mirror of
https://github.com/yuzu-emu/mbedtls.git
synced 2024-11-30 05:04:14 +01:00
530 lines
13 KiB
C
530 lines
13 KiB
C
/*
|
|
* NIST SP800-38B compliant CMAC implementation
|
|
*
|
|
* Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
|
|
* SPDX-License-Identifier: Apache-2.0
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License"); you may
|
|
* not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
|
|
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*
|
|
* This file is part of mbed TLS (https://tls.mbed.org)
|
|
*/
|
|
|
|
/*
|
|
* Definition of CMAC:
|
|
* http://csrc.nist.gov/publications/nistpubs/800-38B/SP_800-38B.pdf
|
|
* RFC 4493 "The AES-CMAC Algorithm"
|
|
*/
|
|
|
|
#if !defined(MBEDTLS_CONFIG_FILE)
|
|
#include "mbedtls/config.h"
|
|
#else
|
|
#include MBEDTLS_CONFIG_FILE
|
|
#endif
|
|
|
|
#if defined(MBEDTLS_CMAC_C)
|
|
|
|
#include "mbedtls/cmac.h"
|
|
|
|
#include <string.h>
|
|
|
|
#if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_AES_C)
|
|
#if defined(MBEDTLS_PLATFORM_C)
|
|
#include "mbedtls/platform.h"
|
|
#else
|
|
#include <stdio.h>
|
|
#define mbedtls_printf printf
|
|
#endif /* MBEDTLS_PLATFORM_C */
|
|
#endif /* MBEDTLS_SELF_TEST && MBEDTLS_AES_C */
|
|
|
|
/* Implementation that should never be optimized out by the compiler */
|
|
static void mbedtls_zeroize( void *v, size_t n ) {
|
|
volatile unsigned char *p = v; while( n-- ) *p++ = 0;
|
|
}
|
|
|
|
/*
|
|
* Initialize context
|
|
*/
|
|
void mbedtls_cmac_init( mbedtls_cmac_context *ctx )
|
|
{
|
|
memset( ctx, 0, sizeof( mbedtls_cmac_context ) );
|
|
}
|
|
|
|
/*
|
|
* Multiply by u in GF(2^128)
|
|
*
|
|
* As explained in the paper, this can be achieved as
|
|
* If MSB(p) = 0, then p = (p << 1)
|
|
* If MSB(p) = 1, then p = (p << 1) ^ Rb
|
|
* with Rb = 0x87
|
|
*
|
|
* Input and output MUST not point to the same buffer
|
|
*/
|
|
static void multiply_by_u( unsigned char *output, const unsigned char *input )
|
|
{
|
|
const unsigned char Rb = 0x87; /* block size 16 only */
|
|
unsigned char mask;
|
|
unsigned char overflow = 0;
|
|
int i;
|
|
|
|
for( i = 15; i >= 0; i-- )
|
|
{
|
|
output[i] = input[i] << 1 | overflow;
|
|
overflow = input[i] >> 7;
|
|
}
|
|
|
|
/* mask = ( input[0] >> 7 ) ? 0xff : 0x00
|
|
* using bit operations to avoid branches */
|
|
/* MSVC has a warning about unary minus on unsigned, but this is
|
|
* well-defined and precisely what we want to do here */
|
|
#if defined(_MSC_VER)
|
|
#pragma warning( push )
|
|
#pragma warning( disable : 4146 )
|
|
#endif
|
|
mask = - ( input[0] >> 7 );
|
|
#if defined(_MSC_VER)
