support for seamless rollover of OIDCCryptoPassphrase

using a (temporary) 2nd value that holds the old one; bump to 2.4.15rc1

Signed-off-by: Hans Zandbelt <hans.zandbelt@openidc.com>

ChangeLog

@@ -1,3 +1,7 @@
+10/31/2023
+- add capability to seamlessly rollover OIDCCryptoPassphrase using a (temporary) 2nd value that holds the old one
+- bump to 2.4.15rc1
+
 10/30/2023
 - do not apply logout_on_error and authenticate_on_error when a parallel refresh token request is detected
   see https://github.com/OpenIDC/mod_auth_openidc/discussions/1132; thanks @esunke

auth_openidc.conf

@@ -22,7 +22,12 @@
 #    OIDCCryptoPassphrase "exec:/bin/bash -c \"head /dev/urandom | tr -dc A-Za-z0-9 | head -c 32\""
 # (notice that the above typically only works in non-clustered environments)
 # The command may be absolute or relative to the web server root.
-#OIDCCryptoPassphrase [ <passphrase> | "exec:/path/to/otherProgram arg1" ]
+#
+# A second value can be used temporarily in case of passphrase rollover: the first (i.e. new) passphrase
+# will be used for encryption of new values (including a "kid" in the JWEs during the time 2 values are defined),
+# both values will be used for verification (leveraging the "kid" if present); for seamless rollover one should
+# (at minimum) wait for OIDCSessionInActivityTimeout seconds before removing the 2nd (i.e. old) passprase again.
+#OIDCCryptoPassphrase [ <passphrase> | "exec:/path/to/otherProgram arg1" ] [ <previous-passphrase> | "exec:/path/to/otherProgram arg2" ]
 
 #
 # All other entries below this are optional though some may be required in a

configure.ac

@@ -1,4 +1,4 @@
-AC_INIT([mod_auth_openidc],[2.4.15rc0],[hans.zandbelt@openidc.com])
+AC_INIT([mod_auth_openidc],[2.4.15rc1],[hans.zandbelt@openidc.com])
 
 AC_SUBST(NAMEVER, AC_PACKAGE_TARNAME()-AC_PACKAGE_VERSION())
 

src/cache/common.c

@@ -244,16 +244,20 @@ apr_byte_t oidc_cache_mutex_destroy(server_rec *s, oidc_cache_mutex_t *m) {
  * AES GCM encrypt using the crypto passphrase as symmetric key
  */
 static apr_byte_t oidc_cache_crypto_encrypt(request_rec *r,
-		const char *plaintext, const char *key, char **result) {
-	return oidc_util_jwt_create(r, key, plaintext, result);
+		const char *plaintext, const oidc_crypto_passphrase_t *passphrase,
+		char **result) {
+	return oidc_util_jwt_create(r, passphrase, plaintext, result);
 }
 
 /*
  * AES GCM decrypt using the crypto passphrase as symmetric key
  */
 static apr_byte_t oidc_cache_crypto_decrypt(request_rec *r,
-		const char *cache_value, const char *key, char **plaintext) {
-	return oidc_util_jwt_verify(r, key, cache_value, plaintext);
+		const char *cache_value, char *secret, char **plaintext) {
+	oidc_crypto_passphrase_t passphrase;
+	passphrase.secret1 = secret;
+	passphrase.secret2 = NULL;
+	return oidc_util_jwt_verify(r, &passphrase, cache_value, plaintext);
 }
 
 /*
@@ -283,39 +287,51 @@ apr_byte_t oidc_cache_get(request_rec *r, const char *section, const char *key,
 	int encrypted = oidc_cfg_cache_encrypt(r);
 	apr_byte_t rc = TRUE;
 	char *msg = NULL;
-	char *cache_value = NULL;
+	const char *s_key = NULL;
+	char *cache_value = NULL, *s_secret = NULL;
 
-	oidc_debug(r, "enter: %s (section=%s, decrypt=%d, type=%s)", key, section,
-			encrypted, cfg->cache->name);
+	oidc_debug(r, "enter: %s (section=%s, decrypt=%d, type=%s)", section,
+			section, encrypted, cfg->cache->name);
 
