all: Keep track of certificate issuances.

And use this tracking to to warn about surviving certificates which are
related to the one just revoked - they may need some attention too.

NOTE: While this should be correctly implemented, I think this is not
usable, and hence probably not worth the extra complexity: what can one
do when given a list of serials ? This version discards old tracking
entries, but even if it did not how is one supposed to browse these ?

caucase/ca.py

@@ -38,7 +38,9 @@ from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
 from . import utils
 from .exceptions import (
   CertificateVerificationError,
+  CertificateRevokedError,
   NotACertificateSigningRequest,
+  Found,
 )
 
 __all__ = ('CertificateAuthority', 'UserCertificateAuthority', 'Extension')
@@ -245,7 +247,12 @@ class CertificateAuthority(object):
     if requested_amount is not None and \
     requested_amount <= self._auto_sign_csr_amount:
       # if allowed to sign this certificate automaticaly
-      self._createCertificate(csr_id, auto_signed=_AUTO_SIGNED_YES)
+      self._createCertificate(
+        csr_id,
+        auto_signed=_AUTO_SIGNED_YES,
+        is_renewal=False,
+        authorisation_serial=None,
+      )
     return csr_id
 
   def deletePendingCertificateSigningRequest(self, csr_id):
@@ -264,7 +271,7 @@ class CertificateAuthority(object):
     """
     return self._storage.getCertificateSigningRequestList()
 
-  def createCertificate(self, csr_id, template_csr=None):
+  def createCertificate(self, csr_id, template_csr=None, authorisation_serial=None):
     """
     Sign a pending certificate signing request, storing produced certificate.
 
@@ -274,39 +281,97 @@ class CertificateAuthority(object):
       Copy extensions and subject from this CSR instead of stored one.
       Useful to renew a certificate.
       Public key is always copied from stored CSR.
+    authorisation_serial (int, None)
+      Serial of the certificate which authorised certificate issuance.
     """
     self._createCertificate(
       csr_id=csr_id,
       auto_signed=_AUTO_SIGNED_NO,
       template_csr=template_csr,
+      is_renewal=False,
+      authorisation_serial=authorisation_serial,
     )
 
-  def _createCertificate(self, csr_id, auto_signed, template_csr=None):
+  def _createCertificate(
+    self,
+    csr_id,
+    auto_signed,
+    is_renewal,
+    authorisation_serial,
+    template_csr=None,
+  ):
     """
     auto_signed (bool)
       When True, mark certificate as having been auto-signed.
       When False, prevent such mark from being set.
       When None, do not filter (useful when renewing).
+    is_renewal (bool)
+      True to signal a renewal, False otherwise.
+    authorisation_serial (int, None)
+      If non-None, the serial of the certificate which authorised certificate
+      issuance:
+      - If is_renewal is True, this is the serial of the certificate being
+        renewed.
+      - Otherwise, this is the serial of user certificate who triggered the
+        renewal.
+      If None, this is an auto-issued certificate.
     tempate_csr (None or X509Req)
       Copy extensions and subject from this CSR instead of stored one.
       Useful to renew a certificate.
       Public key is always copied from stored CSR.
     """
-    csr_pem = self._storage.getCertificateSigningRequest(csr_id)
-    csr = utils.load_certificate_request(csr_pem)
+    not_valid_before = datetime.datetime.utcnow()
+    not_valid_after = not_valid_before + self._crt_life_time
+    csr = utils.load_certificate_request(
+      self._storage.getCertificateSigningRequest(csr_id),
+    )
+    # Note: this is quite unlikely to loop even once, as
+    # x509.random_serial_number produces a 160-bits random number.
+    while True:
+      serial_number = x509.random_serial_number()
+      try:
+        with self._storage.trackIssuance(
+          is_renewal=is_renewal,
+          authorisation_serial=authorisation_serial,
+          serial=serial_number,
+          not_valid_after=utils.datetime2timestamp(not_valid_after),
+        ) as storeCertificate:
+          return self.__createCertificate(
+            csr_id=csr_id,
+            csr=csr,
+            auto_signed=auto_signed,
+            template_csr=template_csr,
+            serial_number=serial_number,
+            not_valid_before=not_valid_before,
+            not_valid_after=not_valid_after,
+            storeCertificate=storeCertificate,
+          )
+      except Found: # pragma: no cover
+        pass
+
+  def __createCertificate(
+    self,
+    csr_id,
+    csr,
+    auto_signed,
+    template_csr,
+    serial_number,
+    not_valid_before,
+    not_valid_after,
+    storeCertificate,
+  ):
     if template_csr is None:
       template_csr = csr
     ca_key_pair = self._getCurrentCAKeypair()
     ca_crt = ca_key_pair['crt']
 
