mirror of https://github.com/ARMmbed/mbed-os.git
Add CCM alternative implementation
Add CCM HW accelerated alternative implementationpull/6794/head
Ron Eldor
parent
b31aa03be9
commit
fdf5587e29
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/*
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* ccm_alt.c
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*
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* Copyright (C) 2018, ARM Limited, All Rights Reserved
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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*/
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#include "mbedtls/ccm.h"
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#if defined(MBEDTLS_CCM_ALT)
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#include <string.h>
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#include "mbedtls/platform.h"
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/* Implementation that should never be optimized out by the compiler */
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static void mbedtls_zeroize( void *v, size_t n ) {
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volatile unsigned char *p = (unsigned char*)v;
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while( n-- ) *p++ = 0;
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}
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#define CCM_ENCRYPT 0
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#define CCM_DECRYPT 1
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/*
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* Macros for common operations.
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* Results in smaller compiled code than static inline functions.
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*/
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/*
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* Update the CBC-MAC state in y using a block in b
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* (Always using b as the source helps the compiler optimise a bit better.)
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*/
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#define UPDATE_CBC_MAC \
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for( i = 0; i < 16; i++ ) \
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y[i] ^= b[i]; \
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\
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if( ( ret = mbedtls_cipher_update( &ctx->cipher_ctx, y, 16, y, &olen ) ) != 0 ) \
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return ( ret );
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/*
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* Encrypt or decrypt a partial block with CTR
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* Warning: using b for temporary storage! src and dst must not be b!
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* This avoids allocating one more 16 bytes buffer while allowing src == dst.
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*/
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#define CTR_CRYPT( dst, src, len ) \
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if( ( ret = mbedtls_cipher_update( &ctx->cipher_ctx, ctr, 16, b, &olen ) ) != 0 ) \
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return ( ret ); \
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\
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for( i = 0; i < len; i++ ) \
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dst[i] = src[i] ^ b[i];
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void mbedtls_ccm_init( mbedtls_ccm_context *ctx )
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{
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memset( ctx, 0, sizeof( mbedtls_ccm_context ) );
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}
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void mbedtls_ccm_free( mbedtls_ccm_context *ctx )
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{
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mbedtls_zeroize( ctx, sizeof( mbedtls_ccm_context ) );
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}
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static int mbedtls_ccm_setkey_sw( mbedtls_ccm_sw_context *ctx,
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mbedtls_cipher_id_t cipher,
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const unsigned char *key,
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unsigned int keybits )
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{
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int ret = 0;
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const mbedtls_cipher_info_t *cipher_info = NULL;
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cipher_info = mbedtls_cipher_info_from_values( cipher, keybits, MBEDTLS_MODE_ECB );
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if( cipher_info == NULL )
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return ( MBEDTLS_ERR_CCM_BAD_INPUT );
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if( cipher_info->block_size != 16 )
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return ( MBEDTLS_ERR_CCM_BAD_INPUT );
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mbedtls_cipher_free( &ctx->cipher_ctx );
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if( ( ret = mbedtls_cipher_setup( &ctx->cipher_ctx, cipher_info ) ) != 0 )
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return ( ret );
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return ( mbedtls_cipher_setkey( &ctx->cipher_ctx, key, keybits, MBEDTLS_ENCRYPT ) );
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}
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int mbedtls_ccm_setkey( mbedtls_ccm_context *ctx,
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mbedtls_cipher_id_t cipher,
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const unsigned char *key,
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unsigned int keybits )
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{
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if( ctx == NULL )
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return ( MBEDTLS_ERR_CCM_BAD_INPUT );
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if( cipher != MBEDTLS_CIPHER_ID_AES ||
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keybits != 128 )
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{
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ctx->is_sw = 1;
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return ( mbedtls_ccm_setkey_sw( &ctx->u_ctx.ccm_sw_ctx, cipher, key, keybits ) );
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}
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ctx->is_sw = 0;
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memcpy( ctx->u_ctx.ccm_alt_ctx.cipher_key , key, keybits/8 );
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ctx->u_ctx.ccm_alt_ctx.keySize_ID = CRYS_AES_Key128BitSize;
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return ( 0 );
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}
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/*
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* Authenticated encryption or decryption
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*/
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static int ccm_auth_crypt_sw( mbedtls_ccm_sw_context *ctx, int mode, size_t length,
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const unsigned char *iv, size_t iv_len,
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const unsigned char *add, size_t add_len,
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const unsigned char *input, unsigned char *output,
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unsigned char *tag, size_t tag_len )
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{
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int ret;
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unsigned char i;
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unsigned char q;
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size_t len_left, olen;
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unsigned char b[16];
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unsigned char y[16];
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unsigned char ctr[16];
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const unsigned char *src;
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unsigned char *dst;
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if( add_len > 0xFF00 )
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return ( MBEDTLS_ERR_CCM_BAD_INPUT );
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q = 16 - 1 - (unsigned char) iv_len;
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/*
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* First block B_0:
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* 0 .. 0 flags
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* 1 .. iv_len nonce (aka iv)
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* iv_len+1 .. 15 length
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*
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* With flags as (bits):
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* 7 0
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* 6 add present?
