lkml.org 
[lkml]   [1996]   [Apr]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    SubjectRe: ext2 attribute immutable
    Date
    Followup to:  <24376.199604030736@stone.dcs.warwick.ac.uk>
    By author: Zefram <A.Main@dcs.warwick.ac.uk>
    In newsgroup: linux.dev.kernel
    >
    > >> So, how does one need to modify /proc/1/mem to decrease the secure-level
    > >> after getting root access? :)
    > >
    > >You don't need to. You can just do a ptrace() on init, or create your
    > >OWN init process --- by using a careful, controlled fork bomb we can
    > >easily create new processes until we are about to wrap pid, then kill
    > >init and wait until one of our forks has a pid of 1.
    >
    > The fork attack shouldn't be possible. On SunOS, for example, when the
    > PIDs wrap, they wrap to 101, not 1. Doesn't Linux do something like
    > this? If it wraps to 1, this has to change -- conceptually, low PIDs
    > are a privileged resource, so access to them must be restricted.
    >

    Baloney. If init exits, the kernel will automatically spawn a new one
    (Linux); most other OSes will treat init exiting as evidence of a
    fatal crash and panic/reboot. Not only can't you kill init, but you
    can't replace it by any less than changing the binary.

    -hpa

    --
    PGP public key available - finger hpa@zytor.com
    "The earth is but one country, and mankind its citizens." -- Bahá'u'lláh
    I don't work for Yggdrasil, but they sponsor the linux.* hierarchy.


    \
     
     \ /
      Last update: 2005-03-22 13:37    [W:4.264 / U:3.952 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site