Hexa Value Constraint

[Mourhamo]

Hi guys,

found a new issue, regarding to the size constraint:
In case of a HexaString, the length have to be div by 2
file : constraint.py
function : ValueSizeConstraint
line 106 : l = len(value)/2 to count the number of OCTET

bye

Mourad

[kimgr]

Hello Mourad,

I'm having trouble seeing the bigger picture. What do you suggest asn1ate is doing wrong?

Thanks!

[Mourhamo]

Sorry I did the issue too quickly.

If ASN1 file define a variable with the terms : "fileID OCTET STRING (SIZE(2))"
That means,it has to be an octet string of length 2 Octets

eg: fileID = '0102'

or in the function ValueSizeConstraint (in constraint.py)
in line 106 we count the number of string characters and not octets

to day : line 106 : l = len(value)
I corrected by : line 106 : l = len(value)/2
to count the number of OCTETs and not the string characters

in my case it correct the problem

[kimgr]

constraint.py is part of pyasn1, not asn1ate.

But it could very well be that asn1ate is producing the wrong data for pyasn1, so I don't think you should modify pyasn1.

Can you create a reproducible example and run it by the pyasn1 mailing list (cc me), and maybe we can work out together where the problem is, and how it should be solved?

[Mourhamo]

oh yes I'm quite lost in files :D
Yes for sure i will

[Mourhamo]

Hi Kim,

In fact the probleme is not in pyasn1,

i was thinking that pyasn1 was expecting an hexa like 'FF0D'

but it wait for a b'\xFF\x0D', so the length in string is the double.

in asn1ate, a default Value 'FF0D'H is converted to 'FF0D'H (not a pretty python syntax) when it have to be converted by b'\xFF\x0D' to be pretty regarding to pyasn1

Sorry for the confusing issue :)

Mourad

[kimgr]

I think I understand what the problem is now, but a small, contained example ASN.1 fragment would definitely help.

[Mourhamo]

Here it is:

exctracted from the SimAlliance ASN1

ApplicationInstance ::= SEQUENCE {
applicationLoadPackageAID [APPLICATION 15] ApplicationIdentifier,
classAID [APPLICATION 15] ApplicationIdentifier,
instanceAID [APPLICATION 15] ApplicationIdentifier,
extraditeSecurityDomainAID [APPLICATION 15] ApplicationIdentifier OPTIONAL,
applicationPrivileges [2] OCTET STRING,
lifeCycleState [3] OCTET STRING (SIZE(1)) DEFAULT '07'H,
/* Coding according to GP Life Cycle State. */

applicationSpecificParametersC9 [PRIVATE 9] OCTET STRING,
systemSpecificParameters [PRIVATE 15] ApplicationSystemParameters OPTIONAL,
applicationParameters [PRIVATE 10] UICCApplicationParameters OPTIONAL,
processData SEQUENCE OF OCTET STRING OPTIONAL
}

The line lifeCycleState [3] OCTET STRING (SIZE(1)) DEFAULT '07'H, define a Default value to '07'H
or asn1ate will convert in python as '07'H (not python friendly)
it has to be b'\x07' or binascii.unhexlify('07')
but definitively not '07'H :)

Regards

[kimgr]

Thanks, just what I needed. I'll try and look into this.