Re: [TLS] Certificate validation can of worms

[[e-mail] (Martin Rex)]

Watson Ladd wrote:
> "Martin Rex" <[e-mail]> wrote:
>>
>>                     PKIX deals with the black box called "certificate
>> path validation" (within which EKU-processing is defined), and with
>> requirements for "conforming CAs" which issue X.509v3 certs (of which
>> there seem to exist very few, if any, considering how much junk
>> X.509v3 certificates are floating around.
>>
>> Could it be that GoDaddy is issuing Server certs that aren't valid
>> ASN.1 DER ?
>>
>> Their ASN.1 DER encoder doesn't seen to implement "BOOLEAN DEFAULT FALSE"
>> correctly:
>>
>> BasicConstraints ::= SEQUENCE {
>>      cA                      BOOLEAN DEFAULT FALSE,
>>      pathLenConstraint       INTEGER (0..MAX) OPTIONAL }
>>
> 
> Well, are they? Short of a hex dump of a GoDaddy certificate+chapter and
> verse of X509 I don't know how we are supposed to evaluate your claim.

openssl asn1dump for Server cert from https://www.verisign.com/

 1087:d=4  hl=2 l=   9 cons: SEQUENCE
 1089:d=5  hl=2 l=   3 prim: OBJECT            :X509v3 Basic Constraints
 1094:d=5  hl=2 l=   2 prim: OCTET STRING      [HEX DUMP]:3000

openssl asn1dump for Server cert from https://www.godaddy.com/

  784:d=4  hl=2 l=  15 cons: SEQUENCE
  786:d=5  hl=2 l=   3 prim: OBJECT            :X509v3 Basic Constraints
  791:d=5  hl=2 l=   1 prim: BOOLEAN           :255
  794:d=5  hl=2 l=   5 prim: OCTET STRING      [HEX DUMP]:3003010100
  801:d=4  hl=2 l=  29 cons: SEQUENCE
  803:d=5  hl=2 l=   3 prim: OBJECT            :X509v3 Extended Key Usage
  808:d=5  hl=2 l=  22 prim: OCTET STRING      [HEX DUMP]:301406082B060105050703
0106082B06010505070302


The godaddy ASN.1 DER encoding problem might be specific to the
BasicConstraints extension.  The criticality Boolean is correctly
omitted in their non-critical ExtendedKeyUsage encoding, but
not within the BasicConstraints extension.


-Martin