Do not fail when an unusable key occurs (#762)

* Do not fail when a unusable key occurs

There may be more than keys in the store which may be (still usable).
Therefore we do not want to fail on any key that is not usable by pyjwt,
but rather skip when appending to the KeySet

* Add test cases with unusable 'alg' keys

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Add 'skip keys' to changelog

* Update CHANGELOG.rst

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

CHANGELOG.rst

@@ -9,6 +9,7 @@ This project adheres to `Semantic Versioning <https://semver.org/>`__.
 
 Changed
 ~~~~~~~
+- Skip keys with incompatible alg when loading JWKSet by @DaGuich in https://github.com/jpadilla/pyjwt/pull/762
 
 Fixed
 ~~~~~

jwt/api_jwk.py

@@ -84,7 +84,14 @@ def __init__(self, keys):
             raise PyJWKSetError("The JWK Set did not contain any keys")
 
         for key in keys:
-            self.keys.append(PyJWK(key))
+            try:
+                self.keys.append(PyJWK(key))
+            except PyJWKError:
+                # skip unusable keys
+                continue
+
+        if len(self.keys) == 0:
+            raise PyJWKSetError("The JWK Set did not contain any usable keys")
 
     @staticmethod
     def from_dict(obj):

tests/keys/jwk_keyset_only_unknown_alg.json

@@ -0,0 +1 @@
+{"keys":[{"kid":"lYXxnemSzWNBUoPug_h0hZnjPi5oKCmQ9awQJaZCWWM","kty":"RSA","alg":"RSA-OAEP","use":"enc","n":"k75Ghd4r8h_fdydTAXyMjrGYNnuiG7yevoW1ZIIuegEUK3LLGY0Z3Q8PhCrkmi6LpkPwwR1C8ck9plvSs4vZ9GqmUoi5YcQEile6HjPG3NBwQ-cHWY4ZH_D-ItdzcZUKDxjHYaY-GW1yLeJ1RAh8wMPM7cenA2v0eNIq4HaIXzZJ2Hgxh4Ei-CSYcD0f_TYEySqUEb8jd0dC8frpkYDkOUCVizRBDUEg_hkPSpVqfLP8ekxIHxkC9wcfL-d2FhptxBQYN8NFnIuG9NFXbZ5mdzdmIuN6WPr_CECcgL9qXsph9U-L829dU67ufeBvzEejJ8qwiswslRdx4ZcYjtaBdQ","e":"AQAB","x5c":["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"],"x5t":"FaWinuPZQiDMljn3x9DMAuepBYQ","x5t#S256":"_0B--Hh1KgNtdyZqAp1NWUAikRPvlt2HGm__xXpjTi0"}]}