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* 5 .. 3 (t - 2) / 2
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* 2 .. 0 q - 1
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*/
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b[0] = 0;
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b[0] |= ( add_len > 0 ) << 6;
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b[0] |= ( ( tag_len - 2 ) / 2 ) << 3;
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b[0] |= q - 1;
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memcpy( b + 1, iv, iv_len );
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for( i = 0, len_left = length; i < q; i++, len_left >>= 8 )
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b[15-i] = (unsigned char)( len_left & 0xFF );
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if( len_left > 0 )
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return ( MBEDTLS_ERR_CCM_BAD_INPUT );
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/* Start CBC-MAC with first block */
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memset( y, 0, 16 );
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UPDATE_CBC_MAC;
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/*
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* If there is additional data, update CBC-MAC with
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* add_len, add, 0 (padding to a block boundary)
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*/
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if( add_len > 0 )
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{
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size_t use_len;
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len_left = add_len;
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src = add;
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memset( b, 0, 16 );
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b[0] = (unsigned char)( ( add_len >> 8 ) & 0xFF );
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b[1] = (unsigned char)( ( add_len ) & 0xFF );
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use_len = len_left < 16 - 2 ? len_left : 16 - 2;
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memcpy( b + 2, src, use_len );
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len_left -= use_len;
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src += use_len;
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UPDATE_CBC_MAC;
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while( len_left > 0 )
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{
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use_len = len_left > 16 ? 16 : len_left;
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memset( b, 0, 16 );
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memcpy( b, src, use_len );
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UPDATE_CBC_MAC;
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len_left -= use_len;
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src += use_len;
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}
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}
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/*
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* Prepare counter block for encryption:
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* 0 .. 0 flags
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* 1 .. iv_len nonce (aka iv)
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* iv_len+1 .. 15 counter (initially 1)
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*
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* With flags as (bits):
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* 7 .. 3 0
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* 2 .. 0 q - 1
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*/
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ctr[0] = q - 1;
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memcpy( ctr + 1, iv, iv_len );
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memset( ctr + 1 + iv_len, 0, q );
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ctr[15] = 1;
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/*
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* Authenticate and {en,de}crypt the message.
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*
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* The only difference between encryption and decryption is
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* the respective order of authentication and {en,de}cryption.
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*/
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len_left = length;
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src = input;
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dst = output;
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while( len_left > 0 )
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{
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size_t use_len = len_left > 16 ? 16 : len_left;
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if( mode == CCM_ENCRYPT )
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{
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memset( b, 0, 16 );
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memcpy( b, src, use_len );
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UPDATE_CBC_MAC;
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}
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CTR_CRYPT( dst, src, use_len );
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if( mode == CCM_DECRYPT )
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{
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memset( b, 0, 16 );
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memcpy( b, dst, use_len );
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UPDATE_CBC_MAC;
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}
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dst += use_len;
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src += use_len;
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len_left -= use_len;
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/*
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* Increment counter.
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* No need to check for overflow thanks to the length check above.
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*/
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for( i = 0; i < q; i++ )
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if( ++ctr[15-i] != 0 )
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break;
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}
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/*
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* Authentication: reset counter and crypt/mask internal tag
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*/
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for( i = 0; i < q; i++ )
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ctr[15-i] = 0;
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CTR_CRYPT( y, y, 16 );
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memcpy( tag, y, tag_len );
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return ( 0 );
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}
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int mbedtls_ccm_encrypt_and_tag( mbedtls_ccm_context *ctx, size_t length,
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const unsigned char *iv, size_t iv_len,
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const unsigned char *add, size_t add_len,
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const unsigned char *input, unsigned char *output,
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unsigned char *tag, size_t tag_len )
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{
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CRYSError_t CrysRet = CRYS_OK;
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/*
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* Check length requirements: SP800-38C A.1
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* Additional requirement: a < 2^16 - 2^8 to simplify the code.
