Commit e059077d3f for strongswan.org
commit e059077d3f3e307e78be7f91e5648aa5f94916a8
Author: Tobias Brunner <tobias@strongswan.org>
Date: Mon Jul 27 15:05:45 2026 +0200
eap-ttls: Merge returned auth-cfg with inner EAP method and propagate EAP-Identity
This fixes several issues with binding identities to the IKE SA.
If the client is authenticated with a certificate, the previous code still
used the client's proclaimed inner EAP-Identity when starting the EAP-TNC
method. So that method would potentially operate on an unverified
identity.
Second, if the inner EAP method overrides the client identity (the only
one is currently EAP-MSCHAPV2), the missing merge meant that the outer
IKE/EAP identity could potentially be unconfirmed.
For inner methods that don't override the identity (e.g. EAP-MD5), not
propagating the inner EAP-Identity could potentially have the same
effect.
While the implementation returned the auth-cfg of the TLS exchange
since the first referenced commit, this was mainly intended to enforce
public key constraints. So it didn't cover the phase 2 EAP methods.
For some reason EAP-PEAP did not get that method at all in that
changeset, so we'll add that in the next commit.
Fixes: 0864a31d13ff ("eap-ttls: Support EAP auth information getter in EAP-TTLS")
Fixes: 79f2102cb442 ("implemented server side support for EAP-TTLS")
Fixes: CVE-2026-78134
diff --git a/src/libcharon/plugins/eap_ttls/eap_ttls.c b/src/libcharon/plugins/eap_ttls/eap_ttls.c
index d8ad781f09..3df78bba4b 100644
--- a/src/libcharon/plugins/eap_ttls/eap_ttls.c
+++ b/src/libcharon/plugins/eap_ttls/eap_ttls.c
@@ -40,6 +40,25 @@ struct private_eap_ttls_t {
* TLS stack, wrapped by EAP helper
*/
tls_eap_t *tls_eap;
+
+ /**
+ * Role
+ */
+ bool is_server;
+
+ /**
+ * Actual server/client implementation
+ */
+ union {
+ tls_application_t *application;
+ eap_ttls_server_t *server;
+ eap_ttls_peer_t *client;
+ } impl;
+
+ /**
+ * Cached auth data for TLS and inner EAP methods
+ */
+ auth_cfg_t *auth;
};
/** Maximum number of EAP-TTLS messages/fragments allowed */
@@ -116,13 +135,31 @@ METHOD(eap_method_t, is_mutual, bool,
METHOD(eap_method_t, get_auth, auth_cfg_t*,
private_eap_ttls_t *this)
{
- return this->tls_eap->get_auth(this->tls_eap);
+ if (!this->auth)
+ {
+ auth_cfg_t *inner;
+
+ this->auth = auth_cfg_create();
+ this->auth->merge(this->auth,
+ this->tls_eap->get_auth(this->tls_eap), FALSE);
+ if (this->is_server)
+ {
+ inner = this->impl.server->get_auth(this->impl.server);
+ }
+ else
+ {
+ inner = this->impl.client->get_auth(this->impl.client);
+ }
+ this->auth->merge(this->auth, inner, FALSE);
+ }
+ return this->auth;
}
METHOD(eap_method_t, destroy, void,
private_eap_ttls_t *this)
{
this->tls_eap->destroy(this->tls_eap);
+ DESTROY_IF(this->auth);
free(this);
}
@@ -153,6 +190,10 @@ static eap_ttls_t *eap_ttls_create(identification_t *server,
.destroy = _destroy,
},
},
+ .is_server = is_server,
+ .impl = {
+ .application = application,
