FreeBSD VM gremlin

From: Charles M. Hannum (rootat_private)
Date: Thu Sep 17 1998 - 07:49:57 PDT

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    I'm sure I'll get lots of flames for forwarding this, but there's been
    a lot of talk about this problem lately, and it definitely has serious
    security implications; even if it turns out to be the case that the
    contents of the file aren't modified, having the time stamp
    pseudo-randomly change would make just about any sysadmin go into a
    fit of paranoia.
    
    
    Message-Id: <199809171409.KAA02717at_private>
    X-Mailer: exmh version 2.0.2 2/24/98
    To: hackersat_private
    Subject: GDB modifies shared libraries?
    Mime-Version: 1.0
    Content-Type: text/plain; charset=us-ascii
    Date: Thu, 17 Sep 1998 10:09:09 -0400
    From: Robert Withrow <bwithrowat_private>
    Sender: owner-freebsd-hackersat_private
    X-Loop: FreeBSD.ORG
    
    I was debugging a (large) program using GDB on an xterm (which
    prevented me from getting the exact text, as you will see).  This
    is on 2.2.6-RELEASE on a P6-200 with 128M ram.  I was running as
    a normal user, not root.
    
    I issued the "run" command and GDB said that /usr/lib/libc.so.3.1
    had changed and it was re-loading it.  That was followed immediately
    by X freezing, and then a spontaneous re-boot.
    
    After the system re-booted, sure enough the date on /usr/lib/libc.so.3.1
    had been changed!
    
    Now, with this program, GDB generally says that the *program* has changed
    *every* time I issue the "run" command, but I thought that was just a
    GDB problem.  But I don't understand how GDB can override protections
    on /usr/lib/libc.so.3.1 in order to change its date.  This seems like
    an OS bug.
    
    Any fixes around?
    
    --
    Robert Withrow -- (+1 978 916 8256)
    BWithrowat_private
    



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