From 6143f926eff1685ec073e13d458734225742503f Mon Sep 17 00:00:00 2001
From: Tobias Brunner <tobias@strongswan.org>
Date: Wed, 25 Apr 2018 11:10:48 +0200
Subject: [PATCH] ike: Reject certificates that are not compliant with RFC 4945

---
 .../authenticators/pubkey_v1_authenticator.c  | 27 ++++++++++++++++-
 .../authenticators/pubkey_authenticator.c     | 29 +++++++++++++++++--
 2 files changed, 53 insertions(+), 3 deletions(-)

diff --git a/src/libcharon/sa/ikev1/authenticators/pubkey_v1_authenticator.c b/src/libcharon/sa/ikev1/authenticators/pubkey_v1_authenticator.c
index 41be15a087..9e5833efc2 100644
--- a/src/libcharon/sa/ikev1/authenticators/pubkey_v1_authenticator.c
+++ b/src/libcharon/sa/ikev1/authenticators/pubkey_v1_authenticator.c
@@ -18,6 +18,7 @@
 #include <daemon.h>
 #include <sa/ikev1/keymat_v1.h>
 #include <encoding/payloads/hash_payload.h>
+#include <credentials/certificates/x509.h>
 
 typedef struct private_pubkey_v1_authenticator_t private_pubkey_v1_authenticator_t;
 
@@ -130,6 +131,29 @@ METHOD(authenticator_t, build, status_t,
 	return status;
 }
 
+/**
+ * Check if the end-entity certificate, if any, is compliant with RFC 4945
+ */
+static bool is_compliant_cert(auth_cfg_t *auth)
+{
+	certificate_t *cert;
+	x509_t *x509;
+
+	cert = auth->get(auth, AUTH_RULE_SUBJECT_CERT);
+	if (!cert || cert->get_type(cert) != CERT_X509)
+	{
+		return TRUE;
+	}
+	x509 = (x509_t*)cert;
+	if (x509->get_flags(x509) & X509_IKE_COMPLIANT)
+	{
+		return TRUE;
+	}
+	DBG1(DBG_IKE, "rejecting certificate without digitalSignature or "
+		 "nonRepudiation keyUsage flags");
+	return FALSE;
+}
+
 METHOD(authenticator_t, process, status_t,
 	private_pubkey_v1_authenticator_t *this, message_t *message)
 {
@@ -176,7 +200,8 @@ METHOD(authenticator_t, process, status_t,
 														id, auth, TRUE);
 	while (enumerator->enumerate(enumerator, &public, &current_auth))
 	{
-		if (public->verify(public, scheme, NULL, hash, sig))
+		if (public->verify(public, scheme, NULL, hash, sig) &&
+			is_compliant_cert(current_auth))
 		{
 			DBG1(DBG_IKE, "authentication of '%Y' with %N successful",
 				 id, signature_scheme_names, scheme);
diff --git a/src/libcharon/sa/ikev2/authenticators/pubkey_authenticator.c b/src/libcharon/sa/ikev2/authenticators/pubkey_authenticator.c
index c6c4829102..652b837fe3 100644
--- a/src/libcharon/sa/ikev2/authenticators/pubkey_authenticator.c
+++ b/src/libcharon/sa/ikev2/authenticators/pubkey_authenticator.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2008-2017 Tobias Brunner
+ * Copyright (C) 2008-2018 Tobias Brunner
  * Copyright (C) 2005-2009 Martin Willi
  * Copyright (C) 2005 Jan Hutter
  * HSR Hochschule fuer Technik Rapperswil
@@ -23,6 +23,7 @@
 #include <asn1/asn1.h>
 #include <asn1/oid.h>
 #include <collections/array.h>
+#include <credentials/certificates/x509.h>
 
 typedef struct private_pubkey_authenticator_t private_pubkey_authenticator_t;
 
@@ -414,6 +415,29 @@ METHOD(authenticator_t, build, status_t,
 	return status;
 }
 
+/**
+ * Check if the end-entity certificate, if any, is compliant with RFC 4945
+ */
+static bool is_compliant_cert(auth_cfg_t *auth)
+{
+	certificate_t *cert;
+	x509_t *x509;
+
+	cert = auth->get(auth, AUTH_RULE_SUBJECT_CERT);
+	if (!cert || cert->get_type(cert) != CERT_X509)
+	{
+		return TRUE;
+	}
+	x509 = (x509_t*)cert;
+	if (x509->get_flags(x509) & X509_IKE_COMPLIANT)
+	{
+		return TRUE;
+	}
+	DBG1(DBG_IKE, "rejecting certificate without digitalSignature or "
+		 "nonRepudiation keyUsage flags");
+	return FALSE;
+}
+
 METHOD(authenticator_t, process, status_t,
 	private_pubkey_authenticator_t *this, message_t *message)
 {
@@ -479,7 +503,8 @@ METHOD(authenticator_t, process, status_t,
 	while (enumerator->enumerate(enumerator, &public, &current_auth))
 	{
 		if (public->verify(public, params->scheme, params->params, octets,
-						   auth_data))
+						   auth_data) &&
+			is_compliant_cert(current_auth))
 		{
 			if (auth_method != AUTH_DS)
 			{
-- 
2.47.2