109 lines
3.3 KiB
C
109 lines
3.3 KiB
C
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/*
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* arc4.c
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* Release $Name: MATRIXSSL_1_8_3_OPEN $
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*
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* ARC4 stream cipher implementation
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*/
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/*
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* Copyright (c) PeerSec Networks, 2002-2007. All Rights Reserved.
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* The latest version of this code is available at http://www.matrixssl.org
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*
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* This software is open source; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This General Public License does NOT permit incorporating this software
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* into proprietary programs. If you are unable to comply with the GPL, a
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* commercial license for this software may be purchased from PeerSec Networks
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* at http://www.peersec.com
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*
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* This program is distributed in WITHOUT ANY WARRANTY; without even the
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* implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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* See the GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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* http://www.gnu.org/copyleft/gpl.html
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*/
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/******************************************************************************/
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#include "arc4.h"
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/*
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Some accounts, such as O'Reilly's Secure Programming Cookbook say that no
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more than 2^30 bytes should be processed without rekeying, so we
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enforce that limit here. FYI, this is equal to 1GB of data transferred.
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*/
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#define ARC4_MAX_BYTES 0x40000000
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/******************************************************************************/
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/*
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SSL_RSA_WITH_RC4_* cipher callbacks
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*/
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void matrixArc4Init(struct rc4_key_t *ctx, unsigned char *key, int32_t keylen)
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{
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unsigned char index1, index2, tmp, *state;
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int16_t counter;
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ctx->byteCount = 0;
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state = &ctx->state[0];
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for (counter = 0; counter < 256; counter++) {
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state[counter] = (unsigned char)counter;
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}
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ctx->x = 0;
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ctx->y = 0;
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index1 = 0;
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index2 = 0;
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for (counter = 0; counter < 256; counter++) {
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index2 = (key[index1] + state[counter] + index2) & 0xff;
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tmp = state[counter];
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state[counter] = state[index2];
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state[index2] = tmp;
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index1 = (index1 + 1) % keylen;
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}
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}
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int32_t matrixArc4(struct rc4_key_t *ctx, unsigned char *in,
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unsigned char *out, int32_t len)
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{
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unsigned char x, y, *state, xorIndex, tmp;
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int counter; /* NOTE BY DAVE CHAPMAN: This was a short in
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the original code, which caused a segfault
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when attempting to process data > 32767
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bytes. */
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ctx->byteCount += len;
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if (ctx->byteCount > ARC4_MAX_BYTES) {
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return -1;
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}
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x = ctx->x;
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y = ctx->y;
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state = &ctx->state[0];
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for (counter = 0; counter < len; counter++) {
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x = (x + 1) & 0xff;
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y = (state[x] + y) & 0xff;
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tmp = state[x];
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state[x] = state[y];
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state[y] = tmp;
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xorIndex = (state[x] + state[y]) & 0xff;
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tmp = in[counter];
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tmp ^= state[xorIndex];
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out[counter] = tmp;
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}
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ctx->x = x;
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ctx->y = y;
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return len;
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}
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/*****************************************************************************/
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