Fix PEM data loading with cryptography >= 42

Author: lnagel

requirements.txt

@@ -1,4 +1,6 @@
-Django>=1.8
-djangorestframework>=3.2,<4.0
+cryptography
+Django
+djangorestframework
+pem
 PyJWT
-cryptography>=2.1.0,<4.0
+setuptools

rest_framework_sso/keys.py

@@ -1,6 +1,7 @@
 # coding: utf-8
 import os
 
+import pem
 from cryptography.hazmat.backends import default_backend
 from cryptography.hazmat.primitives.serialization import load_pem_private_key, load_pem_public_key
 from jwt.exceptions import InvalidKeyError
@@ -17,8 +18,7 @@ def read_key_file(file_name):
         file_path = os.path.abspath(os.path.join(api_settings.KEY_STORE_ROOT, file_name))
     else:
         file_path = os.path.abspath(file_name)
-    with open(file_path, "rb") as file_obj:
-        return file_obj.read()
+    return pem.parse_file(file_path)
 
 
 def get_key_id(file_name):
@@ -45,12 +45,20 @@ def get_key_file_name(keys, issuer, key_id=None):
 def get_private_key_and_key_id(issuer, key_id=None):
     file_name = get_key_file_name(keys=api_settings.PRIVATE_KEYS, issuer=issuer, key_id=key_id)
     file_data = read_key_file(file_name=file_name)
-    key = load_pem_private_key(file_data, password=None, backend=default_backend())
+    try:
+        key_data = next(o.as_bytes() for o in file_data if isinstance(o, pem.PrivateKey))
+    except StopIteration:
+        raise InvalidKeyError(f"No private key found for {issuer=} {key_id=}")
+    key = load_pem_private_key(key_data, password=None, backend=default_backend())
     return key, get_key_id(file_name=file_name)
 
 
 def get_public_key_and_key_id(issuer, key_id=None):
     file_name = get_key_file_name(keys=api_settings.PUBLIC_KEYS, issuer=issuer, key_id=key_id)
     file_data = read_key_file(file_name=file_name)
-    key = load_pem_public_key(file_data, backend=default_backend())
+    try:
+        key_data = next(o.as_bytes() for o in file_data if isinstance(o, pem.PublicKey))
+    except StopIteration:
+        raise InvalidKeyError(f"No public key found for {issuer=} {key_id=}")
+    key = load_pem_public_key(key_data, backend=default_backend())
     return key, get_key_id(file_name=file_name)

setup.py

@@ -3,7 +3,7 @@
 from setuptools import find_packages, setup
 
 
-INSTALL_REQUIRES = ["PyJWT>=1.5.2,<2.0.0"]
+INSTALL_REQUIRES = ["djangorestframework", "cryptography", "pem", "PyJWT"]
 
 
 with open(os.path.join(os.path.dirname(__file__), "README.rst")) as readme:
@@ -32,12 +32,9 @@
         "License :: OSI Approved :: MIT License",
         "Operating System :: OS Independent",
         "Programming Language :: Python",
-        "Programming Language :: Python :: 2",
-        "Programming Language :: Python :: 2.7",
-        "Programming Language :: Python :: 3",
-        "Programming Language :: Python :: 3.4",
-        "Programming Language :: Python :: 3.5",
-        "Programming Language :: Python :: 3.6",
+        "Programming Language :: Python :: 3.10",
+        "Programming Language :: Python :: 3.11",
+        "Programming Language :: Python :: 3.12",
         "Topic :: Internet :: WWW/HTTP",
         "Topic :: Internet :: WWW/HTTP :: Session",
         "Topic :: Software Development :: Libraries :: Python Modules",