     public_key = csr.public_key()
-    now = datetime.datetime.utcnow()
     builder = x509.CertificateBuilder(
       subject_name=template_csr.subject,
       issuer_name=ca_crt.subject,
-      not_valid_before=now,
-      not_valid_after=now + self._crt_life_time,
-      serial_number=x509.random_serial_number(),
+      not_valid_before=not_valid_before,
+      not_valid_after=not_valid_after,
+      serial_number=serial_number,
       public_key=public_key,
       extensions=[
         Extension(
@@ -459,7 +524,7 @@ class CertificateAuthority(object):
       algorithm=self._default_digest_class(),
       backend=_cryptography_backend,
     ))
-    self._storage.storeCertificate(csr_id, cert_pem)
+    storeCertificate(csr_id, cert_pem)
     return cert_pem
 
   def getCertificate(self, csr_id):
@@ -662,6 +727,7 @@ class CertificateAuthority(object):
     crt_pem (str)
       PEM-encoded certificat to revoke.
     """
+    try:
       crt = utils.load_certificate(
         crt_pem,
         self.getCACertificateList(),
@@ -670,6 +736,8 @@ class CertificateAuthority(object):
           _cryptography_backend,
         ),
       )
+    except CertificateRevokedError:
+      raise Found
     self._storage.revoke(
       serial=crt.serial_number,
       expiration_date=utils.datetime2timestamp(crt.not_valid_after),
@@ -695,6 +763,18 @@ class CertificateAuthority(object):
       )),
     )
 
+  def getIssuedBy(self, serial_list, renewal):
+    """
+    (see .storage.getIssuedBy)
+    """
+    return self._storage.getIssuedBy(serial_list, renewal)
+
+  def getNonRevokedCertificateSerialList(self, serial_list):
+    """
+    (see .storage.getNonRevokedCertificateSerialList)
+    """
+    return self._storage.getNonRevokedCertificateSerialList(serial_list)
+
   def renew(self, crt_pem, csr_pem):
     """
     Renew certificate.
@@ -718,6 +798,8 @@ class CertificateAuthority(object):
         override_limits=True,
       ),
       auto_signed=_AUTO_SIGNED_PASSTHROUGH,
+      is_renewal=True,
+      authorisation_serial=crt.serial_number,
       # Do a dummy signature, just so we get a usable
       # x509.CertificateSigningRequest instance. Use latest CA private key just
       # because it is available for free (unlike generating a new one).

caucase/cli.py

@@ -193,6 +193,18 @@ class CLICaucaseClient(object):
           crt_file.write(crt_pem)
     return warning, error
 
+  def _printRevocationResult(self, result):
+    if result:
+      self._print(
+        'WARNING: The certificate just revoked has been used to issue '
+        'certificates with the following serials:',
+      )
+      for mode, serial_list in result.iteritems():
+        self._print('mode:', mode)
+        for serial in serial_list:
+          self._print(' ', serial)
+      self._print('You may want to check these.')
+
   def revokeCRT(self, error, crt_key_list):
     """
     --revoke-crt
@@ -209,7 +221,14 @@ class CLICaucaseClient(object):
         )
         error = True
         continue
-      self._client.revokeCertificate(crt, key)
+      try:
+        result = self._client.revokeCertificate(crt, key)
+      except CaucaseError as e:
+        if e.args[0] != httplib.CONFLICT:
+          raise
+        self._print('Certificate', crt_path, 'was already revoked')
+        result = e.args[2]
+      self._printRevocationResult(result)
     return error
 
   def renewCRT(
@@ -343,14 +362,29 @@ class CLICaucaseClient(object):
           ),
           file=self._stderr,
         )
-      self._client.revokeCertificate(crt_pem)
+      try:
+        result = self._client.revokeCertificate(crt_pem)
+      except CaucaseError as e:
+        if e.args[0] != httplib.CONFLICT:
+          raise
+        self._print('Certificate', crt_path, 'was already revoked')
+        result = e.args[2]
+      self._printRevocationResult(result)
+    return error
 
   def revokeSerial(self, serial_list):
     """
     --revoke-serial
     """
     for serial in serial_list:
-      self._client.revokeSerial(serial)
+      try:
+        result = self._client.revokeSerial(serial)
+      except CaucaseError as e:
+        if e.args[0] != httplib.CONFLICT:
+          raise
+        self._print('Certificate', serial, 'was already revoked')
+        result = e.args[2]
+      self._printRevocationResult(result)
 
 def main(argv=None, stdout=sys.stdout, stderr=sys.stderr):
   """

caucase/client.py

@@ -330,12 +330,19 @@ class CaucaseClient(object):
       data = utils.nullWrap({
         'revoke_crt_pem': crt,
       })
-    method(
+    try:
+      return json.loads(method(
         'PUT',
         '/crt/revoke',
         json.dumps(data).encode('utf-8'),
         {'Content-Type': 'application/json'},
-    )
+      ).decode('utf-8'))
+    except CaucaseError as e:
+      if e.args[0] != httplib.CONFLICT: # pragma: no cover
+        raise
+      args = list(e.args)
+      args[2] = json.loads(e.args[2].decode('utf-8'))
+      raise CaucaseError(*args)
 
   def revokeSerial(self, serial):
     """
@@ -345,12 +352,19 @@ class CaucaseClient(object):
 
