ipfw table add problem

[Michael Butler]

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On 11/25/13 19:18, Mark Andrews wrote:
> 
> In message <1385391778.1220.4.camel at revolution.hippie.lan>, Ian Lepore writes:
>> On Mon, 2013-11-25 at 15:30 +1100, Ian Smith wrote:
>>> On Sun, 24 Nov 2013 23:56:14 +0400, Alexander V. Chernikov wrote:
>>>  > On 24.11.2013 19:43, =D6zkan KIRIK wrote:
>>>  > > Hi,
>>>  > > =
>>
>>>  > > I tested patch. This patch solves, ipfw table 1 add 4899
>>>  > Ok. So I'll commit this fix soon.
>>>  > > =
>>
>>>  > > But, ipfw table 1 add 10.2.3.01 works incorrectly.
>>>  > > output is below.
>>>  > > # ./ipfw table 1 flush
>>>  > > # ./ipfw table 1 add 10.2.3.01
>>>  > inet_pton() does not recognize this as valid IPv4 address, so it is
>>>  > treated as usigned unteger key. It looks like this behavior is mention=
>> ed
>>>  > in STANDARDS section.
>>>  > > # ./ipfw table 1 list
>>>  > > 0.0.0.10/32 0
>>> =
>>
>>> I'm wondering if "so don't do that" is really sufficient to deal with =
>>
>>> this?  If it's not recognised as a valid address, shouldn't it fail to =
>>
>>> add anything, with a complaint?  I don't see how a string containing =
>>
>>> dots can be seen as a valid unsigned integer?
>>
>> It's still not clear to me that inet_pton() is doing the right thing.
>> Per the rfc cited earlier in the thread, it's not supposed to interpret
>> the digits as octal or hex -- they are specifically declared to be
>> decimal numbers.  There's nothing invalid about "01" as a decimal
>> number.  The fact that many of us have a C-programming background and
>> tend to think of leading-zero as implying octal doesn't change that.
> 
> But it does result in unexpected results when there is code that
> does treat 070 as 56 not 70.  Rejecting ambigious input is a good
> thing.  Part of what inet_pton() was trying to do was to get rid
> of the ambiguity in address inputs by tightening up the specification.
> 
> 	10.2.3.70 is not ambigious
> 	10.2.3.070 is ambigious
> 

When the "STANDARDS" section of the inet_pton() man page explicitly
defines the interpretation to be decimal, its rejection of a leading
zero or misinterpretation as octal defies that definition. It does not
say "decimal except when a leading zero is present".

As long as the input string can be be properly interpreted as a decimal
number, it should be.

Misinterpreting "10.2.3.01" as "0.0.0.10/32" without so much as a
warning from either inet_pton() or ipfw is an egregious breach of POLA,

	imb


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