|
|
#pragma warning( pop )
|
|
#endif
|
|
|
|
output[15] ^= Rb & mask;
|
|
}
|
|
|
|
/*
|
|
* Generate subkeys
|
|
*/
|
|
static int generate_subkeys( mbedtls_cmac_context *ctx )
|
|
{
|
|
int ret;
|
|
unsigned char L[16];
|
|
size_t olen;
|
|
|
|
/* Calculate Ek(0) */
|
|
memset( L, 0, 16 );
|
|
if( ( ret = mbedtls_cipher_update( &ctx->cipher_ctx,
|
|
L, 16, L, &olen ) ) != 0 )
|
|
{
|
|
return( ret );
|
|
}
|
|
|
|
/*
|
|
* Generate K1 and K2
|
|
*/
|
|
multiply_by_u( ctx->K1, L );
|
|
multiply_by_u( ctx->K2, ctx->K1 );
|
|
|
|
mbedtls_zeroize( L, sizeof( L ) );
|
|
|
|
return( 0 );
|
|
}
|
|
|
|
int mbedtls_cmac_setkey( mbedtls_cmac_context *ctx,
|
|
mbedtls_cipher_id_t cipher,
|
|
const unsigned char *key,
|
|
unsigned int keybits )
|
|
{
|
|
int ret;
|
|
const mbedtls_cipher_info_t *cipher_info;
|
|
|
|
cipher_info = mbedtls_cipher_info_from_values( cipher, keybits,
|
|
MBEDTLS_MODE_ECB );
|
|
if( cipher_info == NULL )
|
|
return( MBEDTLS_ERR_CMAC_BAD_INPUT );
|
|
|
|
if( cipher_info->block_size != 16 )
|
|
return( MBEDTLS_ERR_CMAC_BAD_INPUT );
|
|
|
|
mbedtls_cipher_free( &ctx->cipher_ctx );
|
|
|
|
if( ( ret = mbedtls_cipher_setup( &ctx->cipher_ctx, cipher_info ) ) != 0 )
|
|
return( ret );
|
|
|
|
if( ( ret = mbedtls_cipher_setkey( &ctx->cipher_ctx, key, keybits,
|
|
MBEDTLS_ENCRYPT ) ) != 0 )
|
|
{
|
|
return( ret );
|
|
}
|
|
|
|
return( generate_subkeys( ctx ) );
|
|
}
|
|
|
|
/*
|
|
* Free context
|
|
*/
|
|
void mbedtls_cmac_free( mbedtls_cmac_context *ctx )
|
|
{
|
|
mbedtls_cipher_free( &ctx->cipher_ctx );
|
|
mbedtls_zeroize( ctx, sizeof( mbedtls_cmac_context ) );
|
|
}
|
|
|
|
/*
|
|
* Create padded last block from (partial) last block.
|
|
*
|
|
* We can't use the padding option from the cipher layer, as it only works for
|
|
* CBC and we use ECB mode, and anyway we need to XOR K1 or K2 in addition.
|
|
*/
|
|
static void padding( unsigned char padded_block[16],
|
|
const unsigned char *last_block,
|
|
size_t length )
|
|
{
|
|
size_t j;
|
|
|
|
for( j = 0; j < 16; j++ )
|
|
{
|
|
if( j < length )
|
|
padded_block[j] = last_block[j];
|
|
else if( j == length )
|
|
padded_block[j] = 0x80;
|
|
else
|
|
padded_block[j] = 0x00;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* XOR 128-bit
|
|
* Here, macro results in smaller compiled code than static inline function
|
|
*/
|
|
#define XOR_128( o, i1, i2 ) \
|
|
for( i = 0; i < 16; i++ ) \
|
|
( o )[i] = ( i1 )[i] ^ ( i2 )[i];
|
|
|
|
/*
|
|
* Update the CMAC state using an input block x
|
|
*/
|
|
#define UPDATE_CMAC( x ) \
|
|
do { \
|
|
XOR_128( state, ( x ), state ); \
