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Today, one of my coworkers ran into trouble setting up a new intern to work. An account was set up by our IT group for the intern, but we were not able to access it. When I investigated, I found:

$ ls -ld /acct/c33408 drwxr-xr-x 1 root system 1 May 23 09:48 /acct/c33408 

Clearly the admin who set up the account forgot to change owner and group. However what puzzles me is that the account directory is shown as both readable and searchable by everyone. However when I attempt to see what is in it:

$ ls /acct/c33408 ls: /acct/c33408: The file access permissions do not allow the specified action. 

And similarly for trying to change to that directory.

Why will it not show me the contents of this directory when the permissions appear to allow it? I have checked and there is no ACL on this directory.

This is an AIX network, and the directory is on an NFS mount.

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  • The single-byte size reminds me of an automounter stub; is there an automounter involved? Commented May 23, 2018 at 15:58
  • @JeffSchaller - While that is outside my direct knowledge (I am just a user, so system architecture isn't anything I've gotten into), I believe so. Commented May 23, 2018 at 16:14
  • ps -ef and grep for automount or amd Commented May 23, 2018 at 16:22
  • @JeffSchaller - it returned "/usr/sbin/automountd". So apparently there is an automounter. Would that explain the mystery? Commented May 23, 2018 at 19:46

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I suspect that the permissions on the root of the NFS filesystem (/acct/c33408) are stricter than the permissions of the stub directory. Before the NFS filesystem is mounted, you're able to inspect the stub directory permissions, but once you trigger the automounter to mount the NFS filesystem, the new permissions do not allow your user to access it.

I tested this locally (with a different directory structure) with similar results:

# stub directory permissions user@host/$ ls -ld /u/testdir drwxr-xr-x 1 root system 1 Jun 2 17:00 /u/testdir # trigger automount as root user@host/$ sudo -s root@host/# cd /u/testdir root@host/u/testdir# exit # NFS permissions user@host/$ ls -ld /u/testdir drwx------ 2 root somegroup 4096 Dec 1 2015 /u/testdir # ls on the NFS mountpoint as a regular user user@host:/$ ls -l /u/testdir ls: /u/testdir: Permission denied total 0 
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  • Alas, the automount occurs automatically, and I lack permissions to bypass it, so (along with the changes of the last three years) there is no way for me to confirm it. But thank you for the answer. Commented Jun 3, 2021 at 3:52

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