Move airpcap_wep.c to /wsutil

git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@38969 f5534014-38df-0310-8fa8-9805f1628bb7

1 files changed, 102 insertions, 0 deletions

diff --git a/wsutil/airpdcap_wep.c b/wsutil/airpdcap_wep.c
new file mode 100644
index 0000000000..57b047fab7
--- /dev/null
+++ b/wsutil/airpdcap_wep.c
@@ -0,0 +1,102 @@
+/* airpcap_wep.c
+ *
+ *  $Id$
+ *
+ * Copyright (c) 2002-2005 Sam Leffler, Errno Consulting
+ * Copyright (c) 2006 CACE Technologies, Davis (California)
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * Alternatively, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2 as published by the Free
+ * Software Foundation.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+/************************************************************************/
+/*	File includes							*/
+
+#include <epan/tvbuff.h>
+#include "crc32.h"
+
+/************************************************************************/
+/* Note: copied from net80211/ieee80211_airpdcap_tkip.c			*/
+#define S_SWAP(a,b) { guint8 t = S[a]; S[a] = S[b]; S[b] = t; }
+
+/* Note: copied from FreeBSD source code, RELENG 6,			*/
+/*		sys/net80211/ieee80211_crypto_wep.c, 391		*/
+int AirPDcapWepDecrypt(
+	const guchar *seed,
+	const size_t seed_len,
+	guchar *cypher_text,
+	const size_t data_len)
+{
+	guint32 i, j, k, crc;
+	guint8 S[256];
+	guint8 icv[4];
+	size_t buflen;
+
+	/* Generate key stream (RC4 Pseudo-Random Number Generator) */
+	for (i = 0; i < 256; i++)
+		S[i] = (guint8)i;
+	for (j = i = 0; i < 256; i++) {
+		j = (j + S[i] + seed[i % seed_len]) & 0xff;
+		S_SWAP(i, j);
+	}
+
+	/* Apply RC4 to data and compute CRC32 over decrypted data */
+	crc = ~(guint32)0;
+	buflen = data_len;
+
+	for (i = j = k = 0; k < buflen; k++) {
+		i = (i + 1) & 0xff;
+		j = (j + S[i]) & 0xff;
+		S_SWAP(i, j);
+		*cypher_text ^= S[(S[i] + S[j]) & 0xff];
+		crc = crc32_ccitt_table[(crc ^ *cypher_text) & 0xff] ^ (crc >> 8);
+		cypher_text++;
+	}
+
+	crc = ~crc;
+
+	/* Encrypt little-endian CRC32 and verify that it matches with the received ICV */
+	icv[0] = (guint8)crc;
+	icv[1] = (guint8)(crc >> 8);
+	icv[2] = (guint8)(crc >> 16);
+	icv[3] = (guint8)(crc >> 24);
+	for (k = 0; k < 4; k++) {
+		i = (i + 1) & 0xff;
+		j = (j + S[i]) & 0xff;
+		S_SWAP(i, j);
+		if ((icv[k] ^ S[(S[i] + S[j]) & 0xff]) != *cypher_text++) {
+			/* ICV mismatch - drop frame */
+			return 1/*AIRPDCAP_RET_UNSUCCESS*/;
+		}
+	}
+
+	return 0/*AIRPDCAP_RET_SUCCESS*/;
+}