+	s_key = key;
 	/* see if encryption is turned on */
-	if (encrypted == 1)
-		key = oidc_cache_get_hashed_key(r, cfg->crypto_passphrase, key);
+	if (encrypted == 1) {
+		if (cfg->crypto_passphrase.secret1 == NULL) {
+			oidc_error(r,
+					"could not decrypt cache entry because " OIDCCryptoPassphrase " is not set");
+			goto out;
+		}
+		s_secret = cfg->crypto_passphrase.secret1;
+		s_key = oidc_cache_get_hashed_key(r, s_secret, key);
+	}
 
 	/* get the value from the cache */
-	if (cfg->cache->get(r, section, key, &cache_value) == FALSE) {
+	if (cfg->cache->get(r, section, s_key, &cache_value) == FALSE) {
 		rc = FALSE;
 		goto out;
 	}
 
 	/* see if it is any good */
-	if (cache_value == NULL)
-		goto out;
+	if (cache_value == NULL) {
+		if ((encrypted != 1) || (cfg->crypto_passphrase.secret2 == NULL)) {
+			rc = FALSE;
+			goto out;
+		}
+		s_secret = cfg->crypto_passphrase.secret2;
+		s_key = oidc_cache_get_hashed_key(r, s_secret, key);
+		if (cfg->cache->get(r, section, s_key, &cache_value) == FALSE) {
+			rc = FALSE;
+			goto out;
+		}
+	}
 
 	/* see if encryption is turned on */
 	if (encrypted == 0) {
 		*value = apr_pstrdup(r->pool, cache_value);
 		goto out;
 	}
 
-	if (cfg->crypto_passphrase == NULL) {
-		oidc_error(r,
-				"could not decrypt cache entry because " OIDCCryptoPassphrase " is not set");
-		goto out;
-	}
-
-	rc = oidc_cache_crypto_decrypt(r, cache_value, cfg->crypto_passphrase,
-			value);
+	rc = oidc_cache_crypto_decrypt(r, cache_value, s_secret, value);
 
 out:
 	/* log the result */
@@ -354,17 +370,18 @@ apr_byte_t oidc_cache_set(request_rec *r, const char *section, const char *key,
 	/* see if we need to encrypt */
 	if (encrypted == 1) {
 
-		key = oidc_cache_get_hashed_key(r, cfg->crypto_passphrase, key);
+		if (cfg->crypto_passphrase.secret1 == NULL) {
+			oidc_error(r,
+					"could not encrypt cache entry because " OIDCCryptoPassphrase " is not set");
+			goto out;
+		}
+
+		key = oidc_cache_get_hashed_key(r, cfg->crypto_passphrase.secret1, key);
 		if (key == NULL)
 			goto out;
 
 		if (value != NULL) {
-			if (cfg->crypto_passphrase == NULL) {
-				oidc_error(r,
-						"could not encrypt cache entry because " OIDCCryptoPassphrase " is not set");
-				goto out;
-			}
-			if (oidc_cache_crypto_encrypt(r, value, cfg->crypto_passphrase,
+			if (oidc_cache_crypto_encrypt(r, value, &cfg->crypto_passphrase,
 					&encoded) == FALSE)
 				goto out;
 			value = encoded;

src/config.c

@@ -598,14 +598,11 @@ static const char* oidc_set_outgoing_proxy_slot(cmd_parms *cmd, void *ptr,
 /*
  * set a string value in the server config with exec support
  */
-static const char* oidc_set_passphrase_slot(cmd_parms *cmd, void *struct_ptr,
-		const char *arg) {
-	oidc_cfg *cfg = (oidc_cfg*) ap_get_module_config(cmd->server->module_config,
-			&auth_openidc_module);
-	const char *passphrase = NULL;
-	int arglen = _oidc_strlen(arg);
+static const char* oidc_parse_passphrase(cmd_parms *cmd, const char *arg,
+		char **passphrase) {
 	char **argv = NULL;
 	char *result = NULL;
+	int arglen = _oidc_strlen(arg);
 	/* Based on code from mod_session_crypto. */
 	if (arglen > 5 && _oidc_strncmp(arg, "exec:", 5) == 0) {
 		if (apr_tokenize_to_argv(arg + 5, &argv, cmd->temp_pool) != APR_SUCCESS) {
@@ -626,12 +623,35 @@ static const char* oidc_set_passphrase_slot(cmd_parms *cmd, void *struct_ptr,
 		if (_oidc_strlen(result) == 0)
 			return apr_pstrdup(cmd->pool,
 					"the output of the crypto passphrase generation command is empty (perhaps you need to pass it to bash -c \"<cmd>\"?)");
-		passphrase = result;
+		*passphrase = apr_pstrdup(cmd->pool, result);
 	} else {
-		passphrase = arg;
+		*passphrase = apr_pstrdup(cmd->pool, arg);
 	}
+	return NULL;
+}
+
+static const char* oidc_set_crypto_passphrase_slot(cmd_parms *cmd,
+		void *struct_ptr, const char *arg1, const char *arg2) {
+	oidc_cfg *cfg = (oidc_cfg*) ap_get_module_config(cmd->server->module_config,
+			&auth_openidc_module);
+	const char *rv = NULL;
+	if (arg1)
+		rv = oidc_parse_passphrase(cmd, arg1, &cfg->crypto_passphrase.secret1);
+	if ((rv == NULL) && (arg2 != NULL))
+		rv = oidc_parse_passphrase(cmd, arg2, &cfg->crypto_passphrase.secret2);
+	return NULL;
+}
 
