Re: BSD coredumps follow symlinks

From: Ronny Cook (ronnyat_private)
Date: Sun Apr 05 1998 - 18:16:04 PDT

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    > lpr will dump core if there is no symlink there. Maybe you failed to
    > install the patch correctly?
    
    If I recall rightly, the first patch disabled the most obvious attacks, but
    allowed a core dump for a setuid program across a symbolic link *if* the file
    existed and had 600 permissions (and was owned by the appropriate user).
    
    Unfortunately, certain sensitive files (such as /etc/master.passwd) fit
    these conditions. Thus the later patch under 3.0, which disabled *any*
    core dump across a symbolic link for *any* setuid program.
    
    Nir's test was only for a nonexistent file, which the earlier patch handles
    correctly. Unfortunately, in doing so it opens the other security hole
    which was later patched under 3.0.
    
                    ...Ronny
    --
     Ronald Cook, Technical Manager - Message Handling Systems/The Message eXchange
     Email: ronnyat_private ----- Phone: +61-2-9550-4448 ---- Fax: +61-2-9519-2551
    
    All opinions are my own and not those of TMX unless explicitly stated otherwise.
    



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