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* 'length' checked later (when writing it to the first block)
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*/
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if( tag_len < 4 || tag_len > 16 || tag_len % 2 != 0 )
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return ( MBEDTLS_ERR_CCM_BAD_INPUT );
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/* Also implies q is within bounds */
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if( iv_len < 7 || iv_len > 13 )
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return ( MBEDTLS_ERR_CCM_BAD_INPUT );
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if( ctx->is_sw )
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return ( ccm_auth_crypt_sw( &ctx->u_ctx.ccm_sw_ctx, CCM_ENCRYPT, length, iv, iv_len,
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add, add_len, input, output,
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tag, tag_len ) );
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if( length > 0xFFFFFFFF || add_len > 0xFFFFFFFF )
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return ( MBEDTLS_ERR_CCM_BAD_INPUT );
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CrysRet = CRYS_AESCCM( SASI_AES_ENCRYPT, ctx->u_ctx.ccm_alt_ctx.cipher_key, ctx->u_ctx.ccm_alt_ctx.keySize_ID,
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(uint8_t*)iv, iv_len, (uint8_t*)add, add_len, (uint8_t*)input, length, output, tag_len, tag );
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if( CrysRet != CRYS_OK )
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return ( MBEDTLS_ERR_CCM_HW_ACCEL_FAILED );
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return ( 0 );
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}
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/*
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* Authenticated decryption
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*/
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static int mbedtls_ccm_auth_decrypt_sw( mbedtls_ccm_sw_context *ctx, size_t length,
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const unsigned char *iv, size_t iv_len,
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const unsigned char *add, size_t add_len,
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const unsigned char *input, unsigned char *output,
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const unsigned char *tag, size_t tag_len )
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{
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int ret;
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unsigned char check_tag[16];
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unsigned char i;
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int diff;
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if( ( ret = ccm_auth_crypt_sw( ctx, CCM_DECRYPT, length,
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iv, iv_len, add, add_len,
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input, output, check_tag, tag_len ) ) != 0 )
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{
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return ( ret );
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}
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/* Check tag in "constant-time" */
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for( diff = 0, i = 0; i < tag_len; i++ )
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diff |= tag[i] ^ check_tag[i];
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if( diff != 0 )
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{
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mbedtls_zeroize( output, length );
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return ( MBEDTLS_ERR_CCM_AUTH_FAILED );
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}
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return ( 0 );
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}
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int mbedtls_ccm_auth_decrypt( mbedtls_ccm_context *ctx, size_t length,
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const unsigned char *iv, size_t iv_len,
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const unsigned char *add, size_t add_len,
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const unsigned char *input, unsigned char *output,
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const unsigned char *tag, size_t tag_len )
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{
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CRYSError_t CrysRet = CRYS_OK;
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/*
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* Check length requirements: SP800-38C A.1
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* Additional requirement: a < 2^16 - 2^8 to simplify the code.
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* 'length' checked later (when writing it to the first block)
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*/
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if( tag_len < 4 || tag_len > 16 || tag_len % 2 != 0 )
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return ( MBEDTLS_ERR_CCM_BAD_INPUT );
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/* Also implies q is within bounds */
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if( iv_len < 7 || iv_len > 13 )
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return ( MBEDTLS_ERR_CCM_BAD_INPUT );
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if ( ctx->is_sw )
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return ( mbedtls_ccm_auth_decrypt_sw( &ctx->u_ctx.ccm_sw_ctx, length, iv, iv_len,
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add, add_len, input, output,
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tag, tag_len ) );
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if( length > 0xFFFFFFFF || add_len > 0xFFFFFFFF )
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return ( MBEDTLS_ERR_CCM_BAD_INPUT );
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CrysRet = CRYS_AESCCM( SASI_AES_DECRYPT, ctx->u_ctx.ccm_alt_ctx.cipher_key, ctx->u_ctx.ccm_alt_ctx.keySize_ID,
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(uint8_t*)iv, iv_len, (uint8_t*)add, add_len, (uint8_t*)input, length, output, tag_len, (uint8_t*)tag );
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if ( CrysRet != CRYS_OK )
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return ( MBEDTLS_ERR_CCM_HW_ACCEL_FAILED );
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return ( 0 );
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}
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#endif
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@ -0,0 +1,142 @@
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/*
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* ccm_alt.h
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*
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* Copyright (C) 2018, ARM Limited, All Rights Reserved
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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*/
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#ifndef __CCM_ALT__
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#define __CCM_ALT__
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#if defined(MBEDTLS_CCM_ALT)
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#include "crys_aesccm.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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typedef struct {
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CRYS_AESCCM_Key_t cipher_key; /*!< cipher key used */
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CRYS_AESCCM_KeySize_t keySize_ID;
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}
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mbedtls_ccm_alt_context_t;
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typedef struct {
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mbedtls_cipher_context_t cipher_ctx; /*!< cipher context used */
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}
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mbedtls_ccm_sw_context;
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typedef struct {
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union
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{
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mbedtls_ccm_alt_context_t ccm_alt_ctx;
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mbedtls_ccm_sw_context ccm_sw_ctx;
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} u_ctx;
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unsigned int is_sw;
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}
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mbedtls_ccm_context;
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/**
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* \brief Initialize CCM context (just makes references valid)
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* Makes the context ready for mbedtls_ccm_setkey() or
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* mbedtls_ccm_free().
