133 lines
3.7 KiB
C
133 lines
3.7 KiB
C
/*
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* Copyright 2016 Dius Computing Pty Ltd. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* - Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* - Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the
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* distribution.
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* - Neither the name of the copyright holders nor the names of
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* its contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
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* THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
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* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* @author Johny Mattsson <jmattsson@dius.com.au>
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*/
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#include "mech.h"
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#include "sdk-aes.h"
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#include <string.h>
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#include <strings.h>
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/* ----- AES ---------------------------------------------------------- */
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static const struct aes_funcs
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{
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void *(*init) (const char *key, size_t keylen);
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void (*crypt) (void *ctx, const char *in, char *out);
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void (*deinit) (void *ctx);
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} aes_funcs[] =
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{
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{ aes_encrypt_init, aes_encrypt, aes_encrypt_deinit },
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{ aes_decrypt_init, aes_decrypt, aes_decrypt_deinit }
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};
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static bool do_aes (crypto_op_t *co, bool with_cbc)
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{
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const struct aes_funcs *funcs = &aes_funcs[co->op];
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void *ctx = funcs->init (co->key, co->keylen);
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if (!ctx)
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return false;
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char iv[AES_BLOCKSIZE] = { 0 };
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if (with_cbc && co->ivlen)
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memcpy (iv, co->iv, co->ivlen < AES_BLOCKSIZE ? co->ivlen : AES_BLOCKSIZE);
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const char *src = co->data;
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char *dst = co->out;
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size_t left = co->datalen;
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while (left)
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{
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char block[AES_BLOCKSIZE] = { 0 };
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size_t n = left > AES_BLOCKSIZE ? AES_BLOCKSIZE : left;
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memcpy (block, src, n);
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if (with_cbc && co->op == OP_ENCRYPT)
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{
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const char *xor = (src == co->data) ? iv : dst - AES_BLOCKSIZE;
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int i;
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for (i = 0; i < AES_BLOCKSIZE; ++i)
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block[i] ^= xor[i];
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}
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funcs->crypt (ctx, block, dst);
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if (with_cbc && co->op == OP_DECRYPT)
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{
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const char *xor = (src == co->data) ? iv : src - AES_BLOCKSIZE;
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int i;
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for (i = 0; i < AES_BLOCKSIZE; ++i)
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dst[i] ^= xor[i];
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}
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left -= n;
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src += n;
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dst += n;
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}
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funcs->deinit (ctx);
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return true;
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}
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static bool do_aes_ecb (crypto_op_t *co)
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{
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return do_aes (co, false);
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}
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static bool do_aes_cbc (crypto_op_t *co)
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{
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return do_aes (co, true);
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}
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/* ----- mechs -------------------------------------------------------- */
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static const crypto_mech_t mechs[] =
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{
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{ "AES-ECB", do_aes_ecb, AES_BLOCKSIZE },
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{ "AES-CBC", do_aes_cbc, AES_BLOCKSIZE }
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};
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const crypto_mech_t *crypto_encryption_mech (const char *name)
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{
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size_t i;
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for (i = 0; i < sizeof (mechs) / sizeof (mechs[0]); ++i)
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{
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const crypto_mech_t *mech = mechs + i;
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if (strcasecmp (name, mech->name) == 0)
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return mech;
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}
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return 0;
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}
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