ASCII NUL in NAS-Filter-Rule

Guy Fraser guy at incentre.net
Wed Apr 20 17:19:01 CEST 2011


Just a guess, but is sounds like a "string array" to me.

char **string_array ;

Look up malloc and related functions to designate space for additions  
to the array.
This is NOT how you do it but this is the general idea :

$string_array[0] = "filter entry 1" ;
$string_array[1] = "filter entry 2" ;

An "automated" way of "creating" a string array is to use a delimited  
the use index or rindex to find the delimiter then replace the  
delimiter with '\0'.

If you have experienced programing in C, you should know how to find  
all the functions required to carry this out.

On 2011-Apr-20, at 06:38, Ruslan Pustovoytov wrote:

>
> Is my question about sending ascii nul in string attribute is wrong  
> or nobody run into this situation ?
>
>> Hi All
>>
>> My nas box can use attribute NAS-Filter-Rule from radius server to  
>> construct filter rules per subscriber "on the fly".
>> Accodingly to rfc 4849 this attribute should contain ascii NUL  
>> (0x00) as a delimiter between individual filter rules and at the  
>> end of rules.
>> Freeradius define this attribute as a string and I do not know how  
>> to create valid string with nul character.
>> I changed attribute type to octets and successfully add null  
>> character but a whole string converted to hex also and attribute  
>> was not readable.
>> How to send nul character without changing attribute type ?
>> -
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>>
>> .
>>
>
> -
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-- 
Guy Fraser
Network Administrator
The Internet Centre
1-888-450-6787
(780)450-6787




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