mirror of
https://github.com/yuzu-emu/mbedtls.git
synced 2024-12-24 00:15:35 +00:00
70261c513a
Add new initializers for key policies and use them in our docs, example programs, tests, and library code. Prefer using the macro initializers due to their straightforwardness.
721 lines
26 KiB
C
721 lines
26 KiB
C
/**
|
|
* PSA API key derivation demonstration
|
|
*
|
|
* This program calculates a key ladder: a chain of secret material, each
|
|
* derived from the previous one in a deterministic way based on a label.
|
|
* Two keys are identical if and only if they are derived from the same key
|
|
* using the same label.
|
|
*
|
|
* The initial key is called the master key. The master key is normally
|
|
* randomly generated, but it could itself be derived from another key.
|
|
*
|
|
* This program derives a series of keys called intermediate keys.
|
|
* The first intermediate key is derived from the master key using the
|
|
* first label passed on the command line. Each subsequent intermediate
|
|
* key is derived from the previous one using the next label passed
|
|
* on the command line.
|
|
*
|
|
* This program has four modes of operation:
|
|
*
|
|
* - "generate": generate a random master key.
|
|
* - "wrap": derive a wrapping key from the last intermediate key,
|
|
* and use that key to encrypt-and-authenticate some data.
|
|
* - "unwrap": derive a wrapping key from the last intermediate key,
|
|
* and use that key to decrypt-and-authenticate some
|
|
* ciphertext created by wrap mode.
|
|
* - "save": save the last intermediate key so that it can be reused as
|
|
* the master key in another run of the program.
|
|
*
|
|
* See the usage() output for the command line usage. See the file
|
|
* `key_ladder_demo.sh` for an example run.
|
|
*/
|
|
|
|
/* Copyright (C) 2018, 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)
|
|
*/
|
|
|
|
/* First include Mbed TLS headers to get the Mbed TLS configuration and
|
|
* platform definitions that we'll use in this program. Also include
|
|
* standard C headers for functions we'll use here. */
|
|
#if !defined(MBEDTLS_CONFIG_FILE)
|
|
#include "mbedtls/config.h"
|
|
#else
|
|
#include MBEDTLS_CONFIG_FILE
|
|
#endif
|
|
|
|
#if defined(MBEDTLS_PLATFORM_C)
|
|
#include "mbedtls/platform.h"
|
|
#else
|
|
#include <stdlib.h>
|
|
#define MBEDTLS_EXIT_SUCCESS EXIT_SUCCESS
|
|
#define MBEDTLS_EXIT_FAILURE EXIT_FAILURE
|
|
#define mbedtls_calloc calloc
|
|
#define mbedtls_free free
|
|
#define mbedtls_printf printf
|
|
#endif
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
|
|
#include "mbedtls/platform_util.h" // for mbedtls_platform_zeroize
|
|
|
|
/* If the build options we need are not enabled, compile a placeholder. */
|
|
#if !defined(MBEDTLS_SHA256_C) || !defined(MBEDTLS_MD_C) || \
|
|
!defined(MBEDTLS_AES_C) || !defined(MBEDTLS_CCM_C) || \
|
|
!defined(MBEDTLS_PSA_CRYPTO_C) || !defined(MBEDTLS_FS_IO)
|
|
int main( void )
|
|
{
|
|
mbedtls_printf("MBEDTLS_SHA256_C and/or MBEDTLS_MD_C and/or "
|
|
"MBEDTLS_AES_C and/or MBEDTLS_CCM_C and/or "
|
|
"MBEDTLS_PSA_CRYPTO_C and/or MBEDTLS_FS_IO not defined.\n");
|
|
return( 0 );
|
|
}
|
|
#else
|
|
|
|
/* The real program starts here. */
|
|
|
|
|
|
|
|
#include <psa/crypto.h>
|
|
|
|
/* Run a system function and bail out if it fails. */
|
|
#define SYS_CHECK( expr ) \
|
|
do \
|
|
{ \
|
|
if( ! ( expr ) ) \
|
|
{ \
|
|