|
|
if( ( ret = mbedtls_cipher_update( &ctx->cipher_ctx, \
|
|
state, 16, state, &olen ) ) != 0 ) \
|
|
return( ret ); \
|
|
} while( 0 )
|
|
|
|
/*
|
|
* Generate tag on complete message
|
|
*/
|
|
int mbedtls_cmac_generate( mbedtls_cmac_context *ctx,
|
|
const unsigned char *input, size_t in_len,
|
|
unsigned char *tag, size_t tag_len )
|
|
|
|
{
|
|
unsigned char state[16];
|
|
unsigned char M_last[16];
|
|
int n, i, j, ret, needs_padding;
|
|
size_t olen;
|
|
|
|
/*
|
|
* Check in_len requirements: SP800-38B A
|
|
* 4 is a worst case bottom limit
|
|
*/
|
|
if( tag_len < 4 || tag_len > 16 || tag_len % 2 != 0 )
|
|
return( MBEDTLS_ERR_CMAC_BAD_INPUT );
|
|
|
|
if( in_len == 0 )
|
|
needs_padding = 1;
|
|
else
|
|
needs_padding = in_len % 16 != 0;
|
|
|
|
n = in_len / 16 + needs_padding;
|
|
|
|
/* Calculate last block */
|
|
if( needs_padding )
|
|
{
|
|
padding( M_last, input + 16 * ( n - 1 ), in_len % 16 );
|
|
XOR_128( M_last, M_last, ctx->K2 );
|
|
}
|
|
else
|
|
{
|
|
/* Last block is complete block */
|
|
XOR_128( M_last, input + 16 * ( n - 1 ), ctx->K1 );
|
|
}
|
|
|
|
memset( state, 0, 16 );
|
|
|
|
for( j = 0; j < n - 1; j++ )
|
|
UPDATE_CMAC( input + 16 * j );
|
|
|
|
UPDATE_CMAC( M_last );
|
|
|
|
memcpy( tag, state, 16 );
|
|
|
|
return( 0 );
|
|
}
|
|
|
|
#undef XOR_128
|
|
#undef UPDATE_CMAC
|
|
|
|
/*
|
|
* Authenticated decryption
|
|
*/
|
|
int mbedtls_cmac_verify( mbedtls_cmac_context *ctx,
|
|
const unsigned char *input, size_t in_len,
|
|
const unsigned char *tag, size_t tag_len )
|
|
{
|
|
int ret;
|
|
unsigned char check_tag[16];
|
|
unsigned char i;
|
|
int diff;
|
|
|
|
if( ( ret = mbedtls_cmac_generate( ctx, input, in_len,
|
|
check_tag, tag_len ) ) != 0 )
|
|
{
|
|
return ret;
|
|
}
|
|
|
|
/* Check tag in "constant-time" */
|
|
for( diff = 0, i = 0; i < tag_len; i++ )
|
|
{
|
|
diff |= tag[i] ^ check_tag[i];
|
|
}
|
|
|
|
if( diff != 0 )
|
|
{
|
|
return( MBEDTLS_ERR_CMAC_VERIFY_FAILED );
|
|
}
|
|
|
|
return( 0 );
|
|
}
|
|
|
|
int mbedtls_aes_cmac_prf_128( mbedtls_cmac_context *ctx,
|
|
const unsigned char *key, size_t key_length,
|
|
const unsigned char *input, size_t in_len,
|
|
unsigned char *tag )
|
|
{
|
|
int ret;
|
|
unsigned char zero_key[16];
|
|
unsigned char int_key[16];
|
|
|
|
if( key_length == 16 )
|
|
{
|
|
/* Use key as is */
|
|
memcpy( int_key, key, 16 );
|
|
}
|
|
else
|
|
{
|
|
mbedtls_cmac_context zero_ctx;
|
|
|
|
/* Key is AES_CMAC(0, key) */
|
|
mbedtls_cmac_init( &zero_ctx );
|
|
memset( zero_key, 0, 16 );
|
|
ret = mbedtls_cmac_setkey( &zero_ctx, MBEDTLS_CIPHER_ID_AES,
|
|
