/* | |
* NIST SP800-38C compliant CCM 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 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" | |
*/ | |
#if !defined(MBEDTLS_CONFIG_FILE) | |
#include "mbedtls/config.h" | |
#else | |
#include MBEDTLS_CONFIG_FILE | |
#endif | |
#if defined(MBEDTLS_CCM_C) | |
#include "mbedtls/ccm.h" | |
#include "mbedtls/platform_util.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 ) | |
#define CCM_ENCRYPT 0 | |
#define CCM_DECRYPT 1 | |
/* | |
* 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; | |
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 ) ); | |
} | |
/* | |
* Macros for common operations. | |
* Results in smaller compiled code than static inline functions. | |
*/ | |
/* | |
* Update the CBC-MAC state in y using a block in b | |
* (Always using b as the source helps the compiler optimise a bit better.) | |
*/ | |
#define UPDATE_CBC_MAC \ | |
for( i = 0; i < 16; i++ ) \ | |
y[i] ^= b[i]; \ | |
\ | |
if( ( ret = mbedtls_cipher_update( &ctx->cipher_ctx, y, 16, y, &olen ) ) != 0 ) \ | |
return( ret ); | |
/* | |
* Encrypt or decrypt a partial block with CTR | |
* Warning: using b for temporary storage! src and dst must not be b! | |
* This avoids allocating one more 16 bytes buffer while allowing src == dst. | |
*/ | |
#define CTR_CRYPT( dst, src, len ) \ | |
do \ | |
{ \ | |
if( ( ret = mbedtls_cipher_update( &ctx->cipher_ctx, ctr, \ | |
16, b, &olen ) ) != 0 ) \ | |
{ \ | |
return( ret ); \ | |
} \ | |
\ | |
for( i = 0; i < (len); i++ ) \ | |
(dst)[i] = (src)[i] ^ b[i]; \ | |
} while( 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; | |
unsigned char i; | |
unsigned char q; | |
size_t len_left, olen; | |
unsigned char b[16]; | |
unsigned char y[16]; | |
unsigned char ctr[16]; | |
const unsigned char *src; | |
unsigned char *dst; | |
/* | |
* 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 ); | |
/* Also implies q is within bounds */ | |
if( iv_len < 7 || iv_len > 13 ) | |
return( MBEDTLS_ERR_CCM_BAD_INPUT ); | |
if( add_len > 0xFF00 ) | |
return( MBEDTLS_ERR_CCM_BAD_INPUT ); | |
q = 16 - 1 - (unsigned char) iv_len; | |
/* | |
* First block B_0: | |
* 0 .. 0 flags | |
* 1 .. iv_len nonce (aka iv) | |
* iv_len+1 .. 15 length | |
* | |
* With flags as (bits): | |
* 7 0 | |
* 6 add present? | |
* 5 .. 3 (t - 2) / 2 | |
* 2 .. 0 q - 1 | |
*/ | |
b[0] = 0; | |
b[0] |= ( add_len > 0 ) << 6; | |
b[0] |= ( ( tag_len - 2 ) / 2 ) << 3; | |
b[0] |= q - 1; | |
memcpy( b + 1, iv, iv_len ); | |
for( i = 0, len_left = length; i < q; i++, len_left >>= 8 ) | |
b[15-i] = (unsigned char)( len_left & 0xFF ); | |
if( len_left > 0 ) | |
return( MBEDTLS_ERR_CCM_BAD_INPUT ); | |
/* Start CBC-MAC with first block */ | |
memset( y, 0, 16 ); | |
UPDATE_CBC_MAC; | |
/* | |
* If there is additional data, update CBC-MAC with | |
* add_len, add, 0 (padding to a block boundary) | |
*/ | |
if( add_len > 0 ) | |
{ | |
size_t use_len; | |
len_left = add_len; | |
src = add; | |
memset( b, 0, 16 ); | |
b[0] = (unsigned char)( ( add_len >> 8 ) & 0xFF ); | |
b[1] = (unsigned char)( ( add_len ) & 0xFF ); | |
use_len = len_left < 16 - 2 ? len_left : 16 - 2; | |
memcpy( b + 2, src, use_len ); | |
len_left -= use_len; | |
src += use_len; | |
UPDATE_CBC_MAC; | |
while( len_left > 0 ) | |
{ | |
use_len = len_left > 16 ? 16 : len_left; | |
memset( b, 0, 16 ); | |
memcpy( b, src, use_len ); | |
UPDATE_CBC_MAC; | |
len_left -= use_len; | |
src += use_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 | |
