[wpa] Add pre-shared key frontend (WPA "Personal" with just a passphrase)

Modified-by: Marty Connor <mdc@etherboot.org>
Signed-off-by: Marty Connor <mdc@etherboot.org>

src/config/general.h

@@ -69,6 +69,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
  *
  */
 #define	CRYPTO_80211_WEP	/* WEP encryption (deprecated and insecure!) */
+#define CRYPTO_80211_WPA_PSK	/* WPA "Personal" frontend using a passphrase */
 
 /*
  * Name resolution modules

src/include/gpxe/errfile.h

@@ -162,6 +162,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
 #define ERRFILE_wep			( ERRFILE_NET | 0x00240000 )
 #define ERRFILE_eapol			( ERRFILE_NET | 0x00250000 )
 #define ERRFILE_wpa			( ERRFILE_NET | 0x00260000 )
+#define ERRFILE_wpa_psk			( ERRFILE_NET | 0x00270000 )
 
 #define ERRFILE_image		      ( ERRFILE_IMAGE | 0x00000000 )
 #define ERRFILE_elf		      ( ERRFILE_IMAGE | 0x00010000 )

src/net/80211/wpa_psk.c

@@ -0,0 +1,125 @@
+/*
+ * Copyright (c) 2009 Joshua Oreman <oremanj@rwcr.net>.
+ *
+ * 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 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <gpxe/net80211.h>
+#include <gpxe/sha1.h>
+#include <gpxe/wpa.h>
+#include <errno.h>
+
+/** @file
+ *
+ * Frontend for WPA using a pre-shared key.
+ */
+
+/**
+ * Initialise WPA-PSK state
+ *
+ * @v dev	802.11 device
+ * @ret rc	Return status code
+ */
+static int wpa_psk_init ( struct net80211_device *dev )
+{
+	return wpa_make_rsn_ie ( dev, &dev->rsn_ie );
+}
+
+/**
+ * Start WPA-PSK authentication
+ *
+ * @v dev	802.11 device
+ * @ret rc	Return status code
+ */
+static int wpa_psk_start ( struct net80211_device *dev )
+{
+	char passphrase[64+1];
+	u8 pmk[WPA_PMK_LEN];
+	int len;
+	struct wpa_common_ctx *ctx = dev->handshaker->priv;
+
+	len = fetch_string_setting ( netdev_settings ( dev->netdev ),
+				     &net80211_key_setting, passphrase,
+				     64 + 1 );
+
+	if ( len <= 0 ) {
+		DBGC ( ctx, "WPA-PSK %p: no passphrase provided!\n", ctx );
+		net80211_deauthenticate ( dev, -EACCES );
+		return -EACCES;
+	}
+
+	pbkdf2_sha1 ( passphrase, len, dev->essid, strlen ( dev->essid ),
+		      4096, pmk, WPA_PMK_LEN );
+
+	DBGC ( ctx, "WPA-PSK %p: derived PMK from passphrase `%s':\n", ctx,
+	       passphrase );
+	DBGC_HD ( ctx, pmk, WPA_PMK_LEN );
+
+	return wpa_start ( dev, ctx, pmk, WPA_PMK_LEN );
+}
+
+/**
+ * Step WPA-PSK authentication
+ *
+ * @v dev	802.11 device
+ * @ret rc	Return status code
+ */
+static int wpa_psk_step ( struct net80211_device *dev )
+{
+	struct wpa_common_ctx *ctx = dev->handshaker->priv;
+
+	switch ( ctx->state ) {
+	case WPA_SUCCESS:
+		return 1;
+	case WPA_FAILURE:
+		return -EACCES;
+	default:
+		return 0;
+	}
+}
+
+/**
+ * Do-nothing function; you can't change a WPA key post-authentication
+ *
+ * @v dev	802.11 device
+ * @ret rc	Return status code
+ */
+static int wpa_psk_no_change_key ( struct net80211_device *dev __unused )
+{
+	return 0;
+}
+
+/**
+ * Disable handling of received WPA authentication frames
+ *
+ * @v dev	802.11 device
+ */
+static void wpa_psk_stop ( struct net80211_device *dev )
+{
+	wpa_stop ( dev );
+}
+
+/** WPA-PSK security handshaker */
+struct net80211_handshaker wpa_psk_handshaker __net80211_handshaker = {
+	.protocol = NET80211_SECPROT_PSK,
+	.init = wpa_psk_init,
+	.start = wpa_psk_start,
+	.step = wpa_psk_step,
+	.change_key = wpa_psk_no_change_key,
+	.stop = wpa_psk_stop,
+	.priv_len = sizeof ( struct wpa_common_ctx ),
+};