     [AUTHENTICATED]
     """
-    self._https(
+    try:
+      return json.loads(self._https(
         'PUT',
         '/crt/revoke',
         json.dumps(utils.nullWrap({'revoke_serial': serial})).encode('utf-8'),
         {'Content-Type': 'application/json'},
-    )
+      ).decode('utf-8'))
+    except CaucaseError as e:
+      if e.args[0] != httplib.CONFLICT: # pragma: no cover
+        raise
+      args = list(e.args)
+      args[2] = json.loads(e.args[2].decode('utf-8'))
+      raise CaucaseError(*args)
 
   def createCertificate(self, csr_id, template_csr=''):
     """

caucase/exceptions.py

@@ -42,6 +42,10 @@ class CertificateVerificationError(CertificateAuthorityException):
   """Certificate is not valid, it was not signed by CA"""
   pass
 
+class CertificateRevokedError(CertificateVerificationError):
+  """Certificate is revoked"""
+  pass
+
 class NotACertificateSigningRequest(CertificateAuthorityException):
   """Provided value is not a certificate signing request"""
   pass

caucase/storage.py

@@ -22,6 +22,7 @@
 Caucase - Certificate Authority for Users, Certificate Authority for SErvices
 """
 from __future__ import absolute_import
+import contextlib
 from random import getrandbits
 import os
 import sqlite3
@@ -53,7 +54,7 @@ class NoReentryConnection(sqlite3.Connection):
     self.__entered = False
     return super(NoReentryConnection, self).__exit__(exc_type, exc_value, traceback)
 
-class SQLite3Storage(local):
+class SQLite3Storage(local): # pylint: disable=too-many-public-methods
   """
   CA data storage.
 
@@ -106,10 +107,10 @@ class SQLite3Storage(local):
     self._table_prefix = table_prefix
     db.row_factory = sqlite3.Row
     self._max_csr_amount = max_csr_amount
-    self._crt_keep_time = crt_keep_time * DAY_IN_SECONDS
+    self._crt_keep_time = int(crt_keep_time * DAY_IN_SECONDS)
     self._crt_read_keep_time = crt_read_keep_time * DAY_IN_SECONDS
     with db:
-      # Note about revoked.serial: certificate serials exceed the 63 bits
+      # Note about serials: certificate serials exceed the 63 bits
       # sqlite can accept as integers, so store these as text. Use a trivial
       # string serialisation: not very space efficient, but this should not be
       # a limiting issue for our use-cases anyway.
@@ -142,7 +143,13 @@ class SQLite3Storage(local):
         CREATE TABLE IF NOT EXISTS %(prefix)sconfig_once (
           name TEXT PRIMARY KEY,
           value TEXT
-        )
+        );
+        CREATE TABLE IF NOT EXISTS %(prefix)sissuance (
+          serial TEXT PRIMARY KEY,
+          is_renewal INTEGER,
+          authorisation_serial TEXT,
+          not_valid_after INTEGER
+        );
       ''' % {
         'prefix': table_prefix,
         'key_id_constraint': 'UNIQUE' if enforce_unique_key_id else '',
@@ -374,29 +381,6 @@ class SQLite3Storage(local):
         ).fetchall()
       ]
 
-  def storeCertificate(self, csr_id, crt):
-    """
-    Store certificate for pre-existing CSR.
-
-    Raises NotFound if there is no matching CSR, or if a certificate was
-    already stored.
-    """
-    with self._db as db:
-      c = db.cursor()
-      c.execute(
-        'UPDATE %scrt SET crt=?, expiration_date = ? '
-        'WHERE id = ? AND crt IS NULL' % (
-          self._table_prefix,
-        ),
-        (
-          crt,
-          int(time() + self._crt_keep_time),
-          csr_id,
-        ),
-      )
-      if c.rowcount == 0:
-        raise NotFound
-
   def getCertificate(self, crt_id):
     """
     Retrieve a PEM-encoded certificate.
@@ -463,6 +447,82 @@ class SQLite3Storage(local):
           break
         yield toBytes(row['crt'])
 
