From: Tobias Brunner <tobias@strongswan.org>
Date: Fri, 6 Dec 2024 10:33:37 +0000 (+0100)
Subject: vici: Delay creation of raw public keys until we know the identity
X-Git-Tag: android-2.5.3~36
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=65e121b49839f5afce2a8b725ffdd5f0a4914512;p=thirdparty%2Fstrongswan.git

vici: Delay creation of raw public keys until we know the identity

The previous approach had two drawbacks:

First, it caused duplicate public keys because when the `certificate_t`
object was created and added to the credential set it had no subject
assigned yet.  So it defaulted to the key ID.  However, all previously
loaded keys had their subject already changed to an identity, so there
never was a match and new objects were always added whenever a config
with raw public keys was loaded.

Second, the subject was replaced in a way that's not thread-safe on an
object that's already shared in the public credential set.  So other
threads could potentially access the `identification_t` object that's
destroyed during that process.

References strongswan/strongswan#853
Closes strongswan/strongswan#2561
---

diff --git a/src/libcharon/plugins/vici/vici_config.c b/src/libcharon/plugins/vici/vici_config.c
index e783b8f676..1a00424d63 100644
--- a/src/libcharon/plugins/vici/vici_config.c
+++ b/src/libcharon/plugins/vici/vici_config.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2015-2019 Tobias Brunner
+ * Copyright (C) 2015-2024 Tobias Brunner
  * Copyright (C) 2015-2018 Andreas Steffen
  * Copyright (C) 2014 Martin Willi
  *
@@ -295,6 +295,7 @@ static void free_cert_data(cert_data_t *data)
 typedef struct {
 	request_data_t *request;
 	auth_cfg_t *cfg;
+	array_t *pubkeys;
 	uint32_t round;
 } auth_data_t;
 
@@ -303,6 +304,7 @@ typedef struct {
  */
 static void free_auth_data(auth_data_t *data)
 {
+	array_destroy(data->pubkeys);
 	DESTROY_IF(data->cfg);
 	free(data);
 }
@@ -1573,16 +1575,36 @@ CALLBACK(parse_cacerts, bool,
  */
 CALLBACK(parse_pubkeys, bool,
 	auth_data_t *auth, chunk_t v)
+{
+	/* because we don't have an identity yet, just store the blob to parse/wrap
+	 * the key later */
+	array_insert_create_value(&auth->pubkeys, sizeof(chunk_t),
+							  ARRAY_TAIL, &v);
+	return TRUE;
+}
+
+/**
+ * Create raw public key certificates associated with the given identity and
+ * add them to the config.
+ */
+static bool parse_and_add_pubkeys(auth_data_t *auth, identification_t *id)
 {
 	certificate_t *cert;
+	chunk_t pubkey;
+	bool id_usable = id && id->get_type(id) != ID_ANY;
 
-	cert = lib->creds->create(lib->creds, CRED_CERTIFICATE, CERT_TRUSTED_PUBKEY,
-							  BUILD_BLOB, v, BUILD_END);
-	if (cert)
+	while (array_remove(auth->pubkeys, ARRAY_HEAD, &pubkey))
 	{
-		return add_cert(auth, AUTH_RULE_SUBJECT_CERT, cert);
+		cert = lib->creds->create(lib->creds, CRED_CERTIFICATE,
+								  CERT_TRUSTED_PUBKEY, BUILD_BLOB, pubkey,
+								  id_usable ? BUILD_SUBJECT : BUILD_END,
+								  id, BUILD_END);
+		if (!cert || !add_cert(auth, AUTH_RULE_SUBJECT_CERT, cert))
+		{
+			return FALSE;
+		}
 	}
-	return FALSE;
+	return TRUE;
 }
 
 /**
@@ -2202,11 +2224,8 @@ CALLBACK(peer_sn, bool,
 		enumerator_t *enumerator;
 		linked_list_t *auths;
 		auth_data_t *auth, *current;
-		auth_rule_t rule;
 		certificate_t *cert;
-		pubkey_cert_t *pubkey_cert;
 		identification_t *id;
-		bool default_id = FALSE;
 
 		INIT(auth,
 			.request = peer->request,
@@ -2220,29 +2239,23 @@ CALLBACK(peer_sn, bool,
 		}
 		id = auth->cfg->get(auth->cfg, AUTH_RULE_IDENTITY);
 
-		enumerator = auth->cfg->create_enumerator(auth->cfg);
-		while (enumerator->enumerate(enumerator, &rule, &cert))
+		if (!parse_and_add_pubkeys(auth, id))
+		{
+			free_auth_data(auth);
+			return FALSE;
+		}
+
+		if (!id)
 		{
-			if (rule == AUTH_RULE_SUBJECT_CERT && !default_id)
+			cert = auth->cfg->get(auth->cfg, AUTH_RULE_SUBJECT_CERT);
+			if (cert)
 			{
-				if (id == NULL)
-				{
-					id = cert->get_subject(cert);
-					DBG1(DBG_CFG, "  id not specified, defaulting to"
-								  " cert subject '%Y'", id);
-					auth->cfg->add(auth->cfg, AUTH_RULE_IDENTITY, id->clone(id));
-					default_id = TRUE;
-				}
-				else if (cert->get_type(cert) == CERT_TRUSTED_PUBKEY &&
-						 id->get_type(id) != ID_ANY)
-				{
-					/* set the subject of all raw public keys to the id */
-					pubkey_cert = (pubkey_cert_t*)cert;
-					pubkey_cert->set_subject(pubkey_cert, id);
-				}
+				id = cert->get_subject(cert);
+				DBG1(DBG_CFG, "  id not specified, defaulting to"
+							  " cert subject '%Y'", id);
+				auth->cfg->add(auth->cfg, AUTH_RULE_IDENTITY, id->clone(id));
 			}
 		}
-		enumerator->destroy(enumerator);
 
 		auths = strcasepfx(name, "local") ? peer->local : peer->remote;
 		enumerator = auths->create_enumerator(auths);