perror( #expr ); \
|
|
status = DEMO_ERROR; \
|
|
goto exit; \
|
|
} \
|
|
} \
|
|
while( 0 )
|
|
|
|
/* Run a PSA function and bail out if it fails. */
|
|
#define PSA_CHECK( expr ) \
|
|
do \
|
|
{ \
|
|
status = ( expr ); \
|
|
if( status != PSA_SUCCESS ) \
|
|
{ \
|
|
mbedtls_printf( "Error %d at line %u: %s\n", \
|
|
(int) status, \
|
|
__LINE__, \
|
|
#expr ); \
|
|
goto exit; \
|
|
} \
|
|
} \
|
|
while( 0 )
|
|
|
|
/* To report operational errors in this program, use an error code that is
|
|
* different from every PSA error code. */
|
|
#define DEMO_ERROR 120
|
|
|
|
/* The maximum supported key ladder depth. */
|
|
#define MAX_LADDER_DEPTH 10
|
|
|
|
/* Salt to use when deriving an intermediate key. */
|
|
#define DERIVE_KEY_SALT ( (uint8_t *) "key_ladder_demo.derive" )
|
|
#define DERIVE_KEY_SALT_LENGTH ( strlen( (const char*) DERIVE_KEY_SALT ) )
|
|
|
|
/* Salt to use when deriving a wrapping key. */
|
|
#define WRAPPING_KEY_SALT ( (uint8_t *) "key_ladder_demo.wrap" )
|
|
#define WRAPPING_KEY_SALT_LENGTH ( strlen( (const char*) WRAPPING_KEY_SALT ) )
|
|
|
|
/* Size of the key derivation keys (applies both to the master key and
|
|
* to intermediate keys). */
|
|
#define KEY_SIZE_BYTES 40
|
|
|
|
/* Algorithm for key derivation. */
|
|
#define KDF_ALG PSA_ALG_HKDF( PSA_ALG_SHA_256 )
|
|
|
|
/* Type and size of the key used to wrap data. */
|
|
#define WRAPPING_KEY_TYPE PSA_KEY_TYPE_AES
|
|
#define WRAPPING_KEY_BITS 128
|
|
|
|
/* Cipher mode used to wrap data. */
|
|
#define WRAPPING_ALG PSA_ALG_CCM
|
|
|
|
/* Nonce size used to wrap data. */
|
|
#define WRAPPING_IV_SIZE 13
|
|
|
|
/* Header used in files containing wrapped data. We'll save this header
|
|
* directly without worrying about data representation issues such as
|
|
* integer sizes and endianness, because the data is meant to be read
|
|
* back by the same program on the same machine. */
|
|
#define WRAPPED_DATA_MAGIC "key_ladder_demo" // including trailing null byte
|
|
#define WRAPPED_DATA_MAGIC_LENGTH ( sizeof( WRAPPED_DATA_MAGIC ) )
|
|
typedef struct
|
|
{
|
|
char magic[WRAPPED_DATA_MAGIC_LENGTH];
|
|
size_t ad_size; /* Size of the additional data, which is this header. */
|
|
size_t payload_size; /* Size of the encrypted data. */
|
|
/* Store the IV inside the additional data. It's convenient. */
|
|
uint8_t iv[WRAPPING_IV_SIZE];
|
|
} wrapped_data_header_t;
|
|
|
|
/* The modes that this program can operate in (see usage). */
|
|
enum program_mode
|
|
{
|
|
MODE_GENERATE,
|
|
MODE_SAVE,
|
|
MODE_UNWRAP,
|
|
MODE_WRAP
|
|
};
|
|
|
|
/* Save a key to a file. In the real world, you may want to export a derived
|
|
* key sometimes, to share it with another party. */
|
|
static psa_status_t save_key( psa_key_handle_t key_handle,
|
|
const char *output_file_name )
|
|
{
|
|
psa_status_t status = PSA_SUCCESS;
|
|
uint8_t key_data[KEY_SIZE_BYTES];
|
|
size_t key_size;
|
|
FILE *key_file = NULL;
|
|
|
|
PSA_CHECK( psa_export_key( key_handle,
|
|
key_data, sizeof( key_data ),
|
|
&key_size ) );
|
|
SYS_CHECK( ( key_file = fopen( output_file_name, "wb" ) ) != NULL );
|
|
SYS_CHECK( fwrite( key_data, 1, key_size, key_file ) == key_size );
|
|
SYS_CHECK( fclose( key_file ) == 0 );
|
|
key_file = NULL;
|
|
|
|
exit:
|
|
if( key_file != NULL)
|
|
fclose( key_file );
|
|
return( status );
|
|
}
|
|
|
|
/* Generate a master key for use in this demo.
