Re: BUG: fork do not copy /proc/<PID>/cmdline permissions

From: Agri
Date: Thu Apr 22 2004 - 16:22:35 EST

On Thu, 22 Apr 2004 16:36:28 -0400 (EDT)
"Richard B. Johnson" <root@xxxxxxxxxxxxxxxxxx> wrote:

> On Thu, 22 Apr 2004, Agri wrote:
> > I expected from fork to make a rather complete copy of a process,
> > but it does not copy /proc/<PID>/cmdline access permissions.
> > Therefore, the only way (at least i know) to hide all args of
> > processes is to start every program within shell script:
> > bash -c 'chmod /proc/$$/cmdline; exec userprogramm ...'
> >
> > Tested on 2.6.5.
> >
> > Agri
> Huh? /proc/$PID/cmdline doesn't exist until after a task is
> created.
So setting all /proc/$PID/* file parameters should be a part of task creation.

> What you did was create a task, change whatever
> is in proc, then exec (which doesn't change the PID).
I know that. It solved my problem, but didn't fix the bug.
Any fork of a process reveals all its args.
Everybody have a right to be paranoid to hide everything, don't u think? :-)
Huh... Including number of processes. :-)

> How would you expect fork() to know that you wanted to
> do this? The permissions in /proc are file permissions.
> They have nothing to do with a task.
> Also, any task can read its own command-line without using
> /proc at all.
> Cheers,
> Dick Johnson
> Penguin : Linux version 2.4.26 on an i686 machine (5557.45 BogoMips).
> Note 96.31% of all statistics are fiction.

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at