*/ | |
ctr[0] = q - 1; | |
memcpy( ctr + 1, iv, iv_len ); | |
memset( ctr + 1 + iv_len, 0, q ); | |
ctr[15] = 1; | |
/* | |
* Authenticate and {en,de}crypt the message. | |
* | |
* The only difference between encryption and decryption is | |
* the respective order of authentication and {en,de}cryption. | |
*/ | |
len_left = length; | |
src = input; | |
dst = output; | |
while( len_left > 0 ) | |
{ | |
size_t use_len = len_left > 16 ? 16 : len_left; | |
if( mode == CCM_ENCRYPT ) | |
{ | |
memset( b, 0, 16 ); | |
memcpy( b, src, use_len ); | |
UPDATE_CBC_MAC; | |
} | |
CTR_CRYPT( dst, src, use_len ); | |
if( mode == CCM_DECRYPT ) | |
{ | |
memset( b, 0, 16 ); | |
memcpy( b, dst, use_len ); | |
UPDATE_CBC_MAC; | |
} | |
dst += use_len; | |
src += use_len; | |
len_left -= use_len; | |
/* | |
* Increment counter. | |
* No need to check for overflow thanks to the length check above. | |
*/ | |
for( i = 0; i < q; i++ ) | |
if( ++ctr[15-i] != 0 ) | |
break; | |
} | |
/* | |
* Authentication: reset counter and crypt/mask internal tag | |
*/ | |
for( i = 0; i < q; i++ ) | |
ctr[15-i] = 0; | |
CTR_CRYPT( y, y, 16 ); | |
memcpy( tag, y, tag_len ); | |
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 ) | |
{ | |
CCM_VALIDATE_RET( ctx != NULL ); | |
CCM_VALIDATE_RET( iv != NULL ); | |
CCM_VALIDATE_RET( add_len == 0 || add != NULL ); | |
CCM_VALIDATE_RET( length == 0 || input != NULL ); | |
CCM_VALIDATE_RET( length == 0 || output != NULL ); | |
CCM_VALIDATE_RET( tag_len == 0 || tag != NULL ); | |
return( ccm_auth_crypt( ctx, CCM_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 ) | |
{ | |
CCM_VALIDATE_RET( ctx != NULL ); | |
CCM_VALIDATE_RET( iv != NULL ); | |
CCM_VALIDATE_RET( add_len == 0 || add != NULL ); | |
CCM_VALIDATE_RET( length == 0 || input != NULL ); | |
CCM_VALIDATE_RET( length == 0 || output != NULL ); | |
CCM_VALIDATE_RET( tag_len == 0 || tag != NULL ); | |
if( tag_len == 0 ) | |
return( MBEDTLS_ERR_CCM_BAD_INPUT ); | |
return( mbedtls_ccm_star_encrypt_and_tag( ctx, length, iv, iv_len, add, | |
add_len, input, output, tag, tag_len ) ); | |
} | |
/* | |
* 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; | |
unsigned char check_tag[16]; | |
unsigned char i; | |
int diff; | |
CCM_VALIDATE_RET( ctx != NULL ); | |
CCM_VALIDATE_RET( iv != NULL ); | |
CCM_VALIDATE_RET( add_len == 0 || add != NULL ); | |
CCM_VALIDATE_RET( length == 0 || input != NULL ); | |
CCM_VALIDATE_RET( length == 0 || output != NULL ); | |
CCM_VALIDATE_RET( tag_len == 0 || tag != NULL ); | |
if( ( ret = ccm_auth_crypt( ctx, CCM_DECRYPT, length, | |
iv, iv_len, add, add_len, | |
input, output, 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 ) | |
{ | |
mbedtls_platform_zeroize( output, length ); | |
return( MBEDTLS_ERR_CCM_AUTH_FAILED ); | |
} | |
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 ) | |
{ | |
CCM_VALIDATE_RET( ctx != NULL ); | |
CCM_VALIDATE_RET( iv != NULL ); | |
CCM_VALIDATE_RET( add_len == 0 || add != NULL ); | |
CCM_VALIDATE_RET( length == 0 || input != NULL ); | |
CCM_VALIDATE_RET( length == 0 || output != NULL ); | |
CCM_VALIDATE_RET( tag_len == 0 || tag != NULL ); | |
if( tag_len == 0 ) | |
return( MBEDTLS_ERR_CCM_BAD_INPUT ); | |
return( mbedtls_ccm_star_auth_decrypt( ctx, length, iv, iv_len, add, | |
add_len, input, output, tag, tag_len ) ); | |
} | |
#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_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 */ |