tests/keys/jwk_keyset_with_unknown_alg.json

@@ -0,0 +1 @@
+{"keys":[{"kid":"U1MayerhVuRj8xtFR8hyMH9lCfVMKlb3TG7mbQAS19M","kty":"RSA","alg":"RS256","use":"sig","n":"omef3NkXf4--6BtUPKjhlV7pf6Vv7HMg-VL-ITX8KQZTD4LTzWO3x9RPwVepKjgfvJe_IiZFaJX78-a7zpcG9mpZG8czp3C8nZSvAJKphvYLd9s9qYrGMFW9t1eHyGwmIQN02VXwHeZ0JDd5X4i7sO4XPkNycfzSoxaQbv7wANYBTcvcWcjYVxIj4ZpYkSsQqrrOTm69G7FyurtfExGc7jlSRcv-Gubq_K3IQLHGHTlil20wqZmis1dLJwpAjgTxY7uQSwEdqJHCJR3q76bsDelIBZpbR07kqIOXqYu52w0wkC_1W7_HcVPLNp6T_ML09P8jGsOWfMO95_zchkseQw","e":"AQAB","x5c":["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"],"x5t":"0C94xr3ayzaC9OUcSSLyrwDGdmI","x5t#S256":"O6ntIrYkVK0hX-_AwnrwJW1CO97lP3D2_aKnELuNLSo"},{"kid":"lYXxnemSzWNBUoPug_h0hZnjPi5oKCmQ9awQJaZCWWM","kty":"RSA","alg":"RSA-OAEP","use":"enc","n":"k75Ghd4r8h_fdydTAXyMjrGYNnuiG7yevoW1ZIIuegEUK3LLGY0Z3Q8PhCrkmi6LpkPwwR1C8ck9plvSs4vZ9GqmUoi5YcQEile6HjPG3NBwQ-cHWY4ZH_D-ItdzcZUKDxjHYaY-GW1yLeJ1RAh8wMPM7cenA2v0eNIq4HaIXzZJ2Hgxh4Ei-CSYcD0f_TYEySqUEb8jd0dC8frpkYDkOUCVizRBDUEg_hkPSpVqfLP8ekxIHxkC9wcfL-d2FhptxBQYN8NFnIuG9NFXbZ5mdzdmIuN6WPr_CECcgL9qXsph9U-L829dU67ufeBvzEejJ8qwiswslRdx4ZcYjtaBdQ","e":"AQAB","x5c":["MIICnTCCAYUCBgGAUN05KzANBgkqhkiG9w0BAQsFADASMRAwDgYDVQQDDAdUZXN0aW5nMB4XDTIyMDQyMjEwNDAxN1oXDTMyMDQyMjEwNDE1N1owEjEQMA4GA1UEAwwHVGVzdGluZzCCASIwDQYJKoZIhvcNAQEBBQADggEPADCCAQoCggEBAJO+RoXeK/If33cnUwF8jI6xmDZ7ohu8nr6FtWSCLnoBFCtyyxmNGd0PD4Qq5Joui6ZD8MEdQvHJPaZb0rOL2fRqplKIuWHEBIpXuh4zxtzQcEPnB1mOGR/w/iLXc3GVCg8Yx2GmPhltci3idUQIfMDDzO3HpwNr9HjSKuB2iF82Sdh4MYeBIvgkmHA9H/02BMkqlBG/I3dHQvH66ZGA5DlAlYs0QQ1BIP4ZD0qVanyz/HpMSB8ZAvcHHy/ndhYabcQUGDfDRZyLhvTRV22eZnc3ZiLjelj6/whAnIC/al7KYfVPi/NvXVOu7n3gb8xHoyfKsIrMLJUXceGXGI7WgXUCAwEAATANBgkqhkiG9w0BAQsFAAOCAQEAeMUFrCX4eAfF8i6wILOP5dDJOBN10nPP63VNliQ7+YHu1ZI0VGB7TNrImRE9riH2IWenSXD21DxK31qBlZKNEgaH7rVwwvOZ22qCyWacv1+QdanxAiljD03rU7HOR/tyqcvjl6U2Yadxcq6OWlKKVaa0fNtbPigqAwQ3iVpg9N+OthANYyKHxlmzJKGeEaDA69/uJ6UwektHlv/9BnNFh8We6EwJxYG7/rejI02EgbJFxGO1RlcmigTxRc5l3Dw4WldBIRxWiJgSEkKSfUy5S7sQdFQokZjTyqy6h1ldb/tgrWLIE0srGQ2u/fQeSgPTbAzihaeOf+WKq5RDXoq5bw=="],"x5t":"FaWinuPZQiDMljn3x9DMAuepBYQ","x5t#S256":"_0B--Hh1KgNtdyZqAp1NWUAikRPvlt2HGm__xXpjTi0"}]}

tests/test_api_jwk.py

@@ -4,7 +4,7 @@
 
 from jwt.algorithms import has_crypto
 from jwt.api_jwk import PyJWK, PyJWKSet
-from jwt.exceptions import InvalidKeyError, PyJWKError
+from jwt.exceptions import InvalidKeyError, PyJWKError, PyJWKSetError
 
 from .utils import crypto_required, key_path
 
@@ -274,4 +274,22 @@ def test_keyset_should_index_by_kid(self):
         assert jwk == jwk_set["keyid-abc123"]
 
         with pytest.raises(KeyError):
-            jwk_set["this-kid-does-not-exist"]
+            _ = jwk_set["this-kid-does-not-exist"]
+
+    @crypto_required
+    def test_keyset_with_unknown_alg(self):
+        # first keyset with unusable key and usable key
+        with open(key_path("jwk_keyset_with_unknown_alg.json")) as keyfile:
+            jwks_text = keyfile.read()
+        jwks = json.loads(jwks_text)
+        assert len(jwks.get("keys")) == 2
+        keyset = PyJWKSet.from_json(jwks_text)
+        assert len(keyset.keys) == 1
+
+        # second keyset with only unusable key -> catch exception
+        with open(key_path("jwk_keyset_only_unknown_alg.json")) as keyfile:
+            jwks_text = keyfile.read()
+            jwks = json.loads(jwks_text)
+            assert len(jwks.get("keys")) == 1
+            with pytest.raises(PyJWKSetError):
+                _ = PyJWKSet.from_json(jwks_text)