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Re: a secure base system
From: martin f krafft <madduck () madduck net>
Date: Mon, 15 Mar 2004 22:16:41 +0100

also sprach Valdis.Kletnieks () vt edu <Valdis.Kletnieks () vt edu> [2004.03.15.2108 +0100]:
On typical Linux distributions noexec is pointless.
It does not prevent the execution of dynamically linked ELF images.

$ readelf -l /bin/bash | grep interpreter
      [Requesting program interpreter: /lib/ld-linux.so.2]

$ /lib/ld-linux.so.2 /bin/bash --version
GNU bash, version 2.05b.0(1)-release (i386-redhat-linux-gnu)
Copyright (C) 2002 Free Software Foundation, Inc.

This is fixed in the 2.6 kernel.

Wow, I didn't know this. Thanks for letting us know!

piper:~> uname -a
Linux piper 2.6.4-piper #1 Sun Mar 14 18:37:46 CET 2004 i686 GNU/Linux

piper:~> cp /bin/bash /tmp

piper:~> /lib/ld-linux.so.2 /tmp/bash --version
/tmp/bash: error while loading shared libraries: /tmp/bash: failed
to map segment from shared object: Operation not permitted

-- 
martin;              (greetings from the heart of the sun.)
  \____ echo mailto: !#^."<*>"|tr "<*> mailto:"; net () madduck
 
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bill gates, 1984: "640 k ought to be enough"
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bill gates, 1999: "linux has no impact on microsoft's strategy"

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