines though, so ...
You could do a small mount.cifs pass through script that adds
"vers=1.0" and then calls the real mount.cifs ... might also be able
to put the mount options in /etc/fstab with vers=1.0

-- 
Thanks,

Steve