Re: BSD coredumps follow symlinks

[ronny () TMX COM AU (Ronny Cook)]

> 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: ronny () tmx com au ----- Phone: +61-2-9550-4448 ---- Fax: +61-2-9519-2551

All opinions are my own and not those of TMX unless explicitly stated otherwise.