|
|
*
|
|
* Normally a master key would be non-exportable. For the purpose of this
|
|
* demo, we want to save it to a file, to avoid relying on the keystore
|
|
* capability of the PSA crypto library. */
|
|
static psa_status_t generate( const char *key_file_name )
|
|
{
|
|
psa_status_t status = PSA_SUCCESS;
|
|
psa_key_handle_t key_handle = 0;
|
|
psa_key_policy_t policy = PSA_KEY_POLICY_INIT;
|
|
|
|
PSA_CHECK( psa_allocate_key( PSA_KEY_TYPE_DERIVE,
|
|
PSA_BYTES_TO_BITS( KEY_SIZE_BYTES ),
|
|
&key_handle ) );
|
|
psa_key_policy_set_usage( &policy,
|
|
PSA_KEY_USAGE_DERIVE | PSA_KEY_USAGE_EXPORT,
|
|
KDF_ALG );
|
|
PSA_CHECK( psa_set_key_policy( key_handle, &policy ) );
|
|
|
|
PSA_CHECK( psa_generate_key( key_handle,
|
|
PSA_KEY_TYPE_DERIVE,
|
|
PSA_BYTES_TO_BITS( KEY_SIZE_BYTES ),
|
|
NULL, 0 ) );
|
|
|
|
PSA_CHECK( save_key( key_handle, key_file_name ) );
|
|
|
|
exit:
|
|
(void) psa_destroy_key( key_handle );
|
|
return( status );
|
|
}
|
|
|
|
/* Load the master key from a file.
|
|
*
|
|
* In the real world, this master key would be stored in an internal memory
|
|
* and the storage would be managed by the keystore capability of the PSA
|
|
* crypto library. */
|
|
static psa_status_t import_key_from_file( psa_key_usage_t usage,
|
|
psa_algorithm_t alg,
|
|
const char *key_file_name,
|
|
psa_key_handle_t *master_key_handle )
|
|
{
|
|
psa_status_t status = PSA_SUCCESS;
|
|
psa_key_policy_t policy = PSA_KEY_POLICY_INIT;
|
|
uint8_t key_data[KEY_SIZE_BYTES];
|
|
size_t key_size;
|
|
FILE *key_file = NULL;
|
|
unsigned char extra_byte;
|
|
|
|
*master_key_handle = 0;
|
|
|
|
SYS_CHECK( ( key_file = fopen( key_file_name, "rb" ) ) != NULL );
|
|
SYS_CHECK( ( key_size = fread( key_data, 1, sizeof( key_data ),
|
|
key_file ) ) != 0 );
|
|
if( fread( &extra_byte, 1, 1, key_file ) != 0 )
|
|
{
|
|
mbedtls_printf( "Key file too large (max: %u).\n",
|
|
(unsigned) sizeof( key_data ) );
|
|
status = DEMO_ERROR;
|
|
goto exit;
|
|
}
|
|
SYS_CHECK( fclose( key_file ) == 0 );
|
|
key_file = NULL;
|
|
|
|
PSA_CHECK( psa_allocate_key( PSA_KEY_TYPE_DERIVE,
|
|
PSA_BYTES_TO_BITS( key_size ),
|
|
master_key_handle ) );
|
|
psa_key_policy_set_usage( &policy, usage, alg );
|
|
PSA_CHECK( psa_set_key_policy( *master_key_handle, &policy ) );
|
|
PSA_CHECK( psa_import_key( *master_key_handle,
|
|
PSA_KEY_TYPE_DERIVE,
|
|
key_data, key_size ) );
|
|
exit:
|
|
if( key_file != NULL )
|
|
fclose( key_file );
|
|
mbedtls_platform_zeroize( key_data, sizeof( key_data ) );
|
|
if( status != PSA_SUCCESS )
|
|
{
|
|
/* If psa_allocate_key hasn't been called yet or has failed,
|
|
* *master_key_handle is 0. psa_destroy_key(0) is guaranteed to do
|
|
* nothing and return PSA_ERROR_INVALID_HANDLE. */
|
|
(void) psa_destroy_key( *master_key_handle );
|
|
*master_key_handle = 0;
|
|
}
|
|
return( status );
|
|
}
|
|
|
|
/* Derive the intermediate keys, using the list of labels provided on
|
|
* the command line. On input, *key_handle is a handle to the master key.
