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標 題Re: FreeBSD Security Advisory FreeBSD-SA-14:08.tcp
發信站NCTU CS FreeBSD Server (Thu May 1 20:38:29 2014)
轉信站ptt!csnews.cs.nctu!news.cednctu!FreeBSD.cs.nctu!.POSTED!freebsd.org!ow
In message <
[email protected]>, Xin Li <
[email protected]> wrote:
>On 05/01/14 07:19, Karl Pielorz wrote:
>>
>>
>> --On 30 April 2014 04:35:10 +0000 FreeBSD Security Advisories
>> <
[email protected]> wrote:
>>
>>> II. Problem Description
>>>
>>> FreeBSD may add a reassemble queue entry on the stack into the
>>> segment list when the reassembly queue reaches its limit. The
>>> memory from the stack is undefined after the function returns.
>>> Subsequent iterations of the reassembly function will attempt to
>>> access this entry.
>>
>> Hi,
>>
>> Does this require an established TCP session to be present? - i.e.
>> If you have a host which provides no external TCP sessions (i.e.
>> replies 'Connection Refused' / drops the initial SYN) would that
>> still be potentially exploitable?
>
>No. An established TCP session is required.
I also have a question....
If one manages a system where (a) all local user accounts are completely
and 100% trustworthy and where (b) one has in place ipfw rules which reject
all incoming packet *fragments* on all outward-facing interfaces, then is
this security problem (relating to the reassembly queue) an issue at all
for said system? Or is it rather a non-event in such contexts?
Regards,
rfg
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