Re: warped security

[jw schultz]

On Sun, Oct 27, 2002 at 03:24:28AM -0500, Albert D. Cahalan wrote:
> 
> As a non-root user:
> 
> a. I can't do readlink() on /proc/1/exe ("ls -l /proc/1/exe")
> b. I can do "cat /proc/1/maps" to see what files are mapped
> 
> That's backwards. If a user can read /proc/1/cmdline, then
> they might as well be permitted to readlink() on /proc/1/exe
> as well. Reading /proc/1/maps is quite another matter,
> exposing more info than the (prohibited) /proc/1/fd/* does.

It seems to have been this way since at least 2.2.  It isn't
exclusive to the /proc/*/exe.  It applies to all symlinks in
/proc/$pid.

As near as i can tell it seems to be a
functional-equivalency carryover from 2.2.  It isn't causing
much harm but i do wonder if this is intentional and if so,
why.  I'm at a loss to see why refusing to allow non-owners
to identify a process's cwd, exe, and root would be
desireable.  The only other things we refuse are mem, fd/
and eviron, the reasons for which are obvious and the
restrictions are per-file rather than as a class.

-- 
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	J.W. Schultz            Pegasystems Technologies
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