Validator chains now exit on the first error

Also, added some more robust error handling for buggy validators.
A broken validator will now cause Anchor to fail-closed and deny
a certificate, exactly as if that validator test had failed
normally.

A message is logged giving information about the error and a 500
is returned to the calling service with minimal information.

Change-Id: Iddbd0e831a52cc02cc569f220aebf82bd59554d0

anchor/certificate_ops.py

@@ -106,20 +106,22 @@ def validate_csr(auth_result, csr, request):
     # so we set the initial state to valid.
     valid = True
 
-    for name, vset in jsonloader.conf.validators.iteritems():
-        logger.debug("validate_csr: checking {}".format(name))
+    try:
+        for name, vset in jsonloader.conf.validators.iteritems():
+            logger.debug("validate_csr: checking with set {}".format(name))
+            for vname, validator in vset.iteritems():
+                valid = _run_validator(vname, validator, args)
+                if not valid:
+                    break  # early out at the first error
 
-        results = [_run_validator(x, y, args) for x, y in vset.iteritems()]
-        results.append(valid)  # track previous failures
-        valid = all(results)
-
-    # valid here says that either (1) we didn't run any tests, or (2) we
-    # ran some tests and they all passed. Either way, we can just return.
-    if valid:
-        return
+    except Exception as e:
+        logger.exception("Error running validator <%s> - %s", vname, e)
+        pecan.abort(500, "Internal Validation Error running validator "
+                         "'{}' in set '{}'".format(vname, name))
 
     # something failed, return a 400 to the client
-    pecan.abort(400, "CSR failed validation")
+    if not valid:
+        pecan.abort(400, "CSR failed validation")
 
 
 def sign(csr):

tests/test_functional.py

@@ -25,6 +25,7 @@ import pecan
 from pecan import testing as pecan_testing
 
 from anchor import jsonloader
+from anchor import validators
 from anchor.X509 import certificate as X509_cert
 import config
 
@@ -154,3 +155,21 @@ class TestFunctional(unittest.TestCase):
         # make sure the cert was issued by anchor
         self.assertEqual("/C=UK/ST=Some-State/O=OSSG/CN=anchor.example.com",
                          str(cert.get_issuer()))
+
+    def test_check_broken_validator(self):
+        data = {'user': 'myusername',
+                'secret': 'simplepassword',
+                'encoding': 'pem',
+                'csr': TestFunctional.csr_good}
+
+        def derp(**kwdargs):
+            raise Exception("BOOM")
+
+        validators.broken_validator = derp
+        jsonloader.conf.validators["default"]["broken_validator"] = {}
+
+        resp = self.app.post('/sign', data, expect_errors=True)
+        self.assertEqual(500, resp.status_int)
+        self.assertTrue(("Internal Validation Error running "
+                         "validator 'broken_validator' "
+                         "in set 'default'") in str(resp))