-	return ap_set_string_slot(cmd, cfg, passphrase);
+static const char* oidc_set_passphrase_slot(cmd_parms *cmd, void *struct_ptr,
+		const char *arg) {
+	oidc_cfg *cfg = (oidc_cfg*) ap_get_module_config(cmd->server->module_config,
+			&auth_openidc_module);
+	const char *rv = NULL;
+	char *secret = NULL;
+	rv = oidc_parse_passphrase(cmd, arg, &secret);
+	if (rv == NULL)
+		rv = ap_set_string_slot(cmd, cfg, secret);
+	return rv;
 }
 
 /*
@@ -1891,7 +1911,8 @@ void* oidc_create_server_config(apr_pool_t *pool, server_rec *svr) {
 	c->outgoing_proxy.username_password = NULL;
 	c->outgoing_proxy.auth_type = OIDC_CONFIG_POS_INT_UNSET;
 
-	c->crypto_passphrase = NULL;
+	c->crypto_passphrase.secret1 = NULL;
+	c->crypto_passphrase.secret2 = NULL;
 
 	c->error_template = NULL;
 	c->post_preserve_template = NULL;
@@ -2234,9 +2255,12 @@ void* oidc_merge_server_config(apr_pool_t *pool, void *BASE, void *ADD) {
 					add->outgoing_proxy.auth_type :
 					base->outgoing_proxy.auth_type;
 
-	c->crypto_passphrase =
-			add->crypto_passphrase != NULL ?
-					add->crypto_passphrase : base->crypto_passphrase;
+	c->crypto_passphrase.secret1 =
+			add->crypto_passphrase.secret1 != NULL ?
+					add->crypto_passphrase.secret1 : base->crypto_passphrase.secret1;
+	c->crypto_passphrase.secret2 =
+			add->crypto_passphrase.secret2 != NULL ?
+					add->crypto_passphrase.secret1 : base->crypto_passphrase.secret2;
 
 	c->error_template =
 			add->error_template != NULL ?
@@ -2693,7 +2717,7 @@ static int oidc_check_config_openid_openidc(server_rec *s, oidc_cfg *c) {
 		return oidc_check_config_error(s, OIDCRedirectURI);
 	redirect_uri_is_relative = (c->redirect_uri[0] == OIDC_CHAR_FORWARD_SLASH);
 
-	if (c->crypto_passphrase == NULL)
+	if (c->crypto_passphrase.secret1 == NULL)
 		return oidc_check_config_error(s, OIDCCryptoPassphrase);
 
 	if (c->metadata_dir == NULL) {
@@ -2787,7 +2811,7 @@ static int oidc_check_config_oauth(server_rec *s, oidc_cfg *c) {
 
 	}
 
-	if ((c->cache_encrypt == 1) && (c->crypto_passphrase == NULL))
+	if ((c->cache_encrypt == 1) && (c->crypto_passphrase.secret1 == NULL))
 		return oidc_check_config_error(s, OIDCCryptoPassphrase);
 
 	return OK;
@@ -3506,8 +3530,8 @@ const command_rec oidc_config_cmds[] = {
 				(void*)APR_OFFSETOF(oidc_cfg, outgoing_proxy),
 				RSRC_CONF,
 				"Specify an outgoing proxy for your network (<host>[:<port>]."),
-		AP_INIT_TAKE1(OIDCCryptoPassphrase,
-				oidc_set_passphrase_slot,
+		AP_INIT_TAKE12(OIDCCryptoPassphrase,
+				oidc_set_crypto_passphrase_slot,
 				(void*)APR_OFFSETOF(oidc_cfg, crypto_passphrase),
 				RSRC_CONF,
 				"Passphrase used for AES crypto on cookies and state."),

src/mod_auth_openidc.h

@@ -405,6 +405,11 @@ typedef struct oidc_http_timeout_t {
 	apr_time_t retry_interval;
 } oidc_http_timeout_t;
 