+  @contextlib.contextmanager
+  def trackIssuance(self, is_renewal, authorisation_serial, serial, not_valid_after):
+    """
+    Track certificate issuance.
+
+    is_renewal (bool)
+      If true, this is a renewal.
+      Otherwise, it is an original issuance.
+    authorisation_serial (int)
+      Serial of the certificate which authorised issuance:
+      - renewed certificate serial if is_renewal is true
+      - user certificate serial otherwise
+      - None if certificate was auto-signed
+    serial (int)
+      Serial of issued certificate.
+    not_valid_after (int)
+      Expiration timestamp of issued certificate.
+
+    Returns a context manager which, on entry raises Found if serial has
+    already been issued. Otherwise, returns a callable taking 2 parameters
+    storing certificate for a pre-existing CSR:
+    csr_id (int)
+      CSR identifier.
+    crt (str)
+      PEM-encoded certificate.
+    Raises NotFound if there is no matching CSR, or if a certificate was
+    already stored.
+    """
+    with self._db as db:
+      now = int(time())
+      c = db.cursor()
+      c.execute(
+        'DELETE FROM %sissuance '
+        'WHERE not_valid_after < ?' % (
+          self._table_prefix,
+        ),
+        (
+          now,
+        ),
+      )
+      try:
+        c.execute(
+          'INSERT INTO %sissuance '
+          '  (is_renewal, authorisation_serial, serial, not_valid_after) '
+          'VALUES (?, ?, ?, ?)' % (
+            self._table_prefix,
+          ),
+          (
+            int(is_renewal),
+            str(authorisation_serial),
+            str(serial),
+            not_valid_after,
+          ),
+        )
+      except sqlite3.IntegrityError: # pragma: no cover
+        raise Found
+      # Just to have a mutable
+      store_argument_list = []
+      yield lambda csr_id, crt: store_argument_list.append((csr_id, crt))
+      # pylint: disable=unbalanced-tuple-unpacking
+      (csr_id, crt), = store_argument_list
+      # pylint: enable=unbalanced-tuple-unpacking
+      c.execute(
+        'UPDATE %scrt SET crt=?, expiration_date = ? '
+        'WHERE id = ? AND crt IS NULL' % (
+          self._table_prefix,
+        ),
+        (
+          crt,
+          now + self._crt_keep_time,
+          csr_id,
+        ),
+      )
+      if c.rowcount == 0:
+        raise NotFound
+
   def revoke(self, serial, expiration_date):
     """
     Add given certificate serial to the list of revoked certificates.
@@ -495,6 +555,74 @@ class SQLite3Storage(local):
       except sqlite3.IntegrityError:
         raise Found
 
+  def getIssuedBy(self, serial_list, renewal):
+    """
+    Returns the list of serials of certificates which were issued, directly or
+    not, using the certificates with given serials.
+
+    serial_list (list of int)
+      Serial of the certificates to query the descendants of.
+    renewal (bool)
+      If true, only renewals will be followed.
+      Otherwise, initial issuances by given serials are fetched, and then
+      the renewals of these are followed. Renewals of given serials are not
+      followed.
+    """
+    # do not mutate parameter
+    serial_list = list(serial_list)
+    result = set()
+    with self._db as db:
+      c = db.cursor()
+      while serial_list:
+        for next_serial, in c.execute(
+          'SELECT serial FROM %sissuance '
+          'WHERE authorisation_serial = ?%s' % (
+            self._table_prefix,
+            ' and is_renewal = 1' if renewal else '',
+          ),
+          (
+            str(serial_list.pop()),
+          ),
+        ):
+          next_serial = int(next_serial)
+          # Unlikely to be false: serials are server-enforced and random
+          # enough to be very unlikely to be reused. But still prevents a
+          # possible infinite loop.
+          if next_serial not in result:
+            serial_list.append(next_serial)
+            result.add(next_serial)
+          else: # pragma: no cover
+            pass
+      return list(result)
+
+  def getNonRevokedCertificateSerialList(self, serial_list):
+    """
+    Return the list of serials whose certificates are not revoked, out of
+    those provided.
+
+    serial_list (list of int)
+      List of certificate serials to check for non-revocation.
+    """
+    if serial_list:
+      with self._db as db:
+        revoked_serial_set = {
+          int(x)
+          for x, in db.cursor().execute(
+            'SELECT serial FROM %srevoked WHERE serial IN (%s)' % (
+              self._table_prefix,
+              ','.join('?' * len(serial_list)),
+            ),
+            [str(x) for x in serial_list],
+          )
+        }
+    else:
+      revoked_serial_set = ()
+    return [
+      x
+      for x in serial_list
+      if x not in revoked_serial_set
+    ]
+
   def getCertificateRevocationList(self):
     """
     Get PEM-encoded current Certificate Revocation List.

