new: satosa-saml-metadata: make signing optional

Allow skipping signing with --no-sign - and in that case, do not require key+cert.

Default to signing enabled (keep existing behaviour).

Mark key and cert args as optional in Click and instead check them explicitly
when signing is enabled.

Add new method create_entity_descriptor_metadata as counterpart
to create_signed_entity_descriptor to also apply `valid` option
to EntityDescriptor but avoid signing.

src/satosa/metadata_creation/saml_metadata.py

@@ -154,3 +154,18 @@ def create_signed_entity_descriptor(entity_descriptor, security_context, valid_f
         raise ValueError("Could not construct valid EntityDescriptor tag")
 
     return xmldoc
+
+
+def create_entity_descriptor_metadata(entity_descriptor, valid_for=None):
+    """
+    :param entity_descriptor: the entity descriptor to create metadata for
+    :param valid_for: number of hours the metadata should be valid
+    :return: the EntityDescriptor metadata
+
+    :type entity_descriptor: saml2.md.EntityDescriptor]
+    :type valid_for: Optional[int]
+    """
+    if valid_for:
+        entity_descriptor.valid_until = in_a_while(hours=valid_for)
+
+    return str(entity_descriptor)

src/satosa/scripts/satosa_saml_metadata.py

@@ -5,6 +5,7 @@
 from saml2.sigver import security_context
 
 from ..metadata_creation.saml_metadata import create_entity_descriptors
+from ..metadata_creation.saml_metadata import create_entity_descriptor_metadata
 from ..metadata_creation.saml_metadata import create_signed_entity_descriptor
 from ..satosa_config import SATOSAConfig
 
@@ -16,44 +17,58 @@ def _get_security_context(key, cert):
     return security_context(conf)
 
 
-def _create_split_entity_descriptors(entities, secc, valid):
+def _create_split_entity_descriptors(entities, secc, valid, sign=True):
     output = []
     for module_name, eds in entities.items():
         for i, ed in enumerate(eds):
-            output.append((create_signed_entity_descriptor(ed, secc, valid), "{}_{}.xml".format(module_name, i)))
+            ed_str = (
+                create_signed_entity_descriptor(ed, secc, valid)
+                if sign
+                else create_entity_descriptor_metadata(ed, valid)
+            )
+            output.append((ed_str, "{}_{}.xml".format(module_name, i)))
 
     return output
 
 
-def _create_merged_entities_descriptors(entities, secc, valid, name):
+def _create_merged_entities_descriptors(entities, secc, valid, name, sign=True):
     output = []
     frontend_entity_descriptors = [e for sublist in entities.values() for e in sublist]
     for frontend in frontend_entity_descriptors:
-        output.append((create_signed_entity_descriptor(frontend, secc, valid), name))
+        ed_str = (
+            create_signed_entity_descriptor(frontend, secc, valid)
+            if sign
+            else create_entity_descriptor_metadata(frontend, valid)
+        )
+        output.append((ed_str, name))
 
     return output
 
 
 def create_and_write_saml_metadata(proxy_conf, key, cert, dir, valid, split_frontend_metadata=False,
-                                   split_backend_metadata=False):
+                                   split_backend_metadata=False, sign=True):
     """
     Generates SAML metadata for the given PROXY_CONF, signed with the given KEY and associated CERT.
     """
     satosa_config = SATOSAConfig(proxy_conf)
-    secc = _get_security_context(key, cert)
+
+    if sign and (not key or not cert):
+        raise ValueError("Key and cert are required when signing")
+    secc = _get_security_context(key, cert) if sign else None
+
     frontend_entities, backend_entities = create_entity_descriptors(satosa_config)
 
     output = []
     if frontend_entities:
         if split_frontend_metadata:
-            output.extend(_create_split_entity_descriptors(frontend_entities, secc, valid))
+            output.extend(_create_split_entity_descriptors(frontend_entities, secc, valid, sign))
         else:
-            output.extend(_create_merged_entities_descriptors(frontend_entities, secc, valid, "frontend.xml"))
+            output.extend(_create_merged_entities_descriptors(frontend_entities, secc, valid, "frontend.xml", sign))
     if backend_entities:
         if split_backend_metadata:
-            output.extend(_create_split_entity_descriptors(backend_entities, secc, valid))
+            output.extend(_create_split_entity_descriptors(backend_entities, secc, valid, sign))
         else:
-            output.extend(_create_merged_entities_descriptors(backend_entities, secc, valid, "backend.xml"))
+            output.extend(_create_merged_entities_descriptors(backend_entities, secc, valid, "backend.xml", sign))
 
     for metadata, filename in output:
         path = os.path.join(dir, filename)
@@ -64,8 +79,8 @@ def create_and_write_saml_metadata(proxy_conf, key, cert, dir, valid, split_fron
 
 @click.command()
 @click.argument("proxy_conf")
-@click.argument("key")
-@click.argument("cert")
+@click.argument("key", required=False)
+@click.argument("cert", required=False)
 @click.option("--dir",
               type=click.Path(exists=True, file_okay=False, dir_okay=True, writable=True, readable=False,
                               resolve_path=False),
@@ -75,5 +90,7 @@ def create_and_write_saml_metadata(proxy_conf, key, cert, dir, valid, split_fron
               help="Create one entity descriptor per file for the frontend metadata")
 @click.option("--split-backend", is_flag=True, type=click.BOOL, default=False,
               help="Create one entity descriptor per file for the backend metadata")
-def construct_saml_metadata(proxy_conf, key, cert, dir, valid, split_frontend, split_backend):
-    create_and_write_saml_metadata(proxy_conf, key, cert, dir, valid, split_frontend, split_backend)
+@click.option("--sign/--no-sign", is_flag=True, type=click.BOOL, default=True,
+              help="Sign the generated metadata")
+def construct_saml_metadata(proxy_conf, key, cert, dir, valid, split_frontend, split_backend, sign):
+    create_and_write_saml_metadata(proxy_conf, key, cert, dir, valid, split_frontend, split_backend, sign)