+typedef struct oidc_crypto_passphrase_t {
+	char *secret1;
+	char *secret2;
+} oidc_crypto_passphrase_t;
+
 typedef struct oidc_cfg {
 	/* indicates whether this is a derived config, merged from a base one */
 	unsigned int merged;
@@ -496,7 +501,7 @@ typedef struct oidc_cfg {
 
 	oidc_outgoing_proxy_t outgoing_proxy;
 
-	char *crypto_passphrase;
+	oidc_crypto_passphrase_t crypto_passphrase;
 
 	int provider_metadata_refresh_interval;
 
@@ -728,7 +733,7 @@ void oidc_proto_state_set_timestamp_now(oidc_proto_state_t *proto_state);
 
 apr_byte_t oidc_proto_token_endpoint_auth(request_rec *r, oidc_cfg *cfg, const char *token_endpoint_auth, const char *client_id, const char *client_secret, const apr_array_header_t *client_keys, const char *audience, apr_table_t *params, const char *bearer_access_token, char **basic_auth_str, char **bearer_auth_str);
 
-char *oidc_proto_peek_jwt_header(request_rec *r, const char *jwt, char **alg, char **enc);
+char *oidc_proto_peek_jwt_header(request_rec *r, const char *jwt, char **alg, char **enc, char **kid);
 int oidc_proto_authorization_request(request_rec *r, struct oidc_provider_t *provider, const char *login_hint, const char *redirect_uri, const char *state, oidc_proto_state_t *proto_state, const char *id_token_hint, const char *code_challenge, const char *auth_request_params, const char *path_scope);
 apr_byte_t oidc_proto_is_post_authorization_response(request_rec *r, oidc_cfg *cfg);
 apr_byte_t oidc_proto_is_redirect_authorization_response(request_rec *r, oidc_cfg *cfg);
@@ -892,8 +897,8 @@ apr_byte_t oidc_util_regexp_first_match(apr_pool_t *pool, const char *input, con
 apr_byte_t oidc_util_json_merge(request_rec *r, json_t *src, json_t *dst);
 int oidc_util_cookie_domain_valid(const char *hostname, char *cookie_domain);
 apr_byte_t oidc_util_hash_string_and_base64url_encode(request_rec *r, const char *openssl_hash_algo, const char *input, char **output);
-apr_byte_t oidc_util_jwt_create(request_rec *r, const char *secret, const char *s_payload, char **compact_encoded_jwt);
-apr_byte_t oidc_util_jwt_verify(request_rec *r, const char *secret, const char *compact_encoded_jwt, char **s_payload);
+apr_byte_t oidc_util_jwt_create(request_rec *r, const oidc_crypto_passphrase_t *passphrase, const char *s_payload, char **compact_encoded_jwt);
+apr_byte_t oidc_util_jwt_verify(request_rec *r, const oidc_crypto_passphrase_t *passphrase, const char *compact_encoded_jwt, char **s_payload);
 char *oidc_util_get_chunked_cookie(request_rec *r, const char *cookieName, int cookie_chunk_size);
 void oidc_util_set_chunked_cookie(request_rec *r, const char *cookieName, const char *cookieValue, apr_time_t expires, int chunkSize, const char *ext);
 apr_byte_t oidc_util_create_symmetric_key(request_rec *r, const char *client_secret, unsigned int r_key_len, const char *hash_algo, apr_byte_t set_kid, oidc_jwk_t **jwk);

src/oauth.c

@@ -573,7 +573,7 @@ static apr_byte_t oidc_oauth_validate_jwt_access_token(request_rec *r,
 		oidc_cfg *c, const char *access_token, json_t **token, char **response) {
 
 	oidc_debug(r, "enter: JWT access_token header=%s",
-			oidc_proto_peek_jwt_header(r, access_token, NULL, NULL));
+			oidc_proto_peek_jwt_header(r, access_token, NULL, NULL, NULL));
 
 	oidc_jose_error_t err;
 	oidc_jwk_t *jwk = NULL;

src/proto.c

@@ -464,7 +464,7 @@ char* oidc_proto_create_request_object(request_rec *r,
 	json_decref(request_object_config);
 
 	oidc_debug(r, "serialized request object JWT header = \"%s\"",
-			oidc_proto_peek_jwt_header(r, serialized_request_object, NULL, NULL));
+			oidc_proto_peek_jwt_header(r, serialized_request_object, NULL, NULL, NULL));
 	oidc_debug(r, "serialized request object = \"%s\"",
 			serialized_request_object);
 
