From 6e7971553e021a7fe72987490439bf9a5475fb44 Mon Sep 17 00:00:00 2001
From: Dave Chapman <dave@dchapman.com>
Date: Sat, 8 Sep 2007 23:27:49 +0000
Subject: Add functions to read and write the AUPD (flash update) image. 
 "--read-aupd aupd.bin" will read (and decrypt) the AUPD image, and
 "--write-aupd aupd.bin" will write (and encrypt) an image.  Also fix a bug in
 the "diskmove" function which corrupted the AUPD image when a bootloader was
 installed.  So in order to manipulate the aupd image, you need to restore a
 clean firmware partition, and install the bootloader with this version of
 ipodpatcher.  Decryption functions based on the description and sample code
 at http://ipodlinux.org/Flash_Decryption

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@14644 a1c6a512-1295-4272-9138-f99709370657
---
 rbutil/ipodpatcher/arc4.c | 108 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 108 insertions(+)
 create mode 100644 rbutil/ipodpatcher/arc4.c

(limited to 'rbutil/ipodpatcher/arc4.c')

diff --git a/rbutil/ipodpatcher/arc4.c b/rbutil/ipodpatcher/arc4.c
new file mode 100644
index 0000000000..75b1862b89
--- /dev/null
+++ b/rbutil/ipodpatcher/arc4.c
@@ -0,0 +1,108 @@
+/*
+ * arc4.c
+ * Release $Name: MATRIXSSL_1_8_3_OPEN $
+ *
+ * ARC4 stream cipher implementation
+ */
+/*
+ * Copyright (c) PeerSec Networks, 2002-2007. All Rights Reserved.
+ * The latest version of this code is available at http://www.matrixssl.org
+ *
+ * This software is open source; 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 General Public License does NOT permit incorporating this software 
+ * into proprietary programs.  If you are unable to comply with the GPL, a 
+ * commercial license for this software may be purchased from PeerSec Networks
+ * at http://www.peersec.com
+ * 
+ * This program is distributed in 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ * http://www.gnu.org/copyleft/gpl.html
+ */
+/******************************************************************************/
+
+#include "arc4.h"
+
+/*
+    Some accounts, such as O'Reilly's Secure Programming Cookbook say that no 
+    more than 2^30 bytes should be processed without rekeying, so we 
+    enforce that limit here.  FYI, this is equal to 1GB of data transferred.
+*/
+#define ARC4_MAX_BYTES 0x40000000
+
+/******************************************************************************/
+/*
+    SSL_RSA_WITH_RC4_* cipher callbacks
+ */
+void matrixArc4Init(struct rc4_key_t *ctx, unsigned char *key, int32_t keylen)
+{
+    unsigned char    index1, index2, tmp, *state;
+    int16_t            counter;
+
+    ctx->byteCount = 0;
+    state = &ctx->state[0];
+
+    for (counter = 0; counter < 256; counter++) {
+        state[counter] = (unsigned char)counter;
+    }
+    ctx->x = 0;
+    ctx->y = 0;
+    index1 = 0;
+    index2 = 0;
+
+    for (counter = 0; counter < 256; counter++) {
+        index2 = (key[index1] + state[counter] + index2) & 0xff;
+
+        tmp = state[counter];
+        state[counter] = state[index2];
+        state[index2] = tmp;
+
+        index1 = (index1 + 1) % keylen;
+    }
+}
+
+int32_t matrixArc4(struct rc4_key_t *ctx, unsigned char *in,
+                   unsigned char *out, int32_t len)
+{
+    unsigned char    x, y, *state, xorIndex, tmp;
+    int   counter;     /* NOTE BY DAVE CHAPMAN: This was a short in
+			  the original code, which caused a segfault
+			  when attempting to process data > 32767
+			  bytes. */
+
+    ctx->byteCount += len;
+    if (ctx->byteCount > ARC4_MAX_BYTES) {
+        return -1;
+    }
+
+    x = ctx->x;
+    y = ctx->y;
+    state = &ctx->state[0];
+    for (counter = 0; counter < len; counter++) {
+        x = (x + 1) & 0xff;
+        y = (state[x] + y) & 0xff;
+
+        tmp = state[x];
+        state[x] = state[y];
+        state[y] = tmp;
+
+        xorIndex = (state[x] + state[y]) & 0xff;
+
+        tmp = in[counter];
+        tmp ^= state[xorIndex];
+        out[counter] = tmp;
+    }
+    ctx->x = x;
+    ctx->y = y;
+    return len;
+}
+
+/*****************************************************************************/
-- 
cgit v1.2.3