mbedtls/library/ccm.c
Mateusz Starzyk ca9dc8d1d7 Rename ccm_calculate_first_block function.
Signed-off-by: Mateusz Starzyk <mateusz.starzyk@mobica.com>
2021-08-10 13:56:37 +02:00

695 lines
21 KiB
C

/*
* NIST SP800-38C compliant CCM implementation
*
* Copyright The Mbed TLS Contributors
* 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.
*/
/*
* Definition of CCM:
* http://csrc.nist.gov/publications/nistpubs/800-38C/SP800-38C_updated-July20_2007.pdf
* RFC 3610 "Counter with CBC-MAC (CCM)"
*
* Related:
* RFC 5116 "An Interface and Algorithms for Authenticated Encryption"
*/
#include "common.h"
#if defined(MBEDTLS_CCM_C)
#include "mbedtls/ccm.h"
#include "mbedtls/platform_util.h"
#include "mbedtls/error.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 */
#if !defined(MBEDTLS_CCM_ALT)
#define CCM_VALIDATE_RET( cond ) \
MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_CCM_BAD_INPUT )
#define CCM_VALIDATE( cond ) \
MBEDTLS_INTERNAL_VALIDATE( cond )
/*
* Initialize context
*/
void mbedtls_ccm_init( mbedtls_ccm_context *ctx )
{
CCM_VALIDATE( ctx != NULL );
memset( ctx, 0, sizeof( mbedtls_ccm_context ) );
}
int mbedtls_ccm_setkey( mbedtls_ccm_context *ctx,
mbedtls_cipher_id_t cipher,
const unsigned char *key,
unsigned int keybits )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
const mbedtls_cipher_info_t *cipher_info;
CCM_VALIDATE_RET( ctx != NULL );
CCM_VALIDATE_RET( key != NULL );
cipher_info = mbedtls_cipher_info_from_values( cipher, keybits,
MBEDTLS_MODE_ECB );
if( cipher_info == NULL )
return( MBEDTLS_ERR_CCM_BAD_INPUT );
if( cipher_info->block_size != 16 )
return( MBEDTLS_ERR_CCM_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( 0 );
}
/*
* Free context
*/
void mbedtls_ccm_free( mbedtls_ccm_context *ctx )
{
if( ctx == NULL )
return;
mbedtls_cipher_free( &ctx->cipher_ctx );
mbedtls_platform_zeroize( ctx, sizeof( mbedtls_ccm_context ) );
}
#define CCM_STATE__CLEAR 0
#define CCM_STATE__STARTED (1 << 0)
#define CCM_STATE__LENGHTS_SET (1 << 1)
#define CCM_STATE__ERROR (1 << 2)
/*
* Encrypt or decrypt a partial block with CTR
*/
static int mbedtls_ccm_crypt( mbedtls_ccm_context *ctx,
size_t offset, size_t use_len,
const unsigned char *input,
unsigned char *output )
{
size_t i;
size_t olen = 0;
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
unsigned char tmp_buf[16] = {0};
if( ( ret = mbedtls_cipher_update( &ctx->cipher_ctx, ctx->ctr, 16, tmp_buf,
&olen ) ) != 0 )
{
ctx->state |= CCM_STATE__ERROR;
mbedtls_platform_zeroize(tmp_buf, sizeof(tmp_buf));
return ret;
}
for( i = 0; i < use_len; i++ )
output[i] = input[i] ^ tmp_buf[offset + i];
mbedtls_platform_zeroize(tmp_buf, sizeof(tmp_buf));
return ret;
}
static void mbedtls_ccm_clear_state(mbedtls_ccm_context *ctx) {
ctx->state = CCM_STATE__CLEAR;
memset( ctx->y, 0, 16);
memset( ctx->ctr, 0, 16);
}
static int ccm_calculate_first_block_if_ready(mbedtls_ccm_context *ctx)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
unsigned char i;
size_t len_left, olen;
/* length calulcation can be done only after both
* mbedtls_ccm_starts() and mbedtls_ccm_set_lengths() have been executed
*/
if( !(ctx->state & CCM_STATE__STARTED) || !(ctx->state & CCM_STATE__LENGHTS_SET) )
return 0;
if( ctx->tag_len == 0 && \
( ctx->mode == MBEDTLS_CCM_ENCRYPT || ctx->mode == MBEDTLS_CCM_DECRYPT ) )
return( MBEDTLS_ERR_CCM_BAD_INPUT );
/*
* First block:
* 0 .. 0 flags
* 1 .. iv_len nonce (aka iv) - set by: mbedtls_ccm_starts()
* iv_len+1 .. 15 length
*
* With flags as (bits):
* 7 0
* 6 add present?
