Re: CIFS regression mounting vers=1.0 NTLMSSP when hostname is too long

[Steven French]

makes sense - do you see anything related in the NTLMSSP doc?

Want to spin up a patch for SMB1 for this?

On 5/3/22 20:35, Paulo Alcantara wrote:
> Byron Stanoszek <gandalf@xxxxxxxxx> writes:
>
> > I would like to report a regression in the CIFS fs. Sometime between Linux 4.14
> > and 5.16, mounting CIFS with option vers=1.0 (and
> > CONFIG_CIFS_ALLOW_INSECURE_LEGACY=y set appropriately) with security type
> > NTLMSSP stopped working for me. The server side is a Windows 2003 Server.
> >
> > I found that this behavior depends on the length of the Linux client's
> > host+domain name (e.g. utsname()->nodename), where the mount works as long as
> > the name is 16 characters or less. Anything 17 or above returns -EIO, per the
> > following example:
> Looks like your server is expecting the WorkstationName field in
> AUTHENTICATE_MESSAGE payload to be 16 bytes long.  That is, NetBIOS name
> length as per rfc1001.
>
> > I implemented a workaround using the following patch:
> >
> > Signed-off-by: Byron Stanoszek <gandalf@xxxxxxxxx>
> > ---
> > --- a/fs/cifs/cifsglob.h
> > +++ b/fs/cifs/cifsglob.h
> > @@ -101,7 +101,7 @@
> >    #define XATTR_DOS_ATTRIB "user.DOSATTRIB"
> >    #endif
> >
> > -#define CIFS_MAX_WORKSTATION_LEN  (__NEW_UTS_LEN + 1)  /* reasonable max for client */
> > +#define CIFS_MAX_WORKSTATION_LEN 16
> >
> >    /*
> >     * CIFS vfs client Status information (based on what we know.)
> >
> > I don't know if this patch is correct or will have any real effect outside of
> > the NTLMSSP session connect sequence, but it worked in my case.
> Perhaps we should be use TCP_Server_Info::workstation_RFC1001_name in
> fs/cifs/sess.c:build_ntlmssp_auth_blob() instead only when connecting to
> old servers by using insecure dialects -- like SMB1, in your case.