Move airpcap_wep.c to /wsutil

svn path=/trunk/; revision=38969

5 files changed, 115 insertions, 1 deletions

diff --git a/wsutil/Makefile.common b/wsutil/Makefile.common
index 019f50bfa7..9cef17eac7 100644
--- a/wsutil/Makefile.common
+++ b/wsutil/Makefile.common
@@ -29,6 +29,7 @@
 # generated from YACC or Lex files (as Automake doesn't want them in
 # _SOURCES variables).
 LIBWSUTIL_SRC = 	\
+	airpdcap_wep.c	\
 	crc10.c		\
 	crc16.c		\
 	crc16-plain.c	\
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*/;
+}
diff --git a/wsutil/crc32.c b/wsutil/crc32.c
index eb4a9b1025..c40047dffe 100644
--- a/wsutil/crc32.c
+++ b/wsutil/crc32.c
@@ -115,7 +115,7 @@ static const guint32 crc32c_table[256] = {
  *  x^32 + x^26 + x^23 + x^22 + x^16 + x^12 + x^11 + x^8 + x^7 +
  *      x^5 + x^4 + x^2 + x + 1
  */
-static const guint32 crc32_ccitt_table[256] = {
+const guint32 crc32_ccitt_table[256] = {
         0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419,
         0x706af48f, 0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4,
         0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07,
diff --git a/wsutil/crc32.h b/wsutil/crc32.h
index 854f5fa035..514a437596 100644
--- a/wsutil/crc32.h
+++ b/wsutil/crc32.h
@@ -43,6 +43,8 @@ extern "C" {
 
 #define CRC32C(c,d) (c=(c>>8)^crc32c_table_lookup((c^(d))&0xFF))
 
+extern const guint32 crc32_ccitt_table[256];
+
 /** Lookup the crc value in the crc32c_table
  @param pos Position in the table. */
 extern guint32 crc32c_table_lookup (guchar pos);
@@ -73,6 +75,13 @@ extern guint32 crc32_ccitt(const guint8 *buf, guint len);
  @return The CRC32 CCITT checksum (using the given seed). */
 extern guint32 crc32_ccitt_seed(const guint8 *buf, guint len, guint32 seed);
 
+
+int AirPDcapWepDecrypt(
+	const guchar *seed,
+	const size_t seed_len,
+	guchar *cypher_text,
+	const size_t data_len);
+
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */
diff --git a/wsutil/libwsutil.def b/wsutil/libwsutil.def
index 0804860c2e..70ef7bb78e 100644
--- a/wsutil/libwsutil.def
+++ b/wsutil/libwsutil.def
@@ -8,6 +8,8 @@
 ; NOTE: TABS DON'T WORK IN THIS FILE, USE SPACES INSTEAD!!!
 ;
 EXPORTS
+; airpdcap.c
+AirPDcapWepDecrypt
 
 ; crc6.c
 update_crc6_by_bytes