enforce OIDCIDTokenSignedResponseAlg and OIDCUserInfoSignedResponseAlg

see #435; bump to 2.4.1rc2

Signed-off-by: Hans Zandbelt <[email protected]>

ChangeLog

@@ -1,5 +1,7 @@
 12/09/2019
 - fix parsing of values from metadata files when the default is non-NULL (e.g. UNSET)
+- enforce OIDCIDTokenSignedResponseAlg and OIDCUserInfoSignedResponseAlg; see #435
+- bump to 2.4.1rc2
 
 12/05/2019
 - add the possibility to use a public key instead of a certificate for OIDCPublicKeyFiles parameter

configure.ac

@@ -1,4 +1,4 @@
-AC_INIT([mod_auth_openidc],[2.4.1rc1],[[email protected]])
+AC_INIT([mod_auth_openidc],[2.4.1rc2],[[email protected]])
 
 AC_SUBST(NAMEVER, AC_PACKAGE_TARNAME()-AC_PACKAGE_VERSION())
 

src/config.c

@@ -2578,7 +2578,7 @@ const command_rec oidc_config_cmds[] = {
 				oidc_set_signed_response_alg,
 				(void *)APR_OFFSETOF(oidc_cfg, provider.id_token_signed_response_alg),
 				RSRC_CONF,
-				"The algorithm that the OP should use to sign the id_token (used only in dynamic client registration); must be one of [RS256|RS384|RS512|PS256|PS384|PS512|HS256|HS384|HS512]"),
+				"The algorithm that the OP must use to sign the ID token."),
 		AP_INIT_TAKE1(OIDCIDTokenEncryptedResponseAlg,
 				oidc_set_encrypted_response_alg,
 				(void *)APR_OFFSETOF(oidc_cfg, provider.id_token_encrypted_response_alg),

src/mod_auth_openidc.c

@@ -666,7 +666,7 @@ static apr_byte_t oidc_unsolicited_proto_state(request_rec *r, oidc_cfg *c,
 	oidc_jwks_uri_t jwks_uri = { provider->jwks_uri,
 			provider->jwks_refresh_interval, provider->ssl_validate_server };
 	if (oidc_proto_jwt_verify(r, c, jwt, &jwks_uri,
-			oidc_util_merge_symmetric_key(r->pool, NULL, jwk)) == FALSE) {
+			oidc_util_merge_symmetric_key(r->pool, NULL, jwk), NULL) == FALSE) {
 		oidc_error(r, "state JWT could not be validated, aborting");
 		oidc_jwt_destroy(jwt);
 		return FALSE;
@@ -2894,7 +2894,8 @@ static int oidc_handle_logout_backchannel(request_rec *r, oidc_cfg *cfg) {
 	oidc_jwks_uri_t jwks_uri = { provider->jwks_uri,
 			provider->jwks_refresh_interval, provider->ssl_validate_server };
 	if (oidc_proto_jwt_verify(r, cfg, jwt, &jwks_uri,
-			oidc_util_merge_symmetric_key(r->pool, NULL, jwk)) == FALSE) {
+			oidc_util_merge_symmetric_key(r->pool, NULL, jwk),
+			provider->id_token_signed_response_alg) == FALSE) {
 
 		oidc_error(r, "id_token signature could not be validated, aborting");
 		goto out;

src/mod_auth_openidc.h

@@ -639,7 +639,7 @@ int oidc_proto_javascript_implicit(request_rec *r, oidc_cfg *c);
 apr_array_header_t *oidc_proto_supported_flows(apr_pool_t *pool);
 apr_byte_t oidc_proto_flow_is_supported(apr_pool_t *pool, const char *flow);
 apr_byte_t oidc_proto_validate_authorization_response(request_rec *r, const char *response_type, const char *requested_response_mode, char **code, char **id_token, char **access_token, char **token_type, const char *used_response_mode);
-apr_byte_t oidc_proto_jwt_verify(request_rec *r, oidc_cfg *cfg, oidc_jwt_t *jwt, const oidc_jwks_uri_t *jwks_uri, apr_hash_t *symmetric_keys);
+apr_byte_t oidc_proto_jwt_verify(request_rec *r, oidc_cfg *cfg, oidc_jwt_t *jwt, const oidc_jwks_uri_t *jwks_uri, apr_hash_t *symmetric_keys, const char *alg);
 apr_byte_t oidc_proto_validate_jwt(request_rec *r, oidc_jwt_t *jwt, const char *iss, apr_byte_t exp_is_mandatory, apr_byte_t iat_is_mandatory, int iat_slack, int token_binding_policy);
 apr_byte_t oidc_proto_generate_nonce(request_rec *r, char **nonce, int len);
 apr_byte_t oidc_proto_validate_aud_and_azp(request_rec *r, oidc_cfg *cfg, oidc_provider_t *provider, oidc_jwt_payload_t *id_token_payload);