caucase/test.py

@@ -24,8 +24,9 @@ Caucase - Certificate Authority for Users, Certificate Authority for SErvices
 Test suite
 """
 # pylint: disable=too-many-lines, too-many-public-methods
-from __future__ import absolute_import
+from __future__ import absolute_import, print_function
 from Cookie import SimpleCookie
+from collections import defaultdict
 import datetime
 # pylint: disable=no-name-in-module, import-error
 from distutils.spawn import find_executable
@@ -331,7 +332,7 @@ class CaucaseTest(unittest.TestCase):
     Prepare test data directory and file paths, and start caucased as most
     tests will need to interact with it.
     """
-    global _clean_caucased_snapshot
+    global _clean_caucased_snapshot # pylint: disable=global-statement
     self._data_dir = data_dir = tempfile.mkdtemp(prefix='caucase_test_')
 
     self._client_dir = client_dir = os.path.join(data_dir, 'client')
@@ -1067,23 +1068,17 @@ class CaucaseTest(unittest.TestCase):
     # and crt & key did not change
     self.assertEqual(service2_crt_after, service2_crt_after2)
     self.assertEqual(service2_key_after, service2_key_after2)
-    # revoking again one's own certificate fails
-    self.assertRaises(
-      CaucaseError,
-      self._runClient,
+    # revoking again one's own certificate does not fail
+    self._runClient(
       '--revoke-crt', service2_key_path, '',
     )
     # as does revoking with an authenticated user
-    self.assertRaises(
-      CaucaseError,
-      self._runClient,
+    self._runClient(
       '--user-key', user_key_path,
       '--revoke-other-crt', service2_key_path,
     )
     # and revoking by serial
-    self.assertRaises(
-      CaucaseError,
-      self._runClient,
+    self._runClient(
       '--user-key', user_key_path,
       '--revoke-serial', str(
         utils.load_certificate(
@@ -2290,6 +2285,16 @@ class CaucaseTest(unittest.TestCase):
       user_key_path,
       'user',
     )
+    user2_key_renewal_query_fragment = (
+      ",1,'%i'" % utils.load_certificate(
+        utils.getCert(user2_key_path),
+        [
+          utils.load_ca_certificate(x)
+          for x in utils.getCertList(self._client_user_ca_crt)
+        ],
+        None,
+      ).serial_number
+    ).encode('utf-8')
     # user2 sacrifice their private key, and prepare its replacement
     basename = self._getBaseName()
     user2_new_key_path = self._createPrivateKey(basename)
@@ -2377,12 +2382,14 @@ class CaucaseTest(unittest.TestCase):
     CRL_INSERT = b'INSERT INTO "caucrl" '
     CRT_INSERT = b'INSERT INTO "caucrt" '
     REV_INSERT = b'INSERT INTO "caurevoked" '
+    ISSUED_INSERT = b'INSERT INTO "cauissuance" '
     def filterBackup(backup, expect_rev):
       """
       Remove all lines which are know to differ between original batabase and
       post-restoration database, so the rest (which must be the majority of the
       database) can be tested to be equal.
       """
+      renew_found = None
       rev_found = not expect_rev
       new_backup = []
       crt_list = []
@@ -2395,6 +2402,13 @@ class CaucaseTest(unittest.TestCase):
         if row.startswith(REV_INSERT): # pragma: no cover
           assert not rev_found, 'Unexpected revocation found'
           continue
+        if (
+          row.startswith(ISSUED_INSERT) and
+          user2_key_renewal_query_fragment in row
+        ):
+          assert renew_found is None, '\n%r\n%r' % (renew_found, row)
+          renew_found = row
+          continue
         new_backup.append(row)
       return new_backup, crt_list
 
@@ -3127,6 +3141,220 @@ class CaucaseTest(unittest.TestCase):
     )
     self.assertFalse(user_certificate_policies.critical)
 
