net-misc/strongswan/files/strongswan-5.0.2-lenient-encryption.patch

Even in Main Mode, some Sonicwall boxes seem to send ID/HASH payloads in
unencrypted form, probably to allow PSK lookup based on the ID payloads. We
by default reject that, but accept it if the
charon.accept_unencrypted_mainmode_messages option is set in strongswan.conf.

Initial patch courtesy of Paul Stewart.

diff -ru strongswan-5.0.2-orig/src/libcharon/encoding/message.c strongswan-5.0.2/src/libcharon/encoding/message.c
--- strongswan-5.0.2-orig/src/libcharon/encoding/message.c	2014-04-17 10:43:46.814017374 -0700
+++ strongswan-5.0.2/src/libcharon/encoding/message.c	2014-04-17 11:00:05.237621496 -0700
@@ -1816,6 +1816,24 @@
 	return SUCCESS;
 }
 
+ /**
+ * Do we accept unencrypted ID/HASH payloads in Main Mode, as seen from
+ * some SonicWall boxes?
+ */
+static bool accept_unencrypted_mm(private_message_t *this, payload_type_t type)
+{
+	if (this->exchange_type == ID_PROT)
+	{
+		if (type == ID_V1 || type == HASH_V1)
+		{
+			return lib->settings->get_bool(lib->settings,
+									"charon.accept_unencrypted_mainmode_messages",
+									FALSE);
+		}
+	}
+	return FALSE;
+}
+
 /**
  * Decrypt payload from the encryption payload
  */
@@ -1935,7 +1953,8 @@
 			this->exchange_type != AGGRESSIVE)
 		{
 			rule = get_payload_rule(this, type);
-			if (!rule || rule->encrypted)
+			if (!rule || rule->encrypted &&
+				!accept_unencrypted_mm(this, type))
 			{
 				DBG1(DBG_ENC, "payload type %N was not encrypted",
 					 payload_type_names, type);