ike-sa: Add method to verify certificates in completed authentication rounds

src/libcharon/sa/ike_sa.c

@@ -58,6 +58,7 @@
 #include <sa/ikev2/tasks/ike_auth_lifetime.h>
 #include <sa/ikev2/tasks/ike_reauth_complete.h>
 #include <sa/ikev2/tasks/ike_redirect.h>
+#include <credentials/sets/auth_cfg_wrapper.h>
 
 #ifdef ME
 #include <sa/ikev2/tasks/ike_me.h>
@@ -462,6 +463,107 @@ METHOD(ike_sa_t, create_auth_cfg_enumerator, enumerator_t*,
 	return array_create_enumerator(this->other_auths);
 }
 
+METHOD(ike_sa_t, verify_peer_certificate, bool,
+	private_ike_sa_t *this)
+{
+	enumerator_t *e1, *e2, *certs;
+	auth_cfg_t *cfg, *cfg_done;
+	certificate_t *peer, *cert;
+	public_key_t *key;
+	auth_cfg_t *auth;
+	auth_cfg_wrapper_t *wrapper;
+	time_t not_before, not_after;
+	bool valid = TRUE, found;
+
+	if (this->state != IKE_ESTABLISHED)
+	{
+		DBG1(DBG_IKE, "unable to verify peer certificate in state %N",
+			 ike_sa_state_names, this->state);
+		return FALSE;
+	}
+
+	if (lib->settings->get_bool(lib->settings,
+								"%s.flush_auth_cfg", FALSE, lib->ns))
+	{
+		DBG1(DBG_IKE, "unable to verify peer certificate as authentication "
+			 "information has been flushed");
+		return FALSE;
+	}
+
+	e1 = this->peer_cfg->create_auth_cfg_enumerator(this->peer_cfg, FALSE);
+	e2 = array_create_enumerator(this->other_auths);
+	while (e1->enumerate(e1, &cfg))
+	{
+		if (!e2->enumerate(e2, &cfg_done))
+		{	/* this should not happen as the authentication should never have
+			 * succeeded */
+			valid = FALSE;
+			break;
+		}
+		if ((uintptr_t)cfg_done->get(cfg_done,
+									 AUTH_RULE_AUTH_CLASS) != AUTH_CLASS_PUBKEY)
+		{
+			continue;
+		}
+		peer = cfg_done->get(cfg_done, AUTH_RULE_SUBJECT_CERT);
+		if (!peer)
+		{
+			DBG1(DBG_IKE, "no subject certificate found, skipping certificate "
+				 "verification");
+			continue;
+		}
+		if (!peer->get_validity(peer, NULL, &not_before, &not_after))
+		{
+			/* FIXME: theoretically we could find a newer cert with the same
+			 * identity and public key below...but it's not the cert used by
+			 * the peer during the original authentication so... */
+			DBG1(DBG_IKE, "peer certificate invalid (valid from %T to %T)",
+				 &not_before, FALSE, &not_after, FALSE);
+			valid = FALSE;
+			break;
+		}
+		key = peer->get_public_key(peer);
+		if (!key)
+		{
+			DBG1(DBG_IKE, "unable to retrieve public key, skipping certificate "
+				 "verification");
+			continue;
+		}
+		DBG1(DBG_IKE, "verifying peer certificate");
+		/* serve received certificates */
+		wrapper = auth_cfg_wrapper_create(cfg_done);
+		lib->credmgr->add_local_set(lib->credmgr, &wrapper->set, FALSE);
+		certs = lib->credmgr->create_trusted_enumerator(lib->credmgr,
+							key->get_type(key), peer->get_subject(peer), TRUE);
+		key->destroy(key);
+
+		found = FALSE;
+		while (certs->enumerate(certs, &cert, &auth))
+		{
+			if (peer->equals(peer, cert))
+			{
+				cfg_done->add(cfg_done, AUTH_RULE_CERT_VALIDATION_SUSPENDED,
+							  FALSE);
+				cfg_done->merge(cfg_done, auth, FALSE);
+				valid = cfg_done->complies(cfg_done, cfg, TRUE);
+				found = TRUE;
+				break;
+			}
+		}
+		certs->destroy(certs);
+		lib->credmgr->remove_local_set(lib->credmgr, &wrapper->set);
+		wrapper->destroy(wrapper);
+		if (!found || !valid)
+		{
+			valid = FALSE;
+			break;
+		}
+	}
+	e1->destroy(e1);
+	e2->destroy(e2);
+	return valid;
+}
+
 /**
  * Flush the stored authentication round information
  */
@@ -2750,6 +2852,7 @@ ike_sa_t * ike_sa_create(ike_sa_id_t *ike_sa_id, bool initiator,
 			.set_peer_cfg = _set_peer_cfg,
 			.get_auth_cfg = _get_auth_cfg,
 			.create_auth_cfg_enumerator = _create_auth_cfg_enumerator,
+			.verify_peer_certificate = _verify_peer_certificate,
 			.add_auth_cfg = _add_auth_cfg,
 			.get_proposal = _get_proposal,
 			.set_proposal = _set_proposal,

src/libcharon/sa/ike_sa.h

@@ -521,6 +521,14 @@ struct ike_sa_t {
 	 */
 	enumerator_t* (*create_auth_cfg_enumerator)(ike_sa_t *this, bool local);
 
+	/**
+	 * Verify the trustchains (validity, revocation) in completed public key
+	 * auth rounds.
+	 *
+	 * @return				TRUE if certificates were valid, FALSE otherwise
+	 */
+	bool (*verify_peer_certificate)(ike_sa_t *this);
+
 	/**
 	 * Get the selected proposal of this IKE_SA.
 	 *