|
|
* This function closes the master key. On successful output, *key_handle
|
|
* is a handle to the final derived key. */
|
|
static psa_status_t derive_key_ladder( const char *ladder[],
|
|
size_t ladder_depth,
|
|
psa_key_handle_t *key_handle )
|
|
{
|
|
psa_status_t status = PSA_SUCCESS;
|
|
psa_key_policy_t policy = PSA_KEY_POLICY_INIT;
|
|
psa_crypto_generator_t generator = PSA_CRYPTO_GENERATOR_INIT;
|
|
size_t i;
|
|
psa_key_policy_set_usage( &policy,
|
|
PSA_KEY_USAGE_DERIVE | PSA_KEY_USAGE_EXPORT,
|
|
KDF_ALG );
|
|
|
|
/* For each label in turn, ... */
|
|
for( i = 0; i < ladder_depth; i++ )
|
|
{
|
|
/* Start deriving material from the master key (if i=0) or from
|
|
* the current intermediate key (if i>0). */
|
|
PSA_CHECK( psa_key_derivation(
|
|
&generator,
|
|
*key_handle,
|
|
KDF_ALG,
|
|
DERIVE_KEY_SALT, DERIVE_KEY_SALT_LENGTH,
|
|
(uint8_t*) ladder[i], strlen( ladder[i] ),
|
|
KEY_SIZE_BYTES ) );
|
|
/* When the parent key is not the master key, destroy it,
|
|
* since it is no longer needed. */
|
|
PSA_CHECK( psa_close_key( *key_handle ) );
|
|
*key_handle = 0;
|
|
PSA_CHECK( psa_allocate_key( PSA_KEY_TYPE_DERIVE,
|
|
PSA_BYTES_TO_BITS( KEY_SIZE_BYTES ),
|
|
key_handle ) );
|
|
PSA_CHECK( psa_set_key_policy( *key_handle, &policy ) );
|
|
/* Use the generator obtained from the parent key to create
|
|
* the next intermediate key. */
|
|
PSA_CHECK( psa_generator_import_key(
|
|
*key_handle,
|
|
PSA_KEY_TYPE_DERIVE,
|
|
PSA_BYTES_TO_BITS( KEY_SIZE_BYTES ),
|
|
&generator ) );
|
|
PSA_CHECK( psa_generator_abort( &generator ) );
|
|
}
|
|
|
|
exit:
|
|
psa_generator_abort( &generator );
|
|
if( status != PSA_SUCCESS )
|
|
{
|
|
psa_close_key( *key_handle );
|
|
*key_handle = 0;
|
|
}
|
|
return( status );
|
|
}
|
|
|
|
/* Derive a wrapping key from the last intermediate key. */
|
|
static psa_status_t derive_wrapping_key( psa_key_usage_t usage,
|
|
psa_key_handle_t derived_key_handle,
|
|
psa_key_handle_t *wrapping_key_handle )
|
|
{
|
|
psa_status_t status = PSA_SUCCESS;
|
|
psa_key_policy_t policy = PSA_KEY_POLICY_INIT;
|
|
psa_crypto_generator_t generator = PSA_CRYPTO_GENERATOR_INIT;
|
|
|
|
*wrapping_key_handle = 0;
|
|
PSA_CHECK( psa_allocate_key( PSA_KEY_TYPE_AES, WRAPPING_KEY_BITS,
|
|
wrapping_key_handle ) );
|
|
psa_key_policy_set_usage( &policy, usage, WRAPPING_ALG );
|
|
PSA_CHECK( psa_set_key_policy( *wrapping_key_handle, &policy ) );
|
|
|
|
PSA_CHECK( psa_key_derivation(
|
|
&generator,
|
|
derived_key_handle,
|
|
KDF_ALG,
|
|
WRAPPING_KEY_SALT, WRAPPING_KEY_SALT_LENGTH,
|
|
NULL, 0,
|
|
PSA_BITS_TO_BYTES( WRAPPING_KEY_BITS ) ) );
|
|
PSA_CHECK( psa_generator_import_key(
|
|
*wrapping_key_handle,
|
|
PSA_KEY_TYPE_AES,
|
|
WRAPPING_KEY_BITS,
|
|
&generator ) );
|
|
|
|
exit:
|
