Add \r\n check for SSH keys in Azure (#889)

See https://bugs.launchpad.net/cloud-init/+bug/1910835

cloudinit/sources/DataSourceAzure.py

@@ -1551,6 +1551,9 @@ def _key_is_openssh_formatted(key):
     """
     Validate whether or not the key is OpenSSH-formatted.
     """
+    # See https://bugs.launchpad.net/cloud-init/+bug/1910835
+    if '\r\n' in key.strip():
+        return False
 
     parser = ssh_util.AuthKeyLineParser()
     try:

tests/unittests/test_datasource/test_azure.py

@@ -1764,6 +1764,18 @@ def test_get_public_ssh_keys_with_imds(self, m_parse_certificates):
         self.assertEqual(ssh_keys, ["ssh-rsa key1"])
         self.assertEqual(m_parse_certificates.call_count, 0)
 
+    def test_key_without_crlf_valid(self):
+        test_key = 'ssh-rsa somerandomkeystuff some comment'
+        assert True is dsaz._key_is_openssh_formatted(test_key)
+
+    def test_key_with_crlf_invalid(self):
+        test_key = 'ssh-rsa someran\r\ndomkeystuff some comment'
+        assert False is dsaz._key_is_openssh_formatted(test_key)
+
+    def test_key_endswith_crlf_valid(self):
+        test_key = 'ssh-rsa somerandomkeystuff some comment\r\n'
+        assert True is dsaz._key_is_openssh_formatted(test_key)
+
     @mock.patch(
         'cloudinit.sources.helpers.azure.OpenSSLManager.parse_certificates')
     @mock.patch(MOCKPATH + 'get_metadata_from_imds')