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#!/usr/bin/python
#
from pyasn1.codec.der import decoder, encoder
from pyasn1_modules import rfc2560, rfc2459, pem
from pyasn1.type import univ
import sys, hashlib
try:
import urllib2
except ImportError:
import urllib.request as urllib2
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.readPemBlocksFromFile(
sys.stdin, ('-----BEGIN CERTIFICATE-----', '-----END CERTIFICATE-----')
)[1],
asn1Spec=rfc2459.Certificate()
)
userCert, _ = decoder.decode(
pem.readPemBlocksFromFile(
sys.stdin, ('-----BEGIN CERTIFICATE-----', '-----END CERTIFICATE-----')
)[1],
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))
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