+  def testIssuanceTracking(self):
+    """
+    Issue a few certificates, revoke a few and check that all their
+    descendents are listed.
+    """
+    self._runClient()
+    cas_crt_list = [
+      utils.load_ca_certificate(x)
+      for x in utils.getCertList(self._client_ca_crt)
+    ]
+    self._runClient('--mode', 'user')
+    cau_crt_list = [
+      utils.load_ca_certificate(x)
+      for x in utils.getCertList(self._client_user_ca_crt)
+    ]
+    def getSerial(key_path, ca_crt_list):
+      'get serial as a string'
+      return str(utils.load_certificate(
+        utils.getCert(key_path),
+        ca_crt_list,
+        None,
+      ).serial_number)
+    def approveUser(user_key_path):
+      'issue a new user certificate'
+      new_key_path = self._createAndApproveCertificate(
+        user_key_path,
+        'user',
+      )
+      return new_key_path, getSerial(new_key_path, cau_crt_list)
+    def approveService(user_key_path):
+      'issue a new service certificate'
+      new_key_path = self._createAndApproveCertificate(
+        user_key_path,
+        'service',
+      )
+      return new_key_path, getSerial(new_key_path, cas_crt_list)
+    def renew(mode, key_path):
+      'renew a <mode> certificate'
+      self._runClient(
+        '--mode', mode,
+        '--threshold', '100',
+        '--renew-crt', key_path, '',
+      )
+    def renewUser(key_path):
+      'renew a user certificate'
+      renew('user', key_path)
+      return getSerial(key_path, cau_crt_list)
+    def renewService(key_path):
+      'renew a service certificate'
+      renew('service', key_path)
+      return getSerial(key_path, cas_crt_list)
+    def assertRevokeResult(expected_dict, args, already_revoked=False):
+      'revoke a certificate and check displayed descendant certificates'
+      mode = None
+      output_dict = defaultdict(list)
+      output = self._runClient(*args)
+      already_revoked_found = False
+      for line in output.splitlines():
+        if line.endswith('was already revoked'):
+          already_revoked_found = True
+        elif line.startswith('mode: '):
+          _, mode = line.split()
+        elif mode is not None and line.startswith('  '):
+          output_dict[mode].append(line.strip())
+      self.assertEqual(already_revoked, already_revoked_found)
+      self.assertItemsEqual(expected_dict.keys(), output_dict.keys())
+      for mode, expected_value_list in expected_dict.iteritems():
+        self.assertItemsEqual(expected_value_list, output_dict[mode])
+    # Get first user certificate
+    user0_key_path = self._createFirstUser()
+    user0_serial0 = getSerial(user0_key_path, cau_crt_list)
+    # renew user0 certificate
+    user0_serial1 = renewUser(user0_key_path)
+    # Sanity check renewal
+    self.assertNotEqual(user0_serial0, user0_serial1)
+    # Get two more user certificates approved by user0
+    user1_key_path, user1_serial = approveUser(user0_key_path)
+    user2_key_path, user2_serial0 = approveUser(user0_key_path)
+    # renew user2 certificate
+    user2_serial1 = renewUser(user2_key_path)
+    # Get a service certificate approved by each user
+    service0_key_path, service0_serial0 = approveService(user0_key_path)
+    service1_key_path, service1_serial0 = approveService(user1_key_path)
+    service2_key_path, service2_serial0 = approveService(user2_key_path)
+    # Renew each
+    service0_serial1 = renewService(service0_key_path)
+    service1_serial1 = renewService(service1_key_path)
+    service2_serial1 = renewService(service2_key_path)
+    # because serials are unreadable, print a mapping to display if test fails
+    test_output = utils.toUnicodeWritableStream(self.caucase_test_output)
+    for serial, name in (
+      (user0_serial0, 'user0_serial0'),
+      (user0_serial1, 'user0_serial1'),
+      (user1_serial, 'user1_serial'),
+      (user2_serial0, 'user2_serial0'),
+      (user2_serial1, 'user2_serial1'),
+      (service0_serial0, 'service0_serial0'),
+      (service1_serial0, 'service1_serial0'),
+      (service2_serial0, 'service2_serial0'),
+      (service0_serial1, 'service0_serial1'),
+      (service1_serial1, 'service1_serial1'),
+      (service2_serial1, 'service2_serial1'),
+    ):
+      print(serial, 'is', name, file=test_output)
+
+    assertRevokeResult(
+      { # One renewal, which issued one service, which was renewed
+        'user': [user2_serial1],
+        'service': [service2_serial0, service2_serial1],
+      }, (
+        '--mode', 'user',
+        '--user-key', user0_key_path,
+        '--revoke-serial', user2_serial0,
+      ),
+    )
+    assertRevokeResult(
+      { # One renewal
+        'service': [service2_serial1],
+      }, (
+        '--mode', 'service',
+        '--user-key', user0_key_path,
+        '--revoke-serial', service2_serial0,
+      ),
+    )
+    assertRevokeResult(
+      {}, ( # No renewals
+        '--mode', 'service',
+        '--revoke-crt', service1_key_path, '',
+      ),
+    )
+    assertRevokeResult(
+      {}, ( # Renewal is already revoked
+        '--mode', 'service',
+        '--user-key', user0_key_path,
+        '--revoke-serial', service1_serial0,
+      ),
+    )
+    assertRevokeResult(
+      { # renewal, 2 issued user certificates (one being the renewal of an
+        # already-revoked certificate), one issued service and its renewal,
+        # and the renewal of and already-revoked issued service certificate
+        'user': [
+          user0_serial1,
+          user1_serial,
+          user2_serial1,
+        ],
+        'service': [
+          service0_serial0, service0_serial1,
+          service2_serial1,
+        ],
+      }, (
+        '--mode', 'user',
+        '--user-key', user1_key_path,
+        '--revoke-serial', user0_serial0,
+      ),
+    )
+    assertRevokeResult(
+      { # 2 issued user certificates (one being the renewal of an
+        # already-revoked certificate), one issued service and its renewal,
+        # and the renewal of and already-revoked issued service certificate
+        'user': [
+          user1_serial,
+          user2_serial1,
+        ],
+        'service': [
+          service0_serial0, service0_serial1,
+          service2_serial1,
+        ],
+      }, (
+        '--mode', 'user',
+        '--revoke-crt', user0_key_path, '',
+      ),
+    )
+    # Duplicate revocations
+    # Must mention they are duplicate, but still display an updated view of
+    # descendant certificates.
+    assertRevokeResult(
+      { # 2 issued user certificates (one being the renewal of an
+        # already-revoked certificate), one issued service and its renewal,
+        # and the renewal of and already-revoked issued service certificate
+        'user': [
+          user1_serial,
+          user2_serial1,
+        ],
+        'service': [
+          service0_serial0, service0_serial1,
+          service2_serial1,
+        ],
+      }, (
+        '--mode', 'user',
+        '--user-key', user1_key_path,
+        '--revoke-serial', user0_serial0,
+      ),
+      already_revoked=True,
+    )
+    assertRevokeResult(
+      { # 2 issued user certificates (one being the renewal of an
+        # already-revoked certificate), one issued service and its renewal,
+        # and the renewal of and already-revoked issued service certificate
+        'user': [
+          user1_serial,
+          user2_serial1,
+        ],
+        'service': [
+          service0_serial0, service0_serial1,
+          service2_serial1,
+        ],
+      }, (
+        '--mode', 'user',
+        '--revoke-crt', user0_key_path, '',
+      ),
+      already_revoked=True,
+    )
+
 for property_id, property_value in CaucaseTest.__dict__.iteritems():
   if property_id.startswith('test') and callable(property_value):
     setattr(CaucaseTest, property_id, print_buffer_on_error(property_value))

