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