Subject: Mountpoint permission bits
To: None <current-users@NetBSD.ORG>
From: Paul Ripke <>
List: current-users
Date: 05/31/2000 13:21:02

I've tripped over this at work, and brief investigation has shown
that the following "feature" occurs with NetBSD, AIX and Solaris,
while DEC UNIX (Tru 64, whatever), SCO and Linux are unaffected.
I don't have access to any other breeds to test; I don't see it as
a problem, I was just after a brief explanation from someone in
the know - I also find it interesting as to which side of the
fence various Unices fall - representative of code base? Hmm...

Script started on Wed May 31 22:34:17 2000
bash-2.02# umount /proc
bash-2.02# chmod 111 /proc
bash-2.02# mount /proc
bash-2.02# su - stix
stix:bash$ ls -ld /proc/..
drwxr-xr-x  17 root  wheel  512 Jan 10 06:07 /proc/..
stix:bash$ exit
bash-2.02# umount /proc
bash-2.02# chmod 000 /proc
bash-2.02# mount /proc
bash-2.02# su - stix
stix:bash$ ls -ld /proc/..
ls: /proc/..: Permission denied
stix:bash$ exit
bash-2.02# exit

Script done on Wed May 31 22:35:37 2000

Paul Ripke
UNIX/OpenVMS System Administrator, Data Management
BHP Information Technology
Phone: +61 2 4275 4101, Fax: +61 2 4275 7801
Computer Centre, Five Islands Rd, Port Kembla, NSW 2505, AUSTRALIA