+ },
);
if (is_server && !lib->settings->get_bool(lib->settings,
"%s.plugins.eap-ttls.request_peer_auth", FALSE,
diff --git a/src/libcharon/plugins/eap_ttls/eap_ttls_peer.c b/src/libcharon/plugins/eap_ttls/eap_ttls_peer.c
index 63126a5c3a..f8229f5e0f 100644
--- a/src/libcharon/plugins/eap_ttls/eap_ttls_peer.c
+++ b/src/libcharon/plugins/eap_ttls/eap_ttls_peer.c
@@ -54,6 +54,11 @@ struct private_eap_ttls_peer_t {
*/
eap_method_t *method;
+ /**
+ * Auth data for phase 2 method
+ */
+ auth_cfg_t *auth;
+
/**
* Pending outbound EAP message
*/
@@ -215,6 +220,11 @@ METHOD(tls_application_t, process, status_t,
switch (status)
{
case SUCCESS:
+ if (this->method->get_auth)
+ {
+ this->auth->merge(this->auth,
+ this->method->get_auth(this->method), FALSE);
+ }
this->method->destroy(this->method);
this->method = NULL;
/* fall through to NEED_MORE */
@@ -275,11 +285,18 @@ METHOD(tls_application_t, build, status_t,
return INVALID_STATE;
}
+METHOD(eap_ttls_peer_t, get_auth, auth_cfg_t*,
+ private_eap_ttls_peer_t *this)
+{
+ return this->auth;
+}
+
METHOD(tls_application_t, destroy, void,
private_eap_ttls_peer_t *this)
{
this->server->destroy(this->server);
this->peer->destroy(this->peer);
+ this->auth->destroy(this->auth);
DESTROY_IF(this->method);
DESTROY_IF(this->out);
this->avp->destroy(this->avp);
@@ -301,10 +318,12 @@ eap_ttls_peer_t *eap_ttls_peer_create(identification_t *server,
.build = _build,
.destroy = _destroy,
},
+ .get_auth = _get_auth,
},
.server = server->clone(server),
.peer = peer->clone(peer),
.start_phase2 = TRUE,
+ .auth = auth_cfg_create(),
.avp = eap_ttls_avp_create(),
);
diff --git a/src/libcharon/plugins/eap_ttls/eap_ttls_peer.h b/src/libcharon/plugins/eap_ttls/eap_ttls_peer.h
index 0c3d90a45b..69a8435aef 100644
--- a/src/libcharon/plugins/eap_ttls/eap_ttls_peer.h
+++ b/src/libcharon/plugins/eap_ttls/eap_ttls_peer.h
@@ -37,6 +37,13 @@ struct eap_ttls_peer_t {
* Implements the TLS application data handler.
*/
tls_application_t application;
+
+ /**
+ * Get authentication details of this EAP method and its inner method(s).
+ *
+ * @return auth method, internal data
+ */
+ auth_cfg_t *(*get_auth)(eap_ttls_peer_t *this);
};
/**
diff --git a/src/libcharon/plugins/eap_ttls/eap_ttls_server.c b/src/libcharon/plugins/eap_ttls/eap_ttls_server.c
index 86f5037651..d07731009e 100644
--- a/src/libcharon/plugins/eap_ttls/eap_ttls_server.c
+++ b/src/libcharon/plugins/eap_ttls/eap_ttls_server.c
@@ -60,6 +60,11 @@ struct private_eap_ttls_server_t {
*/
eap_method_t *method;
+ /**
+ * Auth data for phase 2 method
+ */
+ auth_cfg_t *auth;
+
/**
* Pending outbound EAP message
*/
@@ -220,6 +225,10 @@ METHOD(tls_application_t, process, status_t,
if (!received_vendor && received_type == EAP_IDENTITY)
{
chunk_t eap_id;
+ bool peer_auth;
+
+ peer_auth = lib->settings->get_bool(lib->settings,
+ "%s.plugins.eap-ttls.request_peer_auth", FALSE, lib->ns);
if (this->method == NULL)
{
@@ -245,9 +254,22 @@ METHOD(tls_application_t, process, status_t,