zero_key, 8 * sizeof zero_key );
|
|
if( ret != 0 )
|
|
{
|
|
return( ret );
|
|
}
|
|
ret = mbedtls_cmac_generate( &zero_ctx, key, key_length, int_key, 16 );
|
|
if( ret != 0 )
|
|
{
|
|
return( ret );
|
|
}
|
|
}
|
|
|
|
ret = mbedtls_cmac_setkey( ctx, MBEDTLS_CIPHER_ID_AES,
|
|
int_key, 8 * sizeof int_key );
|
|
if( ret != 0 )
|
|
{
|
|
return( ret );
|
|
}
|
|
|
|
mbedtls_zeroize( int_key, sizeof( int_key ) );
|
|
|
|
return( mbedtls_cmac_generate( ctx, input, in_len, tag, 16 ) );
|
|
}
|
|
|
|
#if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_AES_C)
|
|
/*
|
|
* Examples 1 to 4 from SP800-3B corrected Appendix D.1
|
|
* http://csrc.nist.gov/publications/nistpubs/800-38B/Updated_CMAC_Examples.pdf
|
|
*/
|
|
|
|
#define NB_CMAC_TESTS 4
|
|
#define NB_PRF_TESTS 3
|
|
|
|
/* Key */
|
|
static const unsigned char key[] = {
|
|
0x2b, 0x7e, 0x15, 0x16, 0x28, 0xae, 0xd2, 0xa6,
|
|
0xab, 0xf7, 0x15, 0x88, 0x09, 0xcf, 0x4f, 0x3c
|
|
};
|
|
|
|
/* Assume we don't need to test Ek0 as this is a function of the cipher */
|
|
|
|
/* Subkey K1 */
|
|
static const unsigned char K1[] = {
|
|
0xfb, 0xee, 0xd6, 0x18, 0x35, 0x71, 0x33, 0x66,
|
|
0x7c, 0x85, 0xe0, 0x8f, 0x72, 0x36, 0xa8, 0xde
|
|
};
|
|
|
|
/* Subkey K2 */
|
|
static const unsigned char K2[] = {
|
|
0xf7, 0xdd, 0xac, 0x30, 0x6a, 0xe2, 0x66, 0xcc,
|
|
0xf9, 0x0b, 0xc1, 0x1e, 0xe4, 0x6d, 0x51, 0x3b
|
|
};
|
|
|
|
/* All Messages */
|
|
static const unsigned char M[] = {
|
|
0x6b, 0xc1, 0xbe, 0xe2, 0x2e, 0x40, 0x9f, 0x96,
|
|
0xe9, 0x3d, 0x7e, 0x11, 0x73, 0x93, 0x17, 0x2a,
|
|
0xae, 0x2d, 0x8a, 0x57, 0x1e, 0x03, 0xac, 0x9c,
|
|
0x9e, 0xb7, 0x6f, 0xac, 0x45, 0xaf, 0x8e, 0x51,
|
|
0x30, 0xc8, 0x1c, 0x46, 0xa3, 0x5c, 0xe4, 0x11,
|
|
0xe5, 0xfb, 0xc1, 0x19, 0x1a, 0x0a, 0x52, 0xef,
|
|
0xf6, 0x9f, 0x24, 0x45, 0xdf, 0x4f, 0x9b, 0x17,
|
|
0xad, 0x2b, 0x41, 0x7b, 0xe6, 0x6c, 0x37, 0x10
|
|
};
|
|
|
|
static const unsigned char T[NB_CMAC_TESTS][16] = {
|
|
{
|
|
0xbb, 0x1d, 0x69, 0x29, 0xe9, 0x59, 0x37, 0x28,
|
|
0x7f, 0xa3, 0x7d, 0x12, 0x9b, 0x75, 0x67, 0x46
|
|
},
|
|
{
|
|
0x07, 0x0a, 0x16, 0xb4, 0x6b, 0x4d, 0x41, 0x44,
|
|
0xf7, 0x9b, 0xdd, 0x9d, 0xd0, 0x4a, 0x28, 0x7c
|
|
},
|
|
{
|
|
0xdf, 0xa6, 0x67, 0x47, 0xde, 0x9a, 0xe6, 0x30,
|
|
0x30, 0xca, 0x32, 0x61, 0x14, 0x97, 0xc8, 0x27
|
|
},
|
|
{
|
|
0x51, 0xf0, 0xbe, 0xbf, 0x7e, 0x3b, 0x9d, 0x92,
|
|
0xfc, 0x49, 0x74, 0x17, 0x79, 0x36, 0x3c, 0xfe
|
|
}
|
|
};
|
|
|
|
/* Sizes in bytes */
|
|
static const size_t Mlen[NB_CMAC_TESTS] = {
|
|
0,
|
|
16,
|
|
40,
|
|
64
|
|
};
|
|
|
|
/* PRF K */
|
|
static const unsigned char PRFK[] = {
|
|
