[eap] Allow MD5-Challenge authentication method to be disabled

RFC 3748 states that implementations must support the MD5-Challenge
method.  However, some network environments may wish to disable it as
a matter of policy.

Allow support for MD5-Challenge to be controllable via the build
configuration option EAP_METHOD_MD5 in config/general.h.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/config/config_eap.c

@@ -0,0 +1,39 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ * You can also choose to distribute this program under the terms of
+ * the Unmodified Binary Distribution Licence (as given in the file
+ * COPYING.UBDL), provided that you have satisfied its requirements.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <config/general.h>
+
+/** @file
+ *
+ * EAP configuration options
+ *
+ */
+
+PROVIDE_REQUIRING_SYMBOL();
+
+/*
+ * Drag in EAP authentication methods
+ */
+#ifdef EAP_METHOD_MD5
+REQUIRE_OBJECT ( eap_md5 );
+#endif

src/config/general.h

@@ -91,6 +91,12 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 #define	CRYPTO_80211_WPA	/* WPA Personal, authenticating with passphrase */
 #define	CRYPTO_80211_WPA2	/* Add support for stronger WPA cryptography */
 
+/*
+ * 802.1x EAP authentication methods
+ *
+ */
+#define EAP_METHOD_MD5		/* MD5-Challenge port authentication */
+
 /*
  * Name resolution modules
  *