* 5 .. 3 (t - 2) / 2
* 2 .. 0 q - 1
*/
ctx->y[0] |= ( ctx->add_len > 0 ) << 6;
ctx->y[0] |= ( ( ctx->tag_len - 2 ) / 2 ) << 3;
ctx->y[0] |= ctx->q - 1;
for( i = 0, len_left = ctx->plaintext_len; i < ctx->q; i++, len_left >>= 8 )
ctx->y[15-i] = (unsigned char)( len_left & 0xFF );
if( len_left > 0 )
{
ctx->state |= CCM_STATE__ERROR;
return( MBEDTLS_ERR_CCM_BAD_INPUT );
}
/* Start CBC-MAC with first block*/
if( ( ret = mbedtls_cipher_update( &ctx->cipher_ctx, ctx->y, 16, ctx->y, &olen ) ) != 0 )
{
ctx->state |= CCM_STATE__ERROR;
return( ret );
}
return (0);
}
int mbedtls_ccm_starts( mbedtls_ccm_context *ctx,
int mode,
const unsigned char *iv,
size_t iv_len )
{
CCM_VALIDATE_RET( ctx != NULL );
CCM_VALIDATE_RET( iv != NULL );
CCM_VALIDATE_RET( mode == MBEDTLS_CCM_DECRYPT || \
mode == MBEDTLS_CCM_STAR_DECRYPT || \
mode == MBEDTLS_CCM_ENCRYPT || \
mode == MBEDTLS_CCM_STAR_ENCRYPT );
/* Also implies q is within bounds */
if( iv_len < 7 || iv_len > 13 )
return( MBEDTLS_ERR_CCM_BAD_INPUT );
if( ctx->state & CCM_STATE__ERROR )
{
mbedtls_ccm_clear_state(ctx);
}
ctx->mode = mode;
ctx->q = 16 - 1 - (unsigned char) iv_len;
/*
* Prepare counter block for encryption:
* 0 .. 0 flags
* 1 .. iv_len nonce (aka iv)
* iv_len+1 .. 15 counter (initially 1)
*
* With flags as (bits):
* 7 .. 3 0
* 2 .. 0 q - 1
*/
memset( ctx->ctr, 0, 16);
ctx->ctr[0] = ctx->q - 1;
memcpy( ctx->ctr + 1, iv, iv_len );
memset( ctx->ctr + 1 + iv_len, 0, ctx->q );
ctx->ctr[15] = 1;
/*
* See ccm_calculate_first_block_if_ready() for block layout description
*/
memcpy( ctx->y + 1, iv, iv_len );
ctx->state |= CCM_STATE__STARTED;
return ccm_calculate_first_block_if_ready(ctx);
}
int mbedtls_ccm_set_lengths( mbedtls_ccm_context *ctx,
size_t total_ad_len,
size_t plaintext_len,
size_t tag_len )
{
CCM_VALIDATE_RET( ctx != NULL );
/*
* Check length requirements: SP800-38C A.1
* Additional requirement: a < 2^16 - 2^8 to simplify the code.
* 'length' checked later (when writing it to the first block)
*
* Also, loosen the requirements to enable support for CCM* (IEEE 802.15.4).
