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SubjectRe: warped security
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
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.

J.W. Schultz Pegasystems Technologies
email address:
Remember Cernan and Schmitt
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