netdev - Re: [Lksctp-developers] SCTP: Fix dead loop while received unexpected chunk with length set to zero

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <46D6C9F2.5020702@hp.com>
Date:	Thu, 30 Aug 2007 09:45:22 -0400
From:	Vlad Yasevich <vladislav.yasevich@...com>
To:	Wei Yongjun <yjwei@...fujitsu.com>
Cc:	lksctp-developers@...ts.sourceforge.net, netdev@...r.kernel.org
Subject: Re: [Lksctp-developers] SCTP: Fix dead loop while received unexpected
 chunk with length set to zero

Wei Yongjun wrote:
> Vlad Yasevich wrote:
>> Wei Yongjun wrote:
>>  
>>> Vlad Yasevich wrote:
>>>    
>>>> NACK
>>>>
>>>> Section 8.4:
>>>>
>>>>    An SCTP packet is called an "out of the blue" (OOTB) packet if it is
>>>>    correctly formed (i.e., passed the receiver's CRC32c check; see
>>>>    Section 6.8), but the receiver is not able to identify the
>>>>    association to which this packet belongs.
>>>>
>>>>
>>>> I would argue that the packet is not correctly formed in this case
>>>> and deserves a protocol violation ABORT in return.
>>>>
>>>> -vlad
>>>>         
>>> As your comment, patch has been changed.
>>> Patch has been split to two, one is resolve this dead loop problem in
>>> this mail.
>>> And the other is come in another mail to discard partial chunk which
>>> chunk length is set to zero.
>>>     
>>
>>
>> I am starting to question the entire OOTB packet handling.  There are way
>> too many function that do almost the same thing and all handle OOTB a
>> little
>> different.
>>
>> sctp_sf_do_9_2_reshutack() is also called during sctp_sf_do_dupcook_a()
>> processing, so checking for INIT chunk is wrong.  Checking for just the
>> chunkhdr_t should be enough.
>>   
> This has been changed.
>> sctp_sf_tabort_8_4_8 is used directly as well (not just through the state
>> machine).  Not sure if the header verification is appropriate.
>>   
> It is needed. Because sctp_sf_tabort_8_4_8() is called to handle OOTB
> packet before check the header length.

But now we are doing the same thing twice (and this is not the only place).
I know I am being really picky here, but I am starting to thing the ootb handling\
is a mess and I really don't want to add to the mess.

Until I (or someone else) prove that it's not a mess or fix it, I am going
to hold off on these patches.

Feel free to go through the spec and fix all the OOTB handling.

Thanks
-vlad

-
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html