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/*
* Copyright (c) 1997 - 2008 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* 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.
*
* 2. 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.
*
* 3. Neither the name of the Institute 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 INSTITUTE 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 INSTITUTE 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.
*/
#include "krb5_locl.h"
void
_krb5_evp_schedule(krb5_context context,
struct _krb5_key_type *kt,
struct _krb5_key_data *kd)
{
struct _krb5_evp_schedule *key = kd->schedule->data;
const EVP_CIPHER *c = (*kt->evp)();
EVP_CIPHER_CTX_init(&key->ectx);
EVP_CIPHER_CTX_init(&key->dctx);
EVP_CipherInit_ex(&key->ectx, c, NULL, kd->key->keyvalue.data, NULL, 1);
EVP_CipherInit_ex(&key->dctx, c, NULL, kd->key->keyvalue.data, NULL, 0);
}
void
_krb5_evp_cleanup(krb5_context context, struct _krb5_key_data *kd)
{
struct _krb5_evp_schedule *key = kd->schedule->data;
EVP_CIPHER_CTX_cleanup(&key->ectx);
EVP_CIPHER_CTX_cleanup(&key->dctx);
}
krb5_error_code
_krb5_evp_encrypt(krb5_context context,
struct _krb5_key_data *key,
void *data,
size_t len,
krb5_boolean encryptp,
int usage,
void *ivec)
{
struct _krb5_evp_schedule *ctx = key->schedule->data;
EVP_CIPHER_CTX *c;
c = encryptp ? &ctx->ectx : &ctx->dctx;
if (ivec == NULL) {
/* alloca ? */
size_t len2 = EVP_CIPHER_CTX_iv_length(c);
void *loiv = malloc(len2);
if (loiv == NULL) {
krb5_clear_error_message(context);
return ENOMEM;
}
memset(loiv, 0, len2);
EVP_CipherInit_ex(c, NULL, NULL, NULL, loiv, -1);
free(loiv);
} else
EVP_CipherInit_ex(c, NULL, NULL, NULL, ivec, -1);
EVP_Cipher(c, data, data, len);
return 0;
}
static const unsigned char zero_ivec[EVP_MAX_BLOCK_LENGTH] = { 0 };
krb5_error_code
_krb5_evp_encrypt_cts(krb5_context context,
struct _krb5_key_data *key,
void *data,
size_t len,
krb5_boolean encryptp,
int usage,
void *ivec)
{
size_t i, blocksize;
struct _krb5_evp_schedule *ctx = key->schedule->data;
unsigned char tmp[EVP_MAX_BLOCK_LENGTH], ivec2[EVP_MAX_BLOCK_LENGTH];
EVP_CIPHER_CTX *c;
unsigned char *p;
c = encryptp ? &ctx->ectx : &ctx->dctx;
blocksize = EVP_CIPHER_CTX_block_size(c);
if (len < blocksize) {
krb5_set_error_message(context, EINVAL,
"message block too short");
return EINVAL;
} else if (len == blocksize) {
EVP_CipherInit_ex(c, NULL, NULL, NULL, zero_ivec, -1);
EVP_Cipher(c, data, data, len);
return 0;
}
if (ivec)
EVP_CipherInit_ex(c, NULL, NULL, NULL, ivec, -1);
else
EVP_CipherInit_ex(c, NULL, NULL, NULL, zero_ivec, -1);
if (encryptp) {
p = data;
i = ((len - 1) / blocksize) * blocksize;
EVP_Cipher(c, p, p, i);
p += i - blocksize;
len -= i;
memcpy(ivec2, p, blocksize);
for (i = 0; i < len; i++)
tmp[i] = p[i + blocksize] ^ ivec2[i];
for (; i < blocksize; i++)
tmp[i] = 0 ^ ivec2[i];
EVP_CipherInit_ex(c, NULL, NULL, NULL, zero_ivec, -1);
EVP_Cipher(c, p, tmp, blocksize);
memcpy(p + blocksize, ivec2, len);
if (ivec)
memcpy(ivec, p, blocksize);
} else {
unsigned char tmp2[EVP_MAX_BLOCK_LENGTH], tmp3[EVP_MAX_BLOCK_LENGTH];
p = data;
if (len > blocksize * 2) {
/* remove last two blocks and round up, decrypt this with cbc, then do cts dance */
i = ((((len - blocksize * 2) + blocksize - 1) / blocksize) * blocksize);
memcpy(ivec2, p + i - blocksize, blocksize);
EVP_Cipher(c, p, p, i);
p += i;
len -= i + blocksize;
} else {
if (ivec)
memcpy(ivec2, ivec, blocksize);
else
memcpy(ivec2, zero_ivec, blocksize);
len -= blocksize;
}
memcpy(tmp, p, blocksize);
EVP_CipherInit_ex(c, NULL, NULL, NULL, zero_ivec, -1);
EVP_Cipher(c, tmp2, p, blocksize);
memcpy(tmp3, p + blocksize, len);
memcpy(tmp3 + len, tmp2 + len, blocksize - len); /* xor 0 */
for (i = 0; i < len; i++)
p[i + blocksize] = tmp2[i] ^ tmp3[i];
EVP_CipherInit_ex(c, NULL, NULL, NULL, zero_ivec, -1);
EVP_Cipher(c, p, tmp3, blocksize);
for (i = 0; i < blocksize; i++)
p[i] ^= ivec2[i];
if (ivec)
memcpy(ivec, tmp, blocksize);
}
return 0;
}
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