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*
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* \param ctx CCM context to initialize
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*/
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void mbedtls_ccm_init( mbedtls_ccm_context *ctx );
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/**
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* \brief CCM initialization (encryption and decryption)
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*
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* \param ctx CCM context to be initialized
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* \param cipher cipher to use (a 128-bit block cipher)
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* \param key encryption key
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* \param keybits key size in bits (must be acceptable by the cipher)
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*
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* \return 0 if successful, or a cipher specific error code
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*/
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int mbedtls_ccm_setkey( mbedtls_ccm_context *ctx,
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mbedtls_cipher_id_t cipher,
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const unsigned char *key,
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unsigned int keybits );
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/**
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* \brief Free a CCM context and underlying cipher sub-context
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*
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* \param ctx CCM context to free
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*/
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void mbedtls_ccm_free( mbedtls_ccm_context *ctx );
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/**
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* \brief CCM buffer encryption
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*
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* \param ctx CCM context
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* \param length length of the input data in bytes
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* \param iv nonce (initialization vector)
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* \param iv_len length of IV in bytes
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* must be 2, 3, 4, 5, 6, 7 or 8
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* \param add additional data
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* \param add_len length of additional data in bytes
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* must be less than 2^16 - 2^8
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||||
* \param input buffer holding the input data
|
||||
* \param output buffer for holding the output data
|
||||
* must be at least 'length' bytes wide
|
||||
* \param tag buffer for holding the tag
|
||||
* \param tag_len length of the tag to generate in bytes
|
||||
* must be 4, 6, 8, 10, 14 or 16
|
||||
*
|
||||
* \note The tag is written to a separate buffer. To get the tag
|
||||
* concatenated with the output as in the CCM spec, use
|
||||
* tag = output + length and make sure the output buffer is
|
||||
* at least length + tag_len wide.
|
||||
*
|
||||
* \return 0 if successful
|
||||
*/
|
||||
int mbedtls_ccm_encrypt_and_tag( mbedtls_ccm_context *ctx, size_t length,
|
||||
const unsigned char *iv, size_t iv_len,
|
||||
const unsigned char *add, size_t add_len,
|
||||
const unsigned char *input, unsigned char *output,
|
||||
unsigned char *tag, size_t tag_len );
|
||||
|
||||
/**
|
||||
* \brief CCM buffer authenticated decryption
|
||||
*
|
||||
* \param ctx CCM context
|
||||
* \param length length of the input data
|
||||
* \param iv initialization vector
|
||||
* \param iv_len length of IV
|
||||
* \param add additional data
|
||||
* \param add_len length of additional data
|
||||
* \param input buffer holding the input data
|
||||
* \param output buffer for holding the output data
|
||||
* \param tag buffer holding the tag
|
||||
* \param tag_len length of the tag
|
||||
*
|
||||
* \return 0 if successful and authenticated,
|
||||
* MBEDTLS_ERR_CCM_AUTH_FAILED if tag does not match
|
||||
*/
|
||||
int mbedtls_ccm_auth_decrypt( mbedtls_ccm_context *ctx, size_t length,
|
||||
const unsigned char *iv, size_t iv_len,
|
||||
const unsigned char *add, size_t add_len,
|
||||
const unsigned char *input, unsigned char *output,
|
||||
const unsigned char *tag, size_t tag_len );
|
||||
|
||||
#ifdef __cplusplus
|
||||
}
|
||||
#endif
|
||||
|
||||
#endif /* MBEDTLS_CCM_ALT */
|
||||
#endif /* __CCM_ALT__ */
|
||||
|
|
@ -23,5 +23,8 @@
|
|||
|
||||
#define MBEDTLS_AES_ALT
|
||||
#define MBEDTLS_PLATFORM_SETUP_TEARDOWN_ALT
|
||||
#define MBEDTLS_SHA1_ALT
|
||||
#define MBEDTLS_SHA256_ALT
|
||||
#define MBEDTLS_CCM_ALT
|
||||
|
||||
#endif //__MBEDTLS_DEVICE__
|
||||
|
|
|
|||
Loading…
Reference in New Issue