Re: Fw: Local Denial-of-Service attack against Linux

From: David S. Miller (davem@redhat.com)
Date: Sun Mar 26 2000 - 07:44:35 EST


   Date: Sun, 26 Mar 2000 13:36:50 +0200
   From: Manfred Spraul <manfreds@colorfullife.com>

   I overlooked that when I updated the message queue code: you could
   kill the computer by sending lots of 0-byte messages to a SysV
   message queue :-/

Also, as another example, send the following packet sequence to a BSD
tcp stack:

        last byte in window
        last 2 bytes in window
        last 3 bytes in window
        last 4 bytes in window

For a long time (I don't know if it is fixed now) you could use this
to make the kernel allocate "rcvbuf factorial" bytes of space per
socket on a BSD machine. (It's not a very useful remote DoS because
you have to create a real connection and thus give away your identity
to perform the attack)

I know at least FreeBSD fixed the Unix fd passing leak, so they
probably fixed this particular TCP nasty as well.

Later,
David S. Miller
davem@redhat.com

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