caucase/utils.py

@@ -44,6 +44,7 @@ import cryptography.exceptions
 import pem
 from .exceptions import (
   CertificateVerificationError,
+  CertificateRevokedError,
   NotJSON,
 )
 
@@ -342,10 +343,12 @@ def _verifyCertificateChain(cert, trusted_cert_list, crl):
   Verifies whether certificate has been signed by any of the trusted
   certificates, is not revoked and is whithin its validity period.
 
-  Raises CertificateVerificationError if validation fails.
+  Raises CertificateVerificationError if validation fails, or its
+  CertificateRevokedError subclass if it is because this certificate was
+  revoked.
   """
   # Note: this function (validating a certificate without an SSL connection)
-  # does not seem to have many equivalents at all in python. OpenSSL module
+  # does not seem to have any equivalents at all in python. OpenSSL module
   # seems to be a rare implementation of it, so we keep using this module.
   # BUT it MUST NOT be used anywhere outside this function (hence the
   # bad-style local import). Use "cryptography".
@@ -362,13 +365,14 @@ def _verifyCertificateChain(cert, trusted_cert_list, crl):
       store,
       crypto.X509.from_cryptography(cert),
     ).verify_certificate()
-  except (
-    crypto.X509StoreContextError,
-    crypto.Error,
-  ) as e:
-    raise CertificateVerificationError(
-      'Certificate verification error: %s' % str(e),
-    )
+  except crypto.X509StoreContextError as e:
+    error, depth, _ = e.args[0]
+    # 23 is X509_V_ERR_CERT_REVOKED (include/openssl/x509_vfy.h)
+    if error == 23 and depth == 0:
+      raise CertificateRevokedError(repr(e))
+    raise CertificateVerificationError(repr(e))
+  except crypto.Error as e:
+    raise CertificateVerificationError(repr(e))
 
 def wrap(payload, key, digest):
   """

caucase/wsgi.py

@@ -23,6 +23,7 @@ Caucase - Certificate Authority for Users, Certificate Authority for SErvices
 """
 from __future__ import absolute_import
 from Cookie import SimpleCookie, CookieError
+from functools import partial
 import httplib
 import json
 import os
@@ -180,6 +181,7 @@ STATUS_OK = _getStatus(httplib.OK)
 STATUS_CREATED = _getStatus(httplib.CREATED)
 STATUS_NO_CONTENT = _getStatus(httplib.NO_CONTENT)
 STATUS_FOUND = _getStatus(httplib.FOUND)
+STATUS_CONFLICT = Conflict.status
 MAX_BODY_LENGTH = 10 * 1024 * 1024 # 10 MB
 
 class CORSTokenManager(object):
@@ -297,6 +299,7 @@ class Application(object):
       List of Origin values to always trust.
     """
     self._cau = cau
+    self._cas = cas
     self._http_url = http_url.rstrip('/')
     self._https_url = https_url.rstrip('/')
     self._cors_cookie_id = cors_cookie_id
@@ -577,8 +580,6 @@ class Application(object):
         raise
       except exceptions.NotFound:
         raise NotFound
-      except exceptions.Found:
-        raise Conflict
       except exceptions.NoStorage:
         raise InsufficientStorage
       except exceptions.NotJSON:
@@ -604,12 +605,12 @@ class Application(object):
     return result
 
   @staticmethod
-  def _returnFile(data, content_type, header_list=None):
+  def _returnFile(data, content_type, header_list=None, status=STATUS_OK):
     if header_list is None:
       header_list = []
     header_list.append(('Content-Type', content_type))
     header_list.append(('Content-Length', str(len(data))))
-    return (STATUS_OK, header_list, [data])
+    return (status, header_list, [data])
 
   @staticmethod
   def _getCSRID(subpath):
@@ -644,11 +645,12 @@ class Application(object):
     Verify user authentication.
 
