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Date: Mon, 28 Dec 2009 15:47:01 +0800
From: Eugene Teo <eugene@...hat.com>
To: oss-security@...ts.openwall.com
CC: "Steven M. Christey" <coley@...us.mitre.org>
Subject: CVE requests - kernel security regressions for CVE-2009-1385/and
 -1389

http://events.ccc.de/congress/2009/Fahrplan//events/3596.en.html

In Fabian's talk, he describes two kernel NIC driver issues:

Issue #1
Fabian claimed that CVE-2009-1385 has an incorrect fix: 
http://git.kernel.org/linus/ea30e11970a96cfe5e32c03a29332554573b4a10.

Which fixes a DoS when the frame spans multiple buffers and the last 
buffer contains less than four bytes. However, if that last fragment is 
longer than 4 bytes, it will actually be taken into account while the 
previous fragments will have been ignored.

Issue #2
The fix for CVE-2009-1389 regarding the r8169 driver introduces a 
similar security problem as this: 
http://git.kernel.org/linus/fdd7b4c3302c93f6833e338903ea77245eb510b4 is 
a revert of this: 
http://git.kernel.org/linus/126fa4b9ca5d9d7cb7d46f779ad3bd3631ca387c.

The accompanying comment for the original commit (126fa):

The size of the incoming frame is not correctly checked.

The RxMaxSize register (0xDA) does not work as expected and incoming 
frames whose size exceeds the MTU actually end spanning multiple 
descriptors. The first Rx descriptor contains the size of the whole 
frame (or some garbage in its place). The driver does not expect 
something above the space allocated to the current skb and crashes 
loudly when it issues a skb_put.

The fix contains two parts:
- disable hardware Rx size filtering: so far it only proved to be able
to trigger some new fancy errors;
[...]

There are other issues he mentioned during his talk, regarding squid and 
pidgin. You can read about it at this wonderful blog: 
http://blog.c22.cc/2009/12/27/26c3-cat-procsysnetipv4fuckups/.

Thanks, Eugene
-- 
Eugene Teo / Red Hat Security Response Team

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