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From: Fabrice Bellard <fabrice@bellard.org>
To: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH] Fix scrambling of >32KB packets in slirp
Date: Mon, 01 May 2006 20:05:50 +0200	[thread overview]
Message-ID: <44564DFE.8040400@bellard.org> (raw)
In-Reply-To: <6fe044190605010919q23dcfa19t1d992211c58f679d@mail.gmail.com>

Yes, I would prefer that you resubmit a patch using unsigned types.

Fabrice.

Kenneth Duda wrote:
> Well that is a good question.  When I made this patch, I wanted to
> respect the comment in the code that the author felt that using a
> signed data type was safer in some cases.  However, I will admit that
> I do not understand this reasoning, and I agree that switching to an
> unsigned data type would be better.  Would you like us to resubmit
> this patch in that form?
> 
>    -Ken
> 
> On 5/1/06, Fabrice Bellard <fabrice@bellard.org> wrote:
> 
>> Ed Swierk wrote:
>> > In several places in qemu's slirp code, signed and unsigned ints are
>> > used interchangeably when dealing with IP packet lengths and offsets.
>> > This causes IP packets greater than 32K in length to be scrambled in
>> > various interesting ways that are extremely difficult to troubleshoot.
>> >
>> > Although large IP packets are fairly rare in practice, certain
>> > UDP-based protocols like NFS use them extensively.
>> >
>> > The attached patch wraps IP packet lengths and offsets in macros that
>> > ensure they are always properly treated as unsigned values.
>>
>> Why not changing the definition itself to uint16_t and verifying each
>> occurence of ip_off and ip_len ?
>>
>> Fabrice.
>>
>>
>> _______________________________________________
>> Qemu-devel mailing list
>> Qemu-devel@nongnu.org
>> http://lists.nongnu.org/mailman/listinfo/qemu-devel
>>
> 
> 
> _______________________________________________
> Qemu-devel mailing list
> Qemu-devel@nongnu.org
> http://lists.nongnu.org/mailman/listinfo/qemu-devel
> 
> 

  reply	other threads:[~2006-05-01 19:09 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-05-01  2:55 [Qemu-devel] [PATCH] Fix scrambling of >32KB packets in slirp Ed Swierk
2006-05-01 11:08 ` Fabrice Bellard
2006-05-01 16:19   ` Kenneth Duda
2006-05-01 18:05     ` Fabrice Bellard [this message]
2006-05-02  2:11   ` Ed Swierk

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