Start, End position of PDU in buffer

[reet]

Hi,

I'm currently implementing a decoder for X.509 certificates and thanks to asn1c this process was quite easy and efficient! I was able to extract all the relevant data from a certificate for further processing. So far so good.

But, to verify the signature of a certificate, I need access to the DER encoded TBSCertificate data, which is a sequence member of the Certificate itself:

Certificate  ::=  SEQUENCE  {
     tbsCertificate       TBSCertificate,
     signatureAlgorithm   XAlgorithmIdentifier,
     signature            BIT STRING  }

Is there a way to get the start and end position of a PDU in the 'source' buffer? Or how could I find the sub-buffer designating the DER-encoded TBSCertificate PDU? Is there a helper function for this or can I get this information from the decoded Certificate structure?

Thanks a lot

Kind regards

[Lev Walkin]

You can just der_encode() the tbsCertificate. That'll produce the same data.

[reet]

works great, thanks for your help!