*/
if( tag_len == 2 || tag_len > 16 || tag_len % 2 != 0 )
return( MBEDTLS_ERR_CCM_BAD_INPUT );
if( total_ad_len >= 0xFF00 )
return( MBEDTLS_ERR_CCM_BAD_INPUT );
if( ctx->state & CCM_STATE__ERROR )
{
mbedtls_ccm_clear_state(ctx);
}
ctx->plaintext_len = plaintext_len;
ctx->add_len = total_ad_len;
ctx->tag_len = tag_len;
ctx->processed = 0;
ctx->state |= CCM_STATE__LENGHTS_SET;
return ccm_calculate_first_block_if_ready(ctx);
}
int mbedtls_ccm_update_ad( mbedtls_ccm_context *ctx,
const unsigned char *add,
size_t add_len )
{
CCM_VALIDATE_RET( ctx->add_len == 0 || add != NULL );
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
unsigned char i;
size_t olen, use_len, offset;
if( ctx->add_len > 0 && add_len > 0)
{
if( ctx->processed == 0 )
{
ctx->y[0] ^= (unsigned char)( ( ctx->add_len >> 8 ) & 0xFF );
ctx->y[1] ^= (unsigned char)( ( ctx->add_len ) & 0xFF );
ctx->processed += 2;
}
while( add_len > 0 )
{
offset = ctx->processed % 16;
use_len = 16 - offset;
if( use_len > add_len )
use_len = add_len;
for( i = 0; i < use_len; i++ )
ctx->y[i + offset] ^= add[i];
ctx->processed += use_len;
add_len -= use_len;
add += use_len;
if( use_len + offset == 16 || ctx->processed - 2 == ctx->add_len )
{
if( ( ret = mbedtls_cipher_update( &ctx->cipher_ctx, ctx->y, 16, ctx->y, &olen ) ) != 0 )
{
ctx->state |= CCM_STATE__ERROR;
return( ret );
}
}
}
}
if( ctx->processed - 2 == ctx->add_len )
ctx->processed = 0; // prepare for mbedtls_ccm_update()
return (0);
}
int mbedtls_ccm_update( mbedtls_ccm_context *ctx,
const unsigned char *input, size_t input_len,
unsigned char *output, size_t output_size,
size_t *output_len )
{
CCM_VALIDATE_RET( ctx->plaintext_len == 0 || input != NULL );
CCM_VALIDATE_RET( ctx->plaintext_len == 0 || output != NULL );
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
unsigned char i;
size_t use_len, offset, olen;
if( output_size < input_len )
return( MBEDTLS_ERR_CCM_BAD_INPUT );
CCM_VALIDATE_RET( output_length != NULL );
*output_len = input_len;
while ( input_len > 0 )
{
offset = ctx->processed % 16;
use_len = 16 - offset;
if( use_len > input_len )
use_len = input_len;
ctx->processed += use_len;
if( ctx->mode == MBEDTLS_CCM_ENCRYPT || \
ctx->mode == MBEDTLS_CCM_STAR_ENCRYPT )
{
for( i = 0; i < use_len; i++ )
ctx->y[i + offset] ^= input[i];
if( use_len + offset == 16 || ctx->processed == ctx->plaintext_len )
{
if( ( ret = mbedtls_cipher_update( &ctx->cipher_ctx, ctx->y, 16, ctx->y, &olen ) ) != 0 )
{
ctx->state |= CCM_STATE__ERROR;
return( ret );
}
}
ret = mbedtls_ccm_crypt( ctx, offset, use_len, input, output );
if( ret != 0 )
return ret;
}
if( ctx->mode == MBEDTLS_CCM_DECRYPT || \
ctx->mode == MBEDTLS_CCM_STAR_DECRYPT )
{
ret = mbedtls_ccm_crypt( ctx, offset, use_len, input, output );
if( ret != 0 )
return ret;
for( i = 0; i < use_len; i++ )
ctx->y[i + offset] ^= output[i];
if( use_len + offset == 16 || ctx->processed == ctx->plaintext_len )
{
if( ( ret = mbedtls_cipher_update( &ctx->cipher_ctx, ctx->y, 16, ctx->y, &olen ) ) != 0 )
{
ctx->state |= CCM_STATE__ERROR;
return( ret );
}
}
}
if( use_len + offset == 16 || ctx->processed == ctx->plaintext_len )
{
for( i = 0; i < ctx->q; i++ )
if( ++(ctx->ctr)[15-i] != 0 )
break;
}
input_len -= use_len;
