[Bug 159557] NFSv3 in Gutsy maps uids wrongly

gcc chris+ubuntu at qwirx.com
Fri Nov 2 16:25:42 UTC 2007

Public bug reported:

Binary package hint: linux-generic

Mounting an NFS share from a FC2 server:

  /home 10.0.156.*(rw,async,no_root_squash) (client) is edgy (2.6.17-12-generic) and appears to work.
/etc/fstab has:

  server:/home /home nfs rw,soft,intr 0 0

This machine can access NFS home dirs just fine. It appears to be using
NFSv3, from nfsstat. (client) is gutsy (2.6.22-14-generic) and NFSv3 appears to
be broken. Cannot write to any files except in world-writable
directories, and the uid/gid is set to -2 always, like all_squash was in
effect, but this is done by the _client_.

pcap from edgy (attached):

15:53:52.761340 IP (tos 0x0, ttl 64, id 61342, offset 0, flags [DF],
proto TCP (6), length 240) >
188 create fh

pcap from gutsy (attached):

15:51:58.818008 IP (tos 0x0, ttl 64, id 63870, offset 0, flags [DF],
proto TCP (6), length 324) >
reply ok 272 create fh
REG 100644 ids -2/-2 sz 0

In both cases it's creating a file in a world-writable directory. Gutsy
uses the wrong permissions.

Forcing gutsy to use nfsv2 by mounting with nfsvers=2 option appears to
work around the problem.

This may be a security issue because users can create files with
uids/gids other than their own the nobody uid/gid).

I can try an alternative kernel but please post a direct HTTP link to
download it.

** Affects: linux-meta (Ubuntu)
     Importance: Undecided
         Status: New

NFSv3 in Gutsy maps uids wrongly
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