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Date:      Wed, 23 Dec 1998 19:54:54 +1100
From:      Peter Jeremy <peter.jeremy@auss2.alcatel.com.au>
To:        freebsd-security@FreeBSD.ORG
Cc:        dillon@apollo.backplane.com
Subject:   Re: cvs commit: src/etc rc.conf
Message-ID:  <98Dec23.195410est.40360@border.alcanet.com.au>

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Matthew Dillon <dillon@apollo.backplane.com> wrote:
>:The BSD book describes a bug in the mark and sweep garbage collection
>:algorithm than can result in file descriptor hijacking or kernel memory
>:nasties.  Does anyone know if this was ever fixed?  (It is discussed in
>:the 4.4BSD book in a footnote on the page that discusses SCM_RIGHTS)  I
>:glanced through the code for a while this summer while I was modifying the
>:SCM_ ancillary data passing code to be hookable by an LKM.  My goal was to
>:...
>
>    I have no idea.... what does the footnote say exactly?

At the bottom of page 389:
   "If a listening socket is accessible, then any queued connections
    that it holds are also accessible; the garbage collector in 4.4BSD
    fails to take this into account."

This footnote is referenced from a paragraph discussing unp_gc() -
which can be found in kern/uipc_usrreq.c.  From a quick look at the
2.2.6 CVS logs (the latest I can quickly study), it doesn't look like
it's ever been eradicated.

Peter

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