full-disclosure - THREATCON back up!

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Message-ID: <20020930000417.A6586@hamsec.aurora.sfo.interquest.net>
From: silvio at big.net.au (silvio@....net.au)
Subject: THREATCON back up!

ok.. THREATCON(tm) is back up after resolving the previous segv issuess.

unfortunately - one of our research boxes was denial of serviced when it
ran out of file descriptors.

openbsd/src/sbin/ancontrol/ancontrol.c

has some code that does this

main
	if (s)
		close(s);

	return (0);

well.. here at THREATCON research labs, we use execve wrappers around
this binary, where we do a close(0) to cut down on file descriptor usage,
before exec.  for the above program, we noticed that the above close(s) didn't
actually close the socket because 0 is a valid file descriptor - and
was returned from a socket call, after we did the close(0)  also what
about -1 in the above code?  erm, nevermind.

the recommended patch is to remove the condition competely, since before that
it will exit() if socket() fails (where it checks for s < 0).

also. it is suspected that some code out there does fd checks like this

if (fd <= 0) failure

this is noteably incorrect, because as stated prior, 0 is a valid fd.

I recommend full auditing of all error checking associated with obtaining
a fd!

THREATCON status of "gravelly road", did not change with the release of this
advisory.

--
Silvio