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Date:      Sat, 8 May 1999 20:26:05 -0700
From:      Don Lewis <Don.Lewis@tsc.tdk.com>
To:        Wes Peters <wes@softweyr.com>, Don Lewis <Don.Lewis@tsc.tdk.com>
Cc:        Kevin Day <toasty@HOME.DRAGONDATA.COM>, security@FreeBSD.ORG
Subject:   Re: KKIS.05051999.003b
Message-ID:  <199905090326.UAA19750@salsa.gv.tsc.tdk.com>
In-Reply-To: Wes Peters <wes@softweyr.com> "Re: KKIS.05051999.003b" (May  7, 11:34pm)

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On May 7, 11:34pm, Wes Peters wrote:
} Subject: Re: KKIS.05051999.003b
} Don Lewis wrote:
} > 
} > On May 6,  2:10pm, Kevin Day wrote:
} > }
} > } Here's my testing so far:
} > }
} > } 2.2.2 - Vulnerable
} > } 2.2.6 - Vulnerable
} > } 2.2.8 - Vulnerable
} > } 3.1-RELEASE - Ran 15 minutes, no crash.
} 
} Let it keep running.  It will (apparently) eventually exhaust all 
} available file handles in an unrecoverable manner.  3.1-R is better, 
} but not invulnerable.

I don't see any obvious descriptor leaks, but the fact that FreeBSD < 3.1
panics (probably in unp_gc(), which Matt fixed) indicates that I'm missing
something.  The exploit code should not result in any calls to unp_gc(),
because the client receives all the descriptors that are sent by the server.
This should result in unp_rights being 0 except when the descriptor is
in flight.  If unp_rights is 0 when the socket is closed, unp_gc() should not
be called.  unp_gc() should only be called if the client closes socket before
receiving the descriptor.

Maybe a third process occasionally get scheduled while the exploit code
has the descriptor in flight and causes unp_gc() to get executed.  If so,
then the exploit shouldn't cause a problem in single user mode.


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