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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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