rockbox/utils/ipodpatcher/arc4.c
Dominik Riebeling c876d3bbef rbutil: Merge rbutil with utils folder.
rbutil uses several components from the utils folder, and can be
considered part of utils too. Having it in a separate folder is an
arbitrary split that doesn't help anymore these days, so merge them.

This also allows other utils to easily use libtools.make without the
need to navigate to a different folder.

Change-Id: I3fc2f4de19e3e776553efb5dea5f779dfec0dc21
2021-12-24 18:05:53 +01:00

108 lines
3.3 KiB
C

/*
* 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;
}
/*****************************************************************************/