|
psa_generator_abort( &generator );
|
|
if( status != PSA_SUCCESS )
|
|
{
|
|
psa_close_key( *wrapping_key_handle );
|
|
*wrapping_key_handle = 0;
|
|
}
|
|
return( status );
|
|
}
|
|
|
|
static psa_status_t wrap_data( const char *input_file_name,
|
|
const char *output_file_name,
|
|
psa_key_handle_t wrapping_key_handle )
|
|
{
|
|
psa_status_t status;
|
|
FILE *input_file = NULL;
|
|
FILE *output_file = NULL;
|
|
long input_position;
|
|
size_t input_size;
|
|
size_t buffer_size = 0;
|
|
unsigned char *buffer = NULL;
|
|
size_t ciphertext_size;
|
|
wrapped_data_header_t header;
|
|
|
|
/* Find the size of the data to wrap. */
|
|
SYS_CHECK( ( input_file = fopen( input_file_name, "rb" ) ) != NULL );
|
|
SYS_CHECK( fseek( input_file, 0, SEEK_END ) == 0 );
|
|
SYS_CHECK( ( input_position = ftell( input_file ) ) != -1 );
|
|
#if LONG_MAX > SIZE_MAX
|
|
if( input_position > SIZE_MAX )
|
|
{
|
|
mbedtls_printf( "Input file too large.\n" );
|
|
status = DEMO_ERROR;
|
|
goto exit;
|
|
}
|
|
#endif
|
|
input_size = input_position;
|
|
buffer_size = PSA_AEAD_ENCRYPT_OUTPUT_SIZE( WRAPPING_ALG, input_size );
|
|
/* Check for integer overflow. */
|
|
if( buffer_size < input_size )
|
|
{
|
|
mbedtls_printf( "Input file too large.\n" );
|
|
status = DEMO_ERROR;
|
|
goto exit;
|
|
}
|
|
|
|
/* Load the data to wrap. */
|
|
SYS_CHECK( fseek( input_file, 0, SEEK_SET ) == 0 );
|
|
SYS_CHECK( ( buffer = mbedtls_calloc( 1, buffer_size ) ) != NULL );
|
|
SYS_CHECK( fread( buffer, 1, input_size, input_file ) == input_size );
|
|
SYS_CHECK( fclose( input_file ) == 0 );
|
|
input_file = NULL;
|
|
|
|
/* Construct a header. */
|
|
memcpy( &header.magic, WRAPPED_DATA_MAGIC, WRAPPED_DATA_MAGIC_LENGTH );
|
|
header.ad_size = sizeof( header );
|
|
header.payload_size = input_size;
|
|
|
|
/* Wrap the data. */
|
|
PSA_CHECK( psa_generate_random( header.iv, WRAPPING_IV_SIZE ) );
|
|
PSA_CHECK( psa_aead_encrypt( wrapping_key_handle, WRAPPING_ALG,
|
|
header.iv, WRAPPING_IV_SIZE,
|
|
(uint8_t *) &header, sizeof( header ),
|
|
buffer, input_size,
|
|
buffer, buffer_size,
|
|
&ciphertext_size ) );
|
|
|
|
/* Write the output. */
|
|
SYS_CHECK( ( output_file = fopen( output_file_name, "wb" ) ) != NULL );
|
|
SYS_CHECK( fwrite( &header, 1, sizeof( header ),
|
|
output_file ) == sizeof( header ) );
|
|
SYS_CHECK( fwrite( buffer, 1, ciphertext_size,
|
|
output_file ) == ciphertext_size );
|
|
SYS_CHECK( fclose( output_file ) == 0 );
|
|
output_file = NULL;
|
|
|
|
exit:
|
|
if( input_file != NULL )
|
|
fclose( input_file );
|
|
if( output_file != NULL )
|
|
fclose( output_file );
|
|
if( buffer != NULL )
|
|
mbedtls_platform_zeroize( buffer, buffer_size );
|
|
mbedtls_free( buffer );
|
|
return( status );
|
|
}
|
|
|
|