if (this->method->get_msk(this->method, &eap_id) == SUCCESS)
{
- this->peer->destroy(this->peer);
- this->peer = identification_create_from_data(eap_id);
- DBG1(DBG_IKE, "received EAP identity '%Y'", this->peer);
+ identification_t *id;
+
+ id = identification_create_from_data(eap_id);
+ if (peer_auth && !id->equals(id, this->peer))
+ {
+ DBG1(DBG_IKE, "received tunneled EAP identity '%Y', keeping "
+ "certificate-authenticated identity '%Y'", id, this->peer);
+ id->destroy(id);
+ }
+ else
+ {
+ DBG1(DBG_IKE, "received EAP identity '%Y'", id);
+ this->auth->add(this->auth, AUTH_RULE_EAP_IDENTITY, id);
+ this->peer->destroy(this->peer);
+ this->peer = id->clone(id);
+ }
}
in->destroy(in);
@@ -255,8 +277,7 @@ METHOD(tls_application_t, process, status_t,
this->method = NULL;
/* Start Phase 2 of EAP-TTLS authentication */
- if (lib->settings->get_bool(lib->settings,
- "%s.plugins.eap-ttls.request_peer_auth", FALSE, lib->ns))
+ if (peer_auth)
{
return start_phase2_tnc(this, EAP_TLS);
}
@@ -279,6 +300,20 @@ METHOD(tls_application_t, process, status_t,
switch (status)
{
case SUCCESS:
+ if (this->method->get_auth)
+ {
+ identification_t *id;
+ auth_cfg_t *auth;
+
+ auth = this->method->get_auth(this->method);
+ id = auth->get(auth, AUTH_RULE_EAP_IDENTITY);
+ if (id)
+ {
+ this->peer->destroy(this->peer);
+ this->peer = id->clone(id);
+ }
+ this->auth->merge(this->auth, auth, FALSE);
+ }
DBG1(DBG_IKE, "%N phase2 authentication of '%Y' with %N successful",
eap_type_names, EAP_TTLS, this->peer,
eap_type_names, type);
@@ -349,11 +384,18 @@ METHOD(tls_application_t, build, status_t,
return INVALID_STATE;
}
+METHOD(eap_ttls_server_t, get_auth, auth_cfg_t*,
+ private_eap_ttls_server_t *this)
+{
+ return this->auth;
+}
+
METHOD(tls_application_t, destroy, void,
private_eap_ttls_server_t *this)
{
this->server->destroy(this->server);
this->peer->destroy(this->peer);
+ this->auth->destroy(this->auth);
DESTROY_IF(this->method);
DESTROY_IF(this->out);
this->avp->destroy(this->avp);
@@ -375,11 +417,13 @@ eap_ttls_server_t *eap_ttls_server_create(identification_t *server,
.build = _build,
.destroy = _destroy,
},
+ .get_auth = _get_auth,
},
.server = server->clone(server),
- .peer = peer->clone(peer),
+ .auth = auth_cfg_create(),
.start_phase2 = TRUE,
.start_phase2_tnc = TRUE,
+ .peer = peer->clone(peer),
.avp = eap_ttls_avp_create(),
);
diff --git a/src/libcharon/plugins/eap_ttls/eap_ttls_server.h b/src/libcharon/plugins/eap_ttls/eap_ttls_server.h
index 1e13f55c4c..3348706cf2 100644
--- a/src/libcharon/plugins/eap_ttls/eap_ttls_server.h
+++ b/src/libcharon/plugins/eap_ttls/eap_ttls_server.h
@@ -37,6 +37,13 @@ struct eap_ttls_server_t {
* Implements the TLS application data handler.
*/
tls_application_t application;
+
+ /**
+ * Get authentication details of this EAP method and its inner method(s).
+ *
+ * @return auth method, internal data
+ */
+ auth_cfg_t *(*get_auth)(eap_ttls_server_t *this);
};
/**