Comment 0 for bug 1315974

In a previous Ubuntu upgrade to 13.10, there was a problem with AUTH_GSS timeouts on NFS v3 mount attempts slowing down NFSv3 mounting. Several workarounds existed, one of which was to explicitly list "sec=sys" as an /etc/fstab mount option.

The NFS server in this case is a NetGear ReadyNAS PRO running Debian, kernel: 2.6.37.6.RNx86_64.2.4 The NFS server is not involved in this problem, it is purely client side.

It appears there is a kernel fix somewhere around 3.12.7-2 for the original AUTH_GSS timeout problem causing the workaround.

On upgrade from from 13.04 to 13.10, NFSv3 mounts stop working if sec=sys is specified in /etc/fstab.

Specifically, the mount works, but access to files receive client side permission denial. Investigation showed that if the directory was mounted 777 and a test file was created, then the file had uid/gid nobody/nogroup instead of the expected client side UID/GID.

wireshark clearly showed that with sec=sys on the fstab options, the RPC credentials were AUTH_NULL. If sec=sys is removed from the fstab options, then RPC credentials are now AUTH_UNIX.

Repeat by:
- create /c/tmp directory mode 777 on NFS file server where /etc/password & groups are coordinated with the client
- export /c/tmp as insecure,insecure_locks,rw,async
- add directory to /etc/fstab, options auto,sec=sys,nfsvers=3:
  nas:/c/tmp /mnt nfs auto,sec=sys,nfsvers=3 0 0
- execute the following while conducting dumpcap:
  sudo mount /mnt
  touch /mnt/test
  ls -l /mnt/test
- observe file is nobody/nogroup
- observe RPC credentials are AUTH_NULL in wireshark
- remove sys=sec from fstab and repeat above.
- result will be correct uid/gid & RPC credentials of AUTH_UNIX

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: nfs-common 1:1.2.8-6ubuntu1
ProcVersionSignature: Ubuntu 3.13.0-24.46-generic 3.13.9
Uname: Linux 3.13.0-24-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.14.1-0ubuntu3
Architecture: amd64
CurrentDesktop: Unity
Date: Sun May 4 21:23:26 2014
InstallationDate: Installed on 2012-11-20 (530 days ago)
InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Release amd64 (20121017.5)
SourcePackage: nfs-utils
UpgradeStatus: Upgraded to trusty on 2014-04-19 (15 days ago)