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
|
|
0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
|
|
0xed, 0xcb
|
|
};
|
|
|
|
/* Sizes in bytes */
|
|
static const size_t PRFKlen[NB_PRF_TESTS] = {
|
|
18,
|
|
16,
|
|
10
|
|
};
|
|
|
|
/* PRF M */
|
|
static const unsigned char PRFM[] = {
|
|
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
|
|
0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
|
|
0x10, 0x11, 0x12, 0x13
|
|
};
|
|
|
|
static const unsigned char PRFT[NB_PRF_TESTS][16] = {
|
|
{
|
|
0x84, 0xa3, 0x48, 0xa4, 0xa4, 0x5d, 0x23, 0x5b,
|
|
0xab, 0xff, 0xfc, 0x0d, 0x2b, 0x4d, 0xa0, 0x9a
|
|
},
|
|
{
|
|
0x98, 0x0a, 0xe8, 0x7b, 0x5f, 0x4c, 0x9c, 0x52,
|
|
0x14, 0xf5, 0xb6, 0xa8, 0x45, 0x5e, 0x4c, 0x2d
|
|
},
|
|
{
|
|
0x29, 0x0d, 0x9e, 0x11, 0x2e, 0xdb, 0x09, 0xee,
|
|
0x14, 0x1f, 0xcf, 0x64, 0xc0, 0xb7, 0x2f, 0x3d
|
|
}
|
|
};
|
|
|
|
|
|
int mbedtls_cmac_self_test( int verbose )
|
|
{
|
|
mbedtls_cmac_context ctx;
|
|
unsigned char tag[16];
|
|
int i;
|
|
int ret;
|
|
|
|
mbedtls_cmac_init( &ctx );
|
|
|
|
if( mbedtls_cmac_setkey( &ctx, MBEDTLS_CIPHER_ID_AES, key, 8 * sizeof key ) != 0 )
|
|
{
|
|
if( verbose != 0 )
|
|
mbedtls_printf( " CMAC: setup failed" );
|
|
|
|
return( 1 );
|
|
}
|
|
|
|
if( ( memcmp( ctx.K1, K1, 16 ) != 0 ) ||
|
|
( memcmp( ctx.K2, K2, 16 ) != 0 ) )
|
|
{
|
|
if( verbose != 0 )
|
|
mbedtls_printf( " CMAC: subkey generation failed" );
|
|
|
|
return( 1 );
|
|
}
|
|
|
|
for( i = 0; i < NB_CMAC_TESTS; i++ )
|
|
{
|
|
mbedtls_printf( " AES-128-CMAC #%u: ", i );
|
|
|
|
ret = mbedtls_cmac_generate( &ctx, M, Mlen[i], tag, 16 );
|
|
if( ret != 0 ||
|
|
memcmp( tag, T[i], 16 ) != 0 )
|
|
{
|
|
if( verbose != 0 )
|
|
mbedtls_printf( "failed\n" );
|
|
|
|
return( 1 );
|
|
}
|
|
|
|
ret = mbedtls_cmac_verify( &ctx, M, Mlen[i], T[i], 16 );
|
|
if( ret != 0 )
|
|
{
|
|
if( verbose != 0 )
|
|
mbedtls_printf( "failed\n" );
|
|
|
|
return( 1 );
|
|
}
|
|
|
|
if( verbose != 0 )
|
|
mbedtls_printf( "passed\n" );
|
|
}
|
|
|
|
for( i = 0; i < NB_PRF_TESTS; i++ )
|
|
{
|
|
mbedtls_printf( " AES-CMAC-128-PRF #%u: ", i );
|
|
|
|
mbedtls_aes_cmac_prf_128( &ctx, PRFK, PRFKlen[i], PRFM, 20, tag );
|
|
|
|
if( ret != 0 ||
|
|
memcmp( tag, PRFT[i], 16 ) != 0 )
|
|
{
|
|
if( verbose != 0 )
|
|
mbedtls_printf( "failed\n" );
|
|
|
|
return( 1 );
|
|
}
|
|
|
|
if( verbose != 0 )
|
|
mbedtls_printf( "passed\n" );
|
|
}
|
|
|
|
mbedtls_cmac_free( &ctx );
|
|
|
|
if( verbose != 0 )
|
|
mbedtls_printf( "\n" );
|
|
|
|
return( 0 );
|
|
}
|
|
|
|
#endif /* MBEDTLS_SELF_TEST && MBEDTLS_AES_C */
|
|
|
|
#endif /* MBEDTLS_CMAC_C */
|