why can lstat fail? (was: Re: 1.5.7: nfs-server 2.2.47-2 troubles on XP)

[Baurjan Ismagulov <ibr at ata dot cs dot hun dot edu dot tr>]

Hello,

On Wed, Feb 04, 2004 at 04:41:28PM +0100, Baurjan Ismagulov wrote:
> I've installed cygwin snapshot 20030203 and run nfs-server-config. After
> starting the services, I cannot mount a directory with map_static:
> 
> linuxnfsclient:~# mount -o nolock 192.168.0.10:/etc /mnt
> mount: wrong fs type, bad option, bad superblock on 192.168.0.10:/etc,
>        or too many mounted filesystems

1. I haven't received any answer within a week. I would be very grateful
   if anyone having nfs mounts with proper owners and permissions shared
   his setup. Sam?

2. Ethereal shows that mountd authorizes the MOUNT call. After that the
   client calls GETATTR for /etc, which fails with ENOENT. Running
   rpc.nfsd as SYSTEM with -d all -F options reveals that lstat("/etc",
   ...) fails with ENOENT (line 106 of nfsd-SYSTEM.log; confirmed under
   gdb).

   The question: What makes lstat fail?

   Playing with owners and permissions hasn't given any results
   (perm-original.txt and perm-modified.txt).

   I've also seen that nfsd changes the effective user and group ids.
   Trying to reproduce the problem, I've written a.c, which works
   without problems with both original and modified permissions (2113
   corresponds to root. FWIW, it is disabled, which doesn't seem to
   matter). What else in nfsd could make lstat fail?

   I've also tried to run nfsd as a normal user. If I have "Create a
   token object" privilege (I think this was meant with "impersonate
   logged on user" right, mentioned in nfs-server-2.2.47-2.README), the
   daemon does the same, i.e., fails on lstat. If, however, I don't have
   this privilege, the daemon fails to seteuid and allows the client to
   access the filesystem; naturally, one can't write anything due to
   permissions.

Any help would be greatly appreciated. Thank you in advance.

With kind regards,
Baurjan.

Attachment: nfsd-SYSTEM.log
Description: Text document

Attachment: perm-original.txt
Description: Text document

Attachment: perm-modified.txt
Description: Text document

Attachment: a.c
Description: Text document

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