     Raises SSLUnauthorized if authentication does not pass checks.
-    On success, appends a "Cache-Control" header.
+    On success, appends a "Cache-Control" header and returns certificate
+    object.
     """
     try:
       ca_list = self._cau.getCACertificateList()
-      utils.load_certificate(
+      result = utils.load_certificate(
         environ.get('SSL_CLIENT_CERT', b''),
         trusted_cert_list=ca_list,
         crl=utils.load_crl(
@@ -659,6 +661,7 @@ class Application(object):
     except (exceptions.CertificateVerificationError, ValueError):
       raise SSLUnauthorized
     header_list.append(('Cache-Control', 'private'))
+    return result
 
   def _readJSON(self, environ):
     """
@@ -1049,6 +1052,34 @@ class Application(object):
       'application/pkix-cert',
     )
 
+  def _getIssuedBy(self, context, serial):
+    """
+    Return a dict of non-revoked certificates descending from given serial.
+    Keys are modes, values are list of serials.
+    """
+    result = {}
+    if context is self._cau:
+      # Revoking a user certificate, list:
+      # - other user certificates it issued and their renewals
+      # - service certificates they issued and their renewals
+      user_serial_list = context.getIssuedBy([serial], False)
+      service_serial_list = self._cas.getNonRevokedCertificateSerialList(
+        self._cas.getIssuedBy([serial] + user_serial_list, False),
+      )
+      user_serial_list = context.getNonRevokedCertificateSerialList(
+        user_serial_list,
+      )
+      if user_serial_list:
+        result['user'] = user_serial_list
+    else:
+      # Revoking a service certificate, list its renewals.
+      service_serial_list = context.getNonRevokedCertificateSerialList(
+        context.getIssuedBy([serial], True),
+      )
+    if service_serial_list:
+      result['service'] = service_serial_list
+    return result
+
   def revokeCertificate(self, context, environ):
     """
     Handle PUT /{context}/crt/revoke .
@@ -1058,19 +1089,38 @@ class Application(object):
     if data['digest'] is None:
       self._authenticate(environ, header_list)
       payload = utils.nullUnwrap(data)
-      if 'revoke_crt_pem' not in payload:
-        context.revokeSerial(payload['revoke_serial'])
-        return (STATUS_NO_CONTENT, header_list, [])
+      if 'revoke_crt_pem' in payload:
+        crt_pem = utils.toBytes(payload['revoke_crt_pem'])
+        revoke = partial(context.revoke, crt_pem=crt_pem)
       else:
-      payload = utils.unwrap(
+        crt_pem = None
+        serial = payload['revoke_serial']
+        revoke = partial(context.revokeSerial, serial)
+    else:
+      crt_pem = utils.toBytes(utils.unwrap(
         data,
         lambda x: x['revoke_crt_pem'],
         context.digest_list,
+      )['revoke_crt_pem'])
+      revoke = partial(context.revoke, crt_pem=crt_pem)
+    if crt_pem is not None:
+      serial = utils.load_certificate(
+        crt_pem,
+        context.getCACertificateList(),
+        None, # context will check its revocation status
+      ).serial_number
+    try:
+      revoke()
+    except exceptions.Found:
+      status = STATUS_CONFLICT
+    else:
+      status = STATUS_OK
+    return self._returnFile(
+      json.dumps(self._getIssuedBy(context, serial)).encode('utf-8'),
+      'application/json',
+      header_list,
+      status,
     )
-    context.revoke(
-      crt_pem=utils.toBytes(payload['revoke_crt_pem']),
-    )
-    return (STATUS_NO_CONTENT, header_list, [])
 
   def renewCertificate(self, context, environ):
     """
@@ -1104,9 +1154,10 @@ class Application(object):
     else:
       raise BadRequest(b'Bad Content-Type')
     header_list = []
-    self._authenticate(environ, header_list)
+    user_crt = self._authenticate(environ, header_list)
     context.createCertificate(
       csr_id=crt_id,
       template_csr=template_csr,
+      authorisation_serial=user_crt.serial_number,
     )
     return (STATUS_NO_CONTENT, header_list, [])