libtls: Enforce client/server identity when looking for public key

The client already enforces that the server identity is contained in the
received certificate.  But on the server, the referenced commit changed
the lookup from the configured (or adopted if %any was configured) client
identity to the subject DN of the received client certificate.  So any
client with a trusted certificate was accepted.

Fixes: d2fc9b0961c6 ("tls-server: Mutual authentication support for TLS 1.3")
Closes strongswan/strongswan#873

diff --git a/src/libtls/tls_peer.c b/src/libtls/tls_peer.c
index f3854eba5265426b1f21cfe07d9717ca6b5345cc..58a36dbd2d55d3cab09a3d039eef5593344b4232 100644 (file)
--- a/src/libtls/tls_peer.c
+++ b/src/libtls/tls_peer.c
@@ -165,7 +165,7 @@ struct private_tls_peer_t {
 
 /* Implemented in tls_server.c */
 bool tls_write_key_share(bio_writer_t **key_share, diffie_hellman_t *dh);
-public_key_t *tls_find_public_key(auth_cfg_t *peer_auth);
+public_key_t *tls_find_public_key(auth_cfg_t *peer_auth, identification_t *id);
 
 /**
  * Verify the DH group/key type requested by the server is valid.
@@ -641,7 +641,7 @@ static status_t process_cert_verify(private_tls_peer_t *this,
        public_key_t *public;
        chunk_t msg;
 
-       public = tls_find_public_key(this->server_auth);
+       public = tls_find_public_key(this->server_auth, this->server);
        if (!public)
        {
                DBG1(DBG_TLS, "no trusted certificate found for '%Y' to verify TLS server",
@@ -690,7 +690,7 @@ static status_t process_modp_key_exchange(private_tls_peer_t *this,
                this->alert->add(this->alert, TLS_FATAL, TLS_INTERNAL_ERROR);
                return NEED_MORE;
        }
-       public = tls_find_public_key(this->server_auth);
+       public = tls_find_public_key(this->server_auth, this->server);
        if (!public)
        {
                DBG1(DBG_TLS, "no TLS public key found for server '%Y'", this->server);
@@ -797,7 +797,7 @@ static status_t process_ec_key_exchange(private_tls_peer_t *this,
                return NEED_MORE;
        }
 
-       public = tls_find_public_key(this->server_auth);
+       public = tls_find_public_key(this->server_auth, this->server);
        if (!public)
        {
                DBG1(DBG_TLS, "no TLS public key found for server '%Y'", this->server);
@@ -1621,7 +1621,7 @@ static status_t send_key_exchange_encrypt(private_tls_peer_t *this,
                return NEED_MORE;
        }
 
-       public = tls_find_public_key(this->server_auth);
+       public = tls_find_public_key(this->server_auth, this->server);
        if (!public)
        {
                DBG1(DBG_TLS, "no TLS public key found for server '%Y'", this->server);

diff --git a/src/libtls/tls_server.c b/src/libtls/tls_server.c
index bbfe542496c35cddb48aed8571e2cadb1fe99d84..4efe04e0828695df4d61ed6dcdb7f0961cef5989 100644 (file)
--- a/src/libtls/tls_server.c
+++ b/src/libtls/tls_server.c
@@ -173,7 +173,7 @@ struct private_tls_server_t {
 /**
  * Find a trusted public key to encrypt/verify key exchange data
  */
-public_key_t *tls_find_public_key(auth_cfg_t *peer_auth)
+public_key_t *tls_find_public_key(auth_cfg_t *peer_auth, identification_t *id)
 {
        public_key_t *public = NULL, *current;
        certificate_t *cert, *found;
@@ -184,8 +184,7 @@ public_key_t *tls_find_public_key(auth_cfg_t *peer_auth)
        if (cert)
        {
                enumerator = lib->credmgr->create_public_enumerator(lib->credmgr,
-                                                                                       KEY_ANY, cert->get_subject(cert),
-                                                                                       peer_auth, TRUE);
+                                                                                               KEY_ANY, id, peer_auth, TRUE);
                while (enumerator->enumerate(enumerator, &current, &auth))
                {
                        found = auth->get(auth, AUTH_RULE_SUBJECT_CERT);
@@ -923,7 +922,7 @@ static status_t process_cert_verify(private_tls_server_t *this,
        public_key_t *public;
        chunk_t msg;
 
-       public = tls_find_public_key(this->peer_auth);
+       public = tls_find_public_key(this->peer_auth, this->peer);
        if (!public)
        {
                DBG1(DBG_TLS, "no trusted certificate found for '%Y' to verify TLS peer",