@@ -967,7 +967,7 @@ void oidc_proto_state_destroy(oidc_proto_state_t *proto_state) {
 
 apr_byte_t oidc_proto_check_crypto_passphrase(request_rec *r, oidc_cfg *c,
 		const char *action) {
-	if (c->crypto_passphrase == NULL) {
+	if (c->crypto_passphrase.secret1 == NULL) {
 		oidc_error(r,
 				"cannot %s state cookie because " OIDCCryptoPassphrase " is not set; please check your OIDC Provider configuration as well or avoid using AuthType openid-connect",
 				action);
@@ -982,7 +982,7 @@ oidc_proto_state_t* oidc_proto_state_from_cookie(request_rec *r, oidc_cfg *c,
 	json_t *result = NULL;
 	if (oidc_proto_check_crypto_passphrase(r, c, "parse") == FALSE)
 		return NULL;
-	oidc_util_jwt_verify(r, c->crypto_passphrase, cookieValue, &s_payload);
+	oidc_util_jwt_verify(r, &c->crypto_passphrase, cookieValue, &s_payload);
 	oidc_util_decode_json_object(r, s_payload, &result);
 	return result;
 }
@@ -992,7 +992,7 @@ char* oidc_proto_state_to_cookie(request_rec *r, oidc_cfg *c,
 	char *cookieValue = NULL;
 	if (oidc_proto_check_crypto_passphrase(r, c, "create") == FALSE)
 		return NULL;
-	oidc_util_jwt_create(r, c->crypto_passphrase,
+	oidc_util_jwt_create(r, &c->crypto_passphrase,
 			oidc_util_encode_json_object(r, proto_state, JSON_COMPACT),
 			&cookieValue);
 	return cookieValue;
@@ -1637,7 +1637,7 @@ apr_byte_t oidc_proto_jwt_verify(request_rec *r, oidc_cfg *cfg, oidc_jwt_t *jwt,
  * return the compact-encoded JWT header contents
  */
 char* oidc_proto_peek_jwt_header(request_rec *r,
-		const char *compact_encoded_jwt, char **alg, char **enc) {
+		const char *compact_encoded_jwt, char **alg, char **enc, char **kid) {
 	char *input = NULL, *result = NULL;
 	char *p = strstr(compact_encoded_jwt ? compact_encoded_jwt : "", ".");
 	if (p == NULL) {
@@ -1663,6 +1663,10 @@ char* oidc_proto_peek_jwt_header(request_rec *r,
 				*enc = apr_pstrdup(r->pool,
 						json_string_value(
 								json_object_get(json, CJOSE_HDR_ENC)));
+			if (kid)
+				*kid = apr_pstrdup(r->pool,
+						json_string_value(
+								json_object_get(json, CJOSE_HDR_KID)));
 		}
 		json_decref(json);
 	}
@@ -1678,7 +1682,7 @@ apr_byte_t oidc_proto_parse_idtoken(request_rec *r, oidc_cfg *cfg,
 
 	char *alg = NULL;
 	oidc_debug(r, "enter: id_token header=%s",
-			oidc_proto_peek_jwt_header(r, id_token, &alg, NULL));
+			oidc_proto_peek_jwt_header(r, id_token, &alg, NULL, NULL));
 	apr_hash_t *decryption_keys = NULL;
 
 	char buf[APR_RFC822_DATE_LEN + 1];
@@ -2179,7 +2183,7 @@ static apr_byte_t oidc_user_info_response_validate(request_rec *r,
 			|| (provider->userinfo_encrypted_response_alg != NULL)
 			|| (provider->userinfo_encrypted_response_enc != NULL)) {
 		oidc_debug(r, "JWT header=%s",
-				oidc_proto_peek_jwt_header(r, *response, &alg, NULL));
+				oidc_proto_peek_jwt_header(r, *response, &alg, NULL, NULL));
 	}
 
 	oidc_jose_error_t err;