/tmp race in Linux kernel source!

From: Peter van Dijk (peterat_private)
Date: Sun Mar 15 1998 - 17:20:37 PST

  • Next message: Peter van Dijk: "bug in su (Slackware 3.4)"

    Ok.. got all your attention there? It's not as bad as it looks ;)
    But there _is_ a /tmp race in /usr/src/linux/scripts/Configure, as used by
    make config (which is, IMHO, obsoleted by make menuconfig):
    
    if [ -f $DEFAULTS ]; then
      echo "#"
      echo "# Using defaults found in" $DEFAULTS
      echo "#"
      . $DEFAULTS
      sed -e 's/# \(.*\) is not.*/\1=n/' < $DEFAULTS > /tmp/conf.$$
      . /tmp/conf.$$
      rm /tmp/conf.$$
    else
    
    File is created and sourced. What more could you wish?
    And to exploit you'll have from start of script to this point to catch it
    and create a fifo in /tmp.
    You know the rest (think GCC symlink exploit): get whatever it puts into
    the fifo and give it back with a little extra, like creating suid shell in
    /tmp.
    
    Greetz, Peter.
    
    ------------------------------------------------------------------------------
     'Selfishness and separation have led me to   .      Peter 'Hardbeat' van Dijk
      to believe that the world is not my problem .    network security consultant
      I am the world. And you are the world.'     .               (yeah, right...)
              Live - 10.000 years (peace is now)  .        peterat_private
    ------------------------------------------------------------------------------
      2:08am  up 1 day, 12:05,  6 users,  load average: 1.10, 1.18, 1.17
    ------------------------------------------------------------------------------
    



    This archive was generated by hypermail 2b30 : Fri Apr 13 2001 - 13:46:21 PDT