du cannot read directory permission denied

SUSE Linux Enterprise Server SLES for System Z
1

I am executing the du command and I am receiving permission denied on some directories.

linux158:/usr/IBMi/depo/tools/rpm # ls -l total 8 drwxr-xr-x 2 root root 4096 Sep 15 2008 aix drwx------ 2 root root 4096 May 16 2008 src linux158:/usr/IBMi/depo/tools/rpm # du src du: cannot read directory ‘src’: Permission denied 4 src

On another system I created a test with a directory having the same permissions but the su command worked!

root@linux140:/root #~>cd /mnt/ Wed Jun 07 2017 09:16 AM root@linux140:/mnt #~>mkdir test Wed Jun 07 2017 09:16 AM root@linux140:/mnt #~>chmod 700 test Wed Jun 07 2017 09:16 AM root@linux140:/mnt #~>vi test/test Wed Jun 07 2017 09:17 AM root@linux140:/mnt #~>ls -l total 0 drwx------ 2 root root 18 Jun 7 09:17 test Wed Jun 07 2017 09:17 AM root@linux140:/mnt #~>du test 4 test

Are there any suggestions to explain this problem?

2

More information. I found that this directory is part of an auto mount file system. I find that I am allowed access to the /usr/IBMi/depo/tools/rpm/aix directory but not the
/usr/IBMi/depo/tools/rpm/src directory. What would configuration creates this scenario? How would I verify this?

3

I think I may understand what is happening.
The user id. “root” on linux158 is not the user id. of the other system where this is mounted from.

4

Hi Mike,

The user id. “root” on linux158 is not the user id. of the other system where this is mounted from.

yes, indeed - typically, you’ll map the client user “root” to i.e. “nobody” or some other unprivileged user on the NFS server side (“root_squash” option, see “man 5 exports”). This is to protect the file system exported by the server - as the server admin, you cannot guaranteed that the “root” account at the NFS client is safe.

Regards,
J