Initial revision

1 files changed, 136 insertions, 0 deletions

diff --git a/tools/ocspclient.py b/tools/ocspclient.py
new file mode 100644
index 0000000..6680a10
--- /dev/null
+++ b/tools/ocspclient.py
@@ -0,0 +1,136 @@
+from pyasn1.codec.der import decoder, encoder
+from pyasn1_modules import rfc2560, rfc2459, pem
+from pyasn1.type import univ
+import sys, urllib2, hashlib
+
+sha1oid = univ.ObjectIdentifier((1, 3, 14, 3, 2, 26))
+
+class ValueOnlyBitStringEncoder(encoder.encoder.BitStringEncoder):
+    # These methods just do not encode tag and length fields of TLV
+    def encodeTag(self, *args): return ''
+    def encodeLength(self, *args): return ''
+    def encodeValue(*args):
+        substrate, isConstructed = encoder.encoder.BitStringEncoder.encodeValue(*args)
+        # OCSP-specific hack follows: cut off the "unused bit count"
+        # encoded bit-string value.
+        return substrate[1:], isConstructed
+
+    def __call__(self, bitStringValue):
+        return self.encode(None, bitStringValue, defMode=1, maxChunkSize=0)
+
+valueOnlyBitStringEncoder = ValueOnlyBitStringEncoder()
+
+def mkOcspRequest(issuerCert, userCert):
+    issuerTbsCertificate = issuerCert.getComponentByName('tbsCertificate')
+    issuerSubject = issuerTbsCertificate.getComponentByName('subject')
+    
+    userTbsCertificate = userCert.getComponentByName('tbsCertificate')
+    userIssuer = userTbsCertificate.getComponentByName('issuer')
+
+    assert issuerSubject == userIssuer, '%s\n%s' % (
+        issuerSubject.prettyPrint(), userIssuer.prettyPrint()
+        )
+
+    userIssuerHash = hashlib.sha1(
+        encoder.encode(userIssuer)
+        ).digest()
+    
+    issuerSubjectPublicKey = issuerTbsCertificate.getComponentByName('subjectPublicKeyInfo').getComponentByName('subjectPublicKey')
+    
+    issuerKeyHash =  hashlib.sha1(
+        valueOnlyBitStringEncoder(issuerSubjectPublicKey)
+        ).digest()
+    
+    userSerialNumber = userTbsCertificate.getComponentByName('serialNumber')
+
+    # Build request object
+
+    request = rfc2560.Request()
+    
+    reqCert = request.setComponentByName('reqCert').getComponentByName('reqCert')
+    
+    hashAlgorithm = reqCert.setComponentByName('hashAlgorithm').getComponentByName('hashAlgorithm')
+    hashAlgorithm.setComponentByName('algorithm', sha1oid)
+    
+    reqCert.setComponentByName('issuerNameHash', userIssuerHash)
+    reqCert.setComponentByName('issuerKeyHash', issuerKeyHash)
+    reqCert.setComponentByName('serialNumber', userSerialNumber)
+
+    ocspRequest = rfc2560.OCSPRequest()
+    
+    tbsRequest = ocspRequest.setComponentByName('tbsRequest').getComponentByName('tbsRequest')
+    tbsRequest.setComponentByName('version', 'v1')
+    
+    requestList = tbsRequest.setComponentByName('requestList').getComponentByName('requestList')
+    requestList.setComponentByPosition(0, request)
+    
+    return ocspRequest
+
+def parseOcspResponse(ocspResponse):
+    responseStatus = ocspResponse.getComponentByName('responseStatus')
+    assert responseStatus == rfc2560.OCSPResponseStatus('successful'), responseStatus.prettyPrint()    
+    responseBytes = ocspResponse.getComponentByName('responseBytes')
+    responseType = responseBytes.getComponentByName('responseType')
+    assert responseType == id_pkix_ocsp_basic, responseType.prettyPrint()
+    
+    response = responseBytes.getComponentByName('response')
+
+    basicOCSPResponse, _ = decoder.decode(
+        response, asn1Spec=rfc2560.BasicOCSPResponse()
+        )
+    
+    tbsResponseData = basicOCSPResponse.getComponentByName('tbsResponseData')
+
+    response0 = tbsResponseData.getComponentByName('responses').getComponentByPosition(0)
+    
+    return (
+        tbsResponseData.getComponentByName('producedAt'),
+        response0.getComponentByName('certID'),
+        response0.getComponentByName('certStatus').getName(),
+        response0.getComponentByName('thisUpdate')
+        )
+
+if len(sys.argv) != 2:
+    print """Usage:
+$ cat CACertificate.pem userCertificate.pem | %s <ocsp-responder-url>""" % sys.argv[0]
+    sys.exit(-1)
+else:
+    ocspUrl = sys.argv[1]
+
+# Parse CA and user certificates
+
+issuerCert, _ = decoder.decode(
+    pem.readPemFromFile(sys.stdin),
+    asn1Spec=rfc2459.Certificate()
+    )
+userCert, _ = decoder.decode(
+    pem.readPemFromFile(sys.stdin),
+    asn1Spec=rfc2459.Certificate()
+    )
+
+# Build OCSP request
+    
+ocspReq = mkOcspRequest(issuerCert, userCert)
+
+# Use HTTP POST to get response (see Appendix A of RFC 2560)
+# In case you need proxies, set the http_proxy env variable
+
+httpReq = urllib2.Request(
+    ocspUrl,
+    encoder.encode(ocspReq),
+    { 'Content-Type': 'application/ocsp-request' }
+    )
+httpRsp = urllib2.urlopen(httpReq).read()
+
+# Process OCSP response
+    
+ocspRsp, _ = decoder.decode(httpRsp, asn1Spec=rfc2560.OCSPResponse())
+
+producedAt, certId, certStatus, thisUpdate = parseOcspResponse(ocspRsp)
+
+print 'Certificate ID %s is %s at %s till %s\n' % (
+    certId.getComponentByName('serialNumber'),
+    certStatus,
+    producedAt,
+    thisUpdate
+    )