src/oauth.c

@@ -642,7 +642,7 @@ static apr_byte_t oidc_oauth_validate_jwt_access_token(request_rec *r,
 			c->provider.jwks_refresh_interval, c->oauth.ssl_validate_server };
 	if (oidc_proto_jwt_verify(r, c, jwt, &jwks_uri,
 			oidc_util_merge_key_sets(r->pool, c->oauth.verify_public_keys,
-					c->oauth.verify_shared_keys)) == FALSE) {
+					c->oauth.verify_shared_keys), NULL) == FALSE) {
 		oidc_error(r,
 				"JWT access token signature could not be validated, aborting");
 		oidc_jwt_destroy(jwt);

src/proto.c

@@ -1530,10 +1530,22 @@ apr_byte_t oidc_proto_get_keys_from_jwks_uri(request_rec *r, oidc_cfg *cfg,
  * verify the signature on a JWT using the dynamically obtained and statically configured keys
  */
 apr_byte_t oidc_proto_jwt_verify(request_rec *r, oidc_cfg *cfg, oidc_jwt_t *jwt,
-		const oidc_jwks_uri_t *jwks_uri, apr_hash_t *static_keys) {
+		const oidc_jwks_uri_t *jwks_uri, apr_hash_t *static_keys,
+		const char *alg) {
 
 	oidc_jose_error_t err;
-	apr_hash_t *dynamic_keys = apr_hash_make(r->pool);
+	apr_hash_t *dynamic_keys = NULL;
+
+	if (alg != NULL) {
+		if (apr_strnatcmp(jwt->header.alg, alg) != 0) {
+			oidc_error(r,
+					"JWT was not signed with the expected configured algorithm: %s != %s",
+					jwt->header.alg, alg);
+			return FALSE;
+		}
+	}
+
+	dynamic_keys = apr_hash_make(r->pool);
 
 	/* see if we've got a JWKs URI set for signature validation with dynamically obtained asymmetric keys */
 	if (jwks_uri->url == NULL) {
@@ -1650,7 +1662,8 @@ apr_byte_t oidc_proto_parse_idtoken(request_rec *r, oidc_cfg *cfg,
 		oidc_jwks_uri_t jwks_uri = { provider->jwks_uri,
 				provider->jwks_refresh_interval, provider->ssl_validate_server };
 		if (oidc_proto_jwt_verify(r, cfg, *jwt, &jwks_uri,
-				oidc_util_merge_symmetric_key(r->pool, NULL, jwk)) == FALSE) {
+				oidc_util_merge_symmetric_key(r->pool, NULL, jwk),
+				provider->id_token_signed_response_alg) == FALSE) {
 
 			oidc_error(r,
 					"id_token signature could not be validated, aborting");
@@ -2150,7 +2163,8 @@ static apr_byte_t oidc_user_info_response_validate(request_rec *r,
 		oidc_jwks_uri_t jwks_uri = { provider->jwks_uri,
 				provider->jwks_refresh_interval, provider->ssl_validate_server };
 		if (oidc_proto_jwt_verify(r, cfg, jwt, &jwks_uri,
-				oidc_util_merge_symmetric_key(r->pool, NULL, jwk)) == FALSE) {
+				oidc_util_merge_symmetric_key(r->pool, NULL, jwk),
+				provider->userinfo_signed_response_alg) == FALSE) {
 
 			oidc_error(r, "JWT signature could not be validated, aborting");
 			oidc_jwt_destroy(jwt);