input += use_len;
output += use_len;
}
return 0;
}
int mbedtls_ccm_finish( mbedtls_ccm_context *ctx,
unsigned char *tag, size_t tag_len )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
unsigned char i;
CCM_VALIDATE_RET( tag_len == 0 || tag != NULL );
/*
* Authentication: reset counter and crypt/mask internal tag
*/
for( i = 0; i < ctx->q; i++ )
ctx->ctr[15-i] = 0;
ret = mbedtls_ccm_crypt( ctx, 0, 16, ctx->y, ctx->y );
if( ret != 0 )
return ret;
memcpy( tag, ctx->y, tag_len );
mbedtls_ccm_clear_state(ctx);
return( 0 );
}
/*
* Authenticated encryption or decryption
*/
static int ccm_auth_crypt( mbedtls_ccm_context *ctx, int mode, 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 )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
size_t olen;
if( ( ret = mbedtls_ccm_starts( ctx, mode, iv, iv_len ) ) != 0 )
return( ret );
if( ( ret = mbedtls_ccm_set_lengths( ctx, add_len, length, tag_len ) ) != 0 )
return( ret );
if( ( ret = mbedtls_ccm_update_ad( ctx, add, add_len ) ) != 0 )
return( ret );
if( ( ret = mbedtls_ccm_update( ctx, input, length,
output, length, &olen ) ) != 0 )
return( ret );
if( ( ret = mbedtls_ccm_finish( ctx, tag, tag_len ) ) != 0 )
return( ret );
return( 0 );
}
/*
* Authenticated encryption
*/
int mbedtls_ccm_star_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 )
{
return( ccm_auth_crypt( ctx, MBEDTLS_CCM_STAR_ENCRYPT, length, iv, iv_len,
add, add_len, input, output, tag, tag_len ) );
}
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 )
{
return( ccm_auth_crypt( ctx, MBEDTLS_CCM_ENCRYPT, length, iv, iv_len,
add, add_len, input, output, tag, tag_len ) );
}
static int mbedtls_ccm_compare_tags(const unsigned char *tag1, const unsigned char *tag2, size_t tag_len)
{
unsigned char i;
int diff;
/* Check tag in "constant-time" */
for( diff = 0, i = 0; i < tag_len; i++ )
diff |= tag1[i] ^ tag2[i];
if( diff != 0 )
{
return( MBEDTLS_ERR_CCM_AUTH_FAILED );
}
return( 0 );
}
/*
* Authenticated decryption
*/
int mbedtls_ccm_star_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 )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
unsigned char check_tag[16];
if( ( ret = ccm_auth_crypt( ctx, MBEDTLS_CCM_STAR_DECRYPT, length,
iv, iv_len, add, add_len,
input, output, check_tag, tag_len ) ) != 0 )
{
return( ret );
}
if( ( ret = mbedtls_ccm_compare_tags( tag, check_tag, tag_len ) ) != 0 )
{
mbedtls_platform_zeroize( output, length );
return( ret );
}
return( 0 );
}
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 )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
unsigned char check_tag[16];
if( ( ret = ccm_auth_crypt( ctx, MBEDTLS_CCM_DECRYPT, length,
iv, iv_len, add, add_len,
input, output, check_tag, tag_len ) ) != 0 )
{
return( ret );
}
if( ( ret = mbedtls_ccm_compare_tags( tag, check_tag, tag_len ) ) != 0 )
{
mbedtls_platform_zeroize( output, length );
return( ret );
}
return( 0 );
}
#endif /* !MBEDTLS_CCM_ALT */
#if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_AES_C)
/*
* Examples 1 to 3 from SP800-38C Appendix C
*/
#define NB_TESTS 3
#define CCM_SELFTEST_PT_MAX_LEN 24
#define CCM_SELFTEST_CT_MAX_LEN 32
/*
* The data is the same for all tests, only the used length changes
*/
