mem_clr.c

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/* crypto/mem_clr.c -*- mode:C; c-file-style: "eay" -*- */
/* Written by Geoff Thorpe ([email protected]) for the OpenSSL
 * project 2002.
 */
/* ====================================================================
 * Copyright (c) 2001 The OpenSSL Project.  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. 
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    the documentation and/or other materials provided with the
 *    distribution.
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 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
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 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    [email protected].
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
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 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
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 *
 * This product includes cryptographic software written by Eric Young
 * ([email protected]).  This product includes software written by Tim
 * Hudson ([email protected]).
 *
 */

#include <string.h>
#include <openssl/crypto.h>

unsigned char cleanse_ctr = 0;

void OPENSSL_cleanse(void *ptr, size_t len)
    {
    unsigned char *p = ptr;
    size_t loop = len, ctr = cleanse_ctr;
    while(loop--)
        {
        *(p++) = (unsigned char)ctr;
        ctr += (17 + ((size_t)p & 0xF));
        }
    p=memchr(ptr, (unsigned char)ctr, len);
    if(p)
        ctr += (63 + (size_t)p);
    cleanse_ctr = (unsigned char)ctr;
    }