static psa_status_t unwrap_data( const char *input_file_name,
|
|
const char *output_file_name,
|
|
psa_key_handle_t wrapping_key_handle )
|
|
{
|
|
psa_status_t status;
|
|
FILE *input_file = NULL;
|
|
FILE *output_file = NULL;
|
|
unsigned char *buffer = NULL;
|
|
size_t ciphertext_size = 0;
|
|
size_t plaintext_size;
|
|
wrapped_data_header_t header;
|
|
unsigned char extra_byte;
|
|
|
|
/* Load and validate the header. */
|
|
SYS_CHECK( ( input_file = fopen( input_file_name, "rb" ) ) != NULL );
|
|
SYS_CHECK( fread( &header, 1, sizeof( header ),
|
|
input_file ) == sizeof( header ) );
|
|
if( memcmp( &header.magic, WRAPPED_DATA_MAGIC,
|
|
WRAPPED_DATA_MAGIC_LENGTH ) != 0 )
|
|
{
|
|
mbedtls_printf( "The input does not start with a valid magic header.\n" );
|
|
status = DEMO_ERROR;
|
|
goto exit;
|
|
}
|
|
if( header.ad_size != sizeof( header ) )
|
|
{
|
|
mbedtls_printf( "The header size is not correct.\n" );
|
|
status = DEMO_ERROR;
|
|
goto exit;
|
|
}
|
|
ciphertext_size =
|
|
PSA_AEAD_ENCRYPT_OUTPUT_SIZE( WRAPPING_ALG, header.payload_size );
|
|
/* Check for integer overflow. */
|
|
if( ciphertext_size < header.payload_size )
|
|
{
|
|
mbedtls_printf( "Input file too large.\n" );
|
|
status = DEMO_ERROR;
|
|
goto exit;
|
|
}
|
|
|
|
/* Load the payload data. */
|
|
SYS_CHECK( ( buffer = mbedtls_calloc( 1, ciphertext_size ) ) != NULL );
|
|
SYS_CHECK( fread( buffer, 1, ciphertext_size,
|
|
input_file ) == ciphertext_size );
|
|
if( fread( &extra_byte, 1, 1, input_file ) != 0 )
|
|
{
|
|
mbedtls_printf( "Extra garbage after ciphertext\n" );
|
|
status = DEMO_ERROR;
|
|
goto exit;
|
|
}
|
|
SYS_CHECK( fclose( input_file ) == 0 );
|
|
input_file = NULL;
|
|
|
|
/* Unwrap the data. */
|
|
PSA_CHECK( psa_aead_decrypt( wrapping_key_handle, WRAPPING_ALG,
|
|
header.iv, WRAPPING_IV_SIZE,
|
|
(uint8_t *) &header, sizeof( header ),
|
|
buffer, ciphertext_size,
|
|
buffer, ciphertext_size,
|
|
&plaintext_size ) );
|
|
if( plaintext_size != header.payload_size )
|
|
{
|
|
mbedtls_printf( "Incorrect payload size in the header.\n" );
|
|
status = DEMO_ERROR;
|
|
goto exit;
|
|
}
|
|
|
|
/* Write the output. */
|
|
SYS_CHECK( ( output_file = fopen( output_file_name, "wb" ) ) != NULL );
|
|
SYS_CHECK( fwrite( buffer, 1, plaintext_size,
|
|
output_file ) == plaintext_size );
|
|
SYS_CHECK( fclose( output_file ) == 0 );
|
|
output_file = NULL;
|
|
|
|
exit:
|
|
if( input_file != NULL )
|
|
fclose( input_file );
|
|
if( output_file != NULL )
|
|
fclose( output_file );
|
|
if( buffer != NULL )
|
|
mbedtls_platform_zeroize( buffer, ciphertext_size );
|
|
mbedtls_free( buffer );
|
|
return( status );
|
|
}
|
|
|
|
static psa_status_t run( enum program_mode mode,
|
|
const char *key_file_name,
|
|
const char *ladder[], size_t ladder_depth,
|
