Re: [Ethereal-dev] H.225/ASN1 problem

[Cvetan Ivanov <zezo@xxxxxxxxx>]

Hello,

The problem seems to be in the per decoder, probably 
dissect_per_octet_string

in the case
        } else if ((min_len==max_len)&&(min_len<65536)) {  /* 16.7 if 
length is fixed and less than to 64k*/
...
                if (is_per_byte_aligned){
                        BYTE_ALIGN_OFFSET(offset);

val_start is not updated, and if the offset was not aligned from the 
start, val_start points to the previous byte

                if (is_per_byte_aligned){
                        BYTE_ALIGN_OFFSET(offset);
+                       val_start = offset>>3;
                        val_length = min_len;
                        offset+=min_len*8;

seems to fix it, but it would be better if somewone with deeper knolwdge 
about packet-ber takes a look at it

btw it would be nice to replace "per_aligment_type_callback" with 
"per_alignment_type_callback" in the sources


Cvetan Ivanov wrote:
> Hello,
>
> While trying few captures with the current svn, I noticed that ip 
> addresses and GUIDs are decoded incorrectly.
>
> example:
>
> we have source signall address element that looks like this:
>
> 00 01 02 03 04 05 06
>
> where 0 means ipAddress and the IP should be 1.2.3.4 port 0x0506
> but it's decoded instead as 0.1.2.3 port 0x0506
>
> the same thing goes for the CallIdentifier -
>
> 00 01 02 .... (17 bytes) is decoded like guid 000102..., and it should 
> be 010203...
>
> Tested on two different linux systems. Unfortunatrly I'm not too much 
> into asn1 and don't have idea how to debug this further.


best regards,

Cvetan


--
Cvetan Ivanov
System Administrator
SpectrumNet Jsc.
+35929657613 Office