static const unsigned char key_test_data[] = {
0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,
0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f
};
static const unsigned char iv_test_data[] = {
0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
0x18, 0x19, 0x1a, 0x1b
};
static const unsigned char ad_test_data[] = {
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
0x10, 0x11, 0x12, 0x13
};
static const unsigned char msg_test_data[CCM_SELFTEST_PT_MAX_LEN] = {
0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,
0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
};
static const size_t iv_len_test_data [NB_TESTS] = { 7, 8, 12 };
static const size_t add_len_test_data[NB_TESTS] = { 8, 16, 20 };
static const size_t msg_len_test_data[NB_TESTS] = { 4, 16, 24 };
static const size_t tag_len_test_data[NB_TESTS] = { 4, 6, 8 };
static const unsigned char res_test_data[NB_TESTS][CCM_SELFTEST_CT_MAX_LEN] = {
{ 0x71, 0x62, 0x01, 0x5b, 0x4d, 0xac, 0x25, 0x5d },
{ 0xd2, 0xa1, 0xf0, 0xe0, 0x51, 0xea, 0x5f, 0x62,
0x08, 0x1a, 0x77, 0x92, 0x07, 0x3d, 0x59, 0x3d,
0x1f, 0xc6, 0x4f, 0xbf, 0xac, 0xcd },
{ 0xe3, 0xb2, 0x01, 0xa9, 0xf5, 0xb7, 0x1a, 0x7a,
0x9b, 0x1c, 0xea, 0xec, 0xcd, 0x97, 0xe7, 0x0b,
0x61, 0x76, 0xaa, 0xd9, 0xa4, 0x42, 0x8a, 0xa5,
0x48, 0x43, 0x92, 0xfb, 0xc1, 0xb0, 0x99, 0x51 }
};
int mbedtls_ccm_self_test( int verbose )
{
mbedtls_ccm_context ctx;
/*
* Some hardware accelerators require the input and output buffers
* would be in RAM, because the flash is not accessible.
* Use buffers on the stack to hold the test vectors data.
*/
unsigned char plaintext[CCM_SELFTEST_PT_MAX_LEN];
unsigned char ciphertext[CCM_SELFTEST_CT_MAX_LEN];
size_t i;
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
mbedtls_ccm_init( &ctx );
if( mbedtls_ccm_setkey( &ctx, MBEDTLS_CIPHER_ID_AES, key_test_data,
8 * sizeof key_test_data ) != 0 )
{
if( verbose != 0 )
mbedtls_printf( " CCM: setup failed" );
return( 1 );
}
for( i = 0; i < NB_TESTS; i++ )
{
if( verbose != 0 )
mbedtls_printf( " CCM-AES #%u: ", (unsigned int) i + 1 );
memset( plaintext, 0, CCM_SELFTEST_PT_MAX_LEN );
memset( ciphertext, 0, CCM_SELFTEST_CT_MAX_LEN );
memcpy( plaintext, msg_test_data, msg_len_test_data[i] );
ret = mbedtls_ccm_encrypt_and_tag( &ctx, msg_len_test_data[i],
iv_test_data, iv_len_test_data[i],
ad_test_data, add_len_test_data[i],
plaintext, ciphertext,
ciphertext + msg_len_test_data[i],
tag_len_test_data[i] );
if( ret != 0 ||
memcmp( ciphertext, res_test_data[i],
msg_len_test_data[i] + tag_len_test_data[i] ) != 0 )
{
if( verbose != 0 )
mbedtls_printf( "failed\n" );
return( 1 );
}
memset( plaintext, 0, CCM_SELFTEST_PT_MAX_LEN );
ret = mbedtls_ccm_auth_decrypt( &ctx, msg_len_test_data[i],
iv_test_data, iv_len_test_data[i],
ad_test_data, add_len_test_data[i],
ciphertext, plaintext,
ciphertext + msg_len_test_data[i],
tag_len_test_data[i] );
if( ret != 0 ||
memcmp( plaintext, msg_test_data, msg_len_test_data[i] ) != 0 )
{
if( verbose != 0 )
mbedtls_printf( "failed\n" );
return( 1 );
}
if( verbose != 0 )
mbedtls_printf( "passed\n" );
}
mbedtls_ccm_free( &ctx );
if( verbose != 0 )
mbedtls_printf( "\n" );
return( 0 );
}
#endif /* MBEDTLS_SELF_TEST && MBEDTLS_AES_C */
#endif /* MBEDTLS_CCM_C */