|
const char *input_file_name,
|
|
const char *output_file_name )
|
|
{
|
|
psa_status_t status = PSA_SUCCESS;
|
|
psa_key_handle_t derivation_key_handle = 0;
|
|
psa_key_handle_t wrapping_key_handle = 0;
|
|
|
|
/* Initialize the PSA crypto library. */
|
|
PSA_CHECK( psa_crypto_init( ) );
|
|
|
|
/* Generate mode is unlike the others. Generate the master key and exit. */
|
|
if( mode == MODE_GENERATE )
|
|
return( generate( key_file_name ) );
|
|
|
|
/* Read the master key. */
|
|
PSA_CHECK( import_key_from_file( PSA_KEY_USAGE_DERIVE | PSA_KEY_USAGE_EXPORT,
|
|
KDF_ALG,
|
|
key_file_name,
|
|
&derivation_key_handle ) );
|
|
|
|
/* Calculate the derived key for this session. */
|
|
PSA_CHECK( derive_key_ladder( ladder, ladder_depth,
|
|
&derivation_key_handle ) );
|
|
|
|
switch( mode )
|
|
{
|
|
case MODE_SAVE:
|
|
PSA_CHECK( save_key( derivation_key_handle, output_file_name ) );
|
|
break;
|
|
case MODE_UNWRAP:
|
|
PSA_CHECK( derive_wrapping_key( PSA_KEY_USAGE_DECRYPT,
|
|
derivation_key_handle,
|
|
&wrapping_key_handle ) );
|
|
PSA_CHECK( unwrap_data( input_file_name, output_file_name,
|
|
wrapping_key_handle ) );
|
|
break;
|
|
case MODE_WRAP:
|
|
PSA_CHECK( derive_wrapping_key( PSA_KEY_USAGE_ENCRYPT,
|
|
derivation_key_handle,
|
|
&wrapping_key_handle ) );
|
|
PSA_CHECK( wrap_data( input_file_name, output_file_name,
|
|
wrapping_key_handle ) );
|
|
break;
|
|
default:
|
|
/* Unreachable but some compilers don't realize it. */
|
|
break;
|
|
}
|
|
|
|
exit:
|
|
/* Close any remaining key. Deinitializing the crypto library would do
|
|
* this anyway, but explicitly closing handles makes the code easier
|
|
* to reuse. */
|
|
(void) psa_close_key( derivation_key_handle );
|
|
(void) psa_close_key( wrapping_key_handle );
|
|
/* Deinitialize the PSA crypto library. */
|
|
mbedtls_psa_crypto_free( );
|
|
return( status );
|
|
}
|
|
|
|
static void usage( void )
|
|
{
|
|
mbedtls_printf( "Usage: key_ladder_demo MODE [OPTION=VALUE]...\n" );
|
|
mbedtls_printf( "Demonstrate the usage of a key derivation ladder.\n" );
|
|
mbedtls_printf( "\n" );
|
|
mbedtls_printf( "Modes:\n" );
|
|
mbedtls_printf( " generate Generate the master key\n" );
|
|
mbedtls_printf( " save Save the derived key\n" );
|
|
mbedtls_printf( " unwrap Unwrap (decrypt) input with the derived key\n" );
|
|
mbedtls_printf( " wrap Wrap (encrypt) input with the derived key\n" );
|
|
mbedtls_printf( "\n" );
|
|
mbedtls_printf( "Options:\n" );
|
|
mbedtls_printf( " input=FILENAME Input file (required for wrap/unwrap)\n" );
|
|
mbedtls_printf( " master=FILENAME File containing the master key (default: master.key)\n" );
|
|
mbedtls_printf( " output=FILENAME Output file (required for save/wrap/unwrap)\n" );
|
|
mbedtls_printf( " label=TEXT Label for the key derivation.\n" );
