Thank you Fujimoto-san
/Shivaram
::Sent from my mobile device::
> On Aug 1, 2017, at 9:39 PM, Fujimoto Satoshi <satoshi.fujimo...@gmail.com>
> wrote:
>
> Hi, Shivaram
>
> Oops, I overlooked about it.
>
> It is needed for not only avoiding infinite loop, but also complying RFC.
> For the 'length' field in options, RFC4861 says that:
>
> The value 0 is invalid. Nodes MUST
> silently discard an ND packet that contains an
> option with length zero.
>
> So we should raise an exception when receiving such invalid packets.
> I will make a patch.
>
> Thanks,
> Fujimoto
>
>> On 2017年08月02日 12:13, Shivaram Mysore wrote:
>> Hello,
>>
>> The patch from Bill was suggesting something like this:
>>
>> if cls_ is not None:
>> option = cls_.parser(buf, offset)
>> else:
>> - option = buf[offset:offset + (length * 8 - 2)]
>> + assert length > 0 # avoid infinite loop when length=0
>> + option = buf[offset:offset + (length * 8)]
>> options.append(option)
>> offset += len(option)
>> msg = cls(ch_l, res >> 6, rou_l, rea_t, ret_t, options)
>>
>>
>> Would it be good to check for length too?
>>
>> Thanks
>>
>> /Shivaram
>>
>>> On Tue, Aug 1, 2017 at 7:18 PM, Satoshi Fujimoto
>>> <satoshi.fujimo...@gmail.com> wrote:
>>> The length of nd_option is units of 8 octets.
>>> Currently, for nd_options which is undefined in the ICMPv6 packet library,
>>> the parser assumes that the length is [8 * length - 2].
>>> It causes fails while parsing these options.
>>>
>>> This patch fixes it to parse such options correctly.
>>>
>>> Signed-off-by: Satoshi Fujimoto <satoshi.fujimo...@gmail.com>
>>> ---
>>> ryu/lib/packet/icmpv6.py | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/ryu/lib/packet/icmpv6.py b/ryu/lib/packet/icmpv6.py
>>> index 1e5eaea..7608169 100644
>>> --- a/ryu/lib/packet/icmpv6.py
>>> +++ b/ryu/lib/packet/icmpv6.py
>>> @@ -363,7 +363,7 @@ class nd_router_advert(stringify.StringifyMixin):
>>> if cls_ is not None:
>>> option = cls_.parser(buf, offset)
>>> else:
>>> - option = buf[offset:offset + (length * 8 - 2)]
>>> + option = buf[offset:offset + (length * 8)]
>>> options.append(option)
>>> offset += len(option)
>>> msg = cls(ch_l, res >> 6, rou_l, rea_t, ret_t, options)
>>> --
>>> 2.7.4
>>>
>>>
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>
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