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.