|
|
mbedtls_printf( " This may be repeated multiple times.\n" );
|
|
mbedtls_printf( " To get the same key, you must use the same master key\n" );
|
|
mbedtls_printf( " and the same sequence of labels.\n" );
|
|
}
|
|
|
|
int main( int argc, char *argv[] )
|
|
{
|
|
char *key_file_name = "master.key";
|
|
char *input_file_name = NULL;
|
|
char *output_file_name = NULL;
|
|
const char *ladder[MAX_LADDER_DEPTH];
|
|
size_t ladder_depth = 0;
|
|
int i;
|
|
enum program_mode mode;
|
|
psa_status_t status;
|
|
|
|
if( argc <= 1 ||
|
|
strcmp( argv[1], "help" ) == 0 ||
|
|
strcmp( argv[1], "-help" ) == 0 ||
|
|
strcmp( argv[1], "--help" ) == 0 )
|
|
{
|
|
usage( );
|
|
return( MBEDTLS_EXIT_SUCCESS );
|
|
}
|
|
|
|
for( i = 2; i < argc; i++ )
|
|
{
|
|
char *q = strchr( argv[i], '=' );
|
|
if( q == NULL )
|
|
{
|
|
mbedtls_printf( "Missing argument to option %s\n", argv[i] );
|
|
goto usage_failure;
|
|
}
|
|
*q = 0;
|
|
++q;
|
|
if( strcmp( argv[i], "input" ) == 0 )
|
|
input_file_name = q;
|
|
else if( strcmp( argv[i], "label" ) == 0 )
|
|
{
|
|
if( ladder_depth == MAX_LADDER_DEPTH )
|
|
{
|
|
mbedtls_printf( "Maximum ladder depth %u exceeded.\n",
|
|
(unsigned) MAX_LADDER_DEPTH );
|
|
return( MBEDTLS_EXIT_FAILURE );
|
|
}
|
|
ladder[ladder_depth] = q;
|
|
++ladder_depth;
|
|
}
|
|
else if( strcmp( argv[i], "master" ) == 0 )
|
|
key_file_name = q;
|
|
else if( strcmp( argv[i], "output" ) == 0 )
|
|
output_file_name = q;
|
|
else
|
|
{
|
|
mbedtls_printf( "Unknown option: %s\n", argv[i] );
|
|
goto usage_failure;
|
|
}
|
|
}
|
|
|
|
if( strcmp( argv[1], "generate" ) == 0 )
|
|
mode = MODE_GENERATE;
|
|
else if( strcmp( argv[1], "save" ) == 0 )
|
|
mode = MODE_SAVE;
|
|
else if( strcmp( argv[1], "unwrap" ) == 0 )
|
|
mode = MODE_UNWRAP;
|
|
else if( strcmp( argv[1], "wrap" ) == 0 )
|
|
mode = MODE_WRAP;
|
|
else
|
|
{
|
|
mbedtls_printf( "Unknown action: %s\n", argv[1] );
|
|
goto usage_failure;
|
|
}
|
|
|
|
if( input_file_name == NULL &&
|
|
( mode == MODE_WRAP || mode == MODE_UNWRAP ) )
|
|
{
|
|
mbedtls_printf( "Required argument missing: input\n" );
|
|
return( DEMO_ERROR );
|
|
}
|
|
if( output_file_name == NULL &&
|
|
( mode == MODE_SAVE || mode == MODE_WRAP || mode == MODE_UNWRAP ) )
|
|
{
|
|
mbedtls_printf( "Required argument missing: output\n" );
|
|
return( DEMO_ERROR );
|
|
}
|
|
|
|
status = run( mode, key_file_name,
|
|
ladder, ladder_depth,
|
|
input_file_name, output_file_name );
|
|
return( status == PSA_SUCCESS ?
|
|
MBEDTLS_EXIT_SUCCESS :
|
|
MBEDTLS_EXIT_FAILURE );
|
|
|
|
usage_failure:
|
|
usage( );
|
|
return( MBEDTLS_EXIT_FAILURE );
|
|
}
|
|
#endif /* MBEDTLS_SHA256_C && MBEDTLS_MD_C && MBEDTLS_AES_C && MBEDTLS_CCM_C && MBEDTLS_PSA_CRYPTO_C && MBEDTLS_FS_IO */
|