816 lines
26 KiB
C
816 lines
26 KiB
C
/*
|
|
* CTR_DRBG implementation based on AES-256 (NIST SP 800-90)
|
|
*
|
|
* 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)
|
|
*/
|
|
/*
|
|
* The NIST SP 800-90 DRBGs are described in the following publication.
|
|
*
|
|
* http://csrc.nist.gov/publications/nistpubs/800-90/SP800-90revised_March2007.pdf
|
|
*/
|
|
|
|
#if !defined(MBEDTLS_CONFIG_FILE)
|
|
#include "mbedtls/config.h"
|
|
#else
|
|
#include MBEDTLS_CONFIG_FILE
|
|
#endif
|
|
|
|
#if defined(MBEDTLS_CTR_DRBG_C)
|
|
|
|
#include "mbedtls/ctr_drbg.h"
|
|
#include "mbedtls/platform_util.h"
|
|
#include "mbedtls/error.h"
|
|
|
|
#include <string.h>
|
|
|
|
#if defined(MBEDTLS_FS_IO)
|
|
#include <stdio.h>
|
|
#endif
|
|
|
|
#if defined(MBEDTLS_SELF_TEST)
|
|
#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 */
|
|
|
|
/*
|
|
* CTR_DRBG context initialization
|
|
*/
|
|
void mbedtls_ctr_drbg_init( mbedtls_ctr_drbg_context *ctx )
|
|
{
|
|
memset( ctx, 0, sizeof( mbedtls_ctr_drbg_context ) );
|
|
/* Indicate that the entropy nonce length is not set explicitly.
|
|
* See mbedtls_ctr_drbg_set_nonce_len(). */
|
|
ctx->reseed_counter = -1;
|
|
|
|
#if defined(MBEDTLS_THREADING_C)
|
|
mbedtls_mutex_init( &ctx->mutex );
|
|
#endif
|
|
}
|
|
|
|
void mbedtls_ctr_drbg_free( mbedtls_ctr_drbg_context *ctx )
|
|
{
|
|
if( ctx == NULL )
|
|
return;
|
|
|
|
#if defined(MBEDTLS_THREADING_C)
|
|
mbedtls_mutex_free( &ctx->mutex );
|
|
#endif
|
|
mbedtls_aes_free( &ctx->aes_ctx );
|
|
mbedtls_platform_zeroize( ctx, sizeof( mbedtls_ctr_drbg_context ) );
|
|
}
|
|
|
|
void mbedtls_ctr_drbg_set_prediction_resistance( mbedtls_ctr_drbg_context *ctx,
|
|
int resistance )
|
|
{
|
|
ctx->prediction_resistance = resistance;
|
|
}
|
|
|
|
void mbedtls_ctr_drbg_set_entropy_len( mbedtls_ctr_drbg_context *ctx,
|
|
size_t len )
|
|
{
|
|
ctx->entropy_len = len;
|
|
}
|
|
|
|
int mbedtls_ctr_drbg_set_nonce_len( mbedtls_ctr_drbg_context *ctx,
|
|
size_t len )
|
|
{
|
|
/* If mbedtls_ctr_drbg_seed() has already been called, it's
|
|
* too late. Return the error code that's closest to making sense. */
|
|
if( ctx->f_entropy != NULL )
|
|
return( MBEDTLS_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED );
|
|
|
|
if( len > MBEDTLS_CTR_DRBG_MAX_SEED_INPUT )
|
|
return( MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG );
|
|
#if SIZE_MAX > INT_MAX
|
|
/* This shouldn't be an issue because
|
|
* MBEDTLS_CTR_DRBG_MAX_SEED_INPUT < INT_MAX in any sensible
|
|
* configuration, but make sure anyway. */
|
|
if( len > INT_MAX )
|
|
return( MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG );
|
|
#endif
|
|
|
|
/* For backward compatibility with Mbed TLS <= 2.19, store the
|
|
* entropy nonce length in a field that already exists, but isn't
|
|
* used until after the initial seeding. */
|
|
/* Due to the capping of len above, the value fits in an int. */
|
|
ctx->reseed_counter = (int) len;
|
|
return( 0 );
|
|
}
|
|
|
|
void mbedtls_ctr_drbg_set_reseed_interval( mbedtls_ctr_drbg_context *ctx,
|
|
int interval )
|
|
{
|
|
ctx->reseed_interval = interval;
|
|
}
|
|
|
|
static int block_cipher_df( unsigned char *output,
|
|
const unsigned char *data, size_t data_len )
|
|
{
|
|
unsigned char buf[MBEDTLS_CTR_DRBG_MAX_SEED_INPUT +
|
|
MBEDTLS_CTR_DRBG_BLOCKSIZE + 16];
|
|
unsigned char tmp[MBEDTLS_CTR_DRBG_SEEDLEN];
|
|
unsigned char key[MBEDTLS_CTR_DRBG_KEYSIZE];
|
|
unsigned char chain[MBEDTLS_CTR_DRBG_BLOCKSIZE];
|
|
unsigned char *p, *iv;
|
|
mbedtls_aes_context aes_ctx;
|
|
int ret = 0;
|
|
|
|
int i, j;
|
|
size_t buf_len, use_len;
|
|
|
|
if( data_len > MBEDTLS_CTR_DRBG_MAX_SEED_INPUT )
|
|
return( MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG );
|
|
|
|
memset( buf, 0, MBEDTLS_CTR_DRBG_MAX_SEED_INPUT +
|
|
MBEDTLS_CTR_DRBG_BLOCKSIZE + 16 );
|
|
mbedtls_aes_init( &aes_ctx );
|
|
|
|
/*
|
|
* Construct IV (16 bytes) and S in buffer
|
|
* IV = Counter (in 32-bits) padded to 16 with zeroes
|
|
* S = Length input string (in 32-bits) || Length of output (in 32-bits) ||
|
|
* data || 0x80
|
|
* (Total is padded to a multiple of 16-bytes with zeroes)
|
|
*/
|
|
p = buf + MBEDTLS_CTR_DRBG_BLOCKSIZE;
|
|
*p++ = ( data_len >> 24 ) & 0xff;
|
|
*p++ = ( data_len >> 16 ) & 0xff;
|
|
*p++ = ( data_len >> 8 ) & 0xff;
|
|
*p++ = ( data_len ) & 0xff;
|
|
p += 3;
|
|
*p++ = MBEDTLS_CTR_DRBG_SEEDLEN;
|
|
memcpy( p, data, data_len );
|
|
p[data_len] = 0x80;
|
|
|
|
buf_len = MBEDTLS_CTR_DRBG_BLOCKSIZE + 8 + data_len + 1;
|
|
|
|
for( i = 0; i < MBEDTLS_CTR_DRBG_KEYSIZE; i++ )
|
|
key[i] = i;
|
|
|
|
if( ( ret = mbedtls_aes_setkey_enc( &aes_ctx, key,
|
|
MBEDTLS_CTR_DRBG_KEYBITS ) ) != 0 )
|
|
{
|
|
goto exit;
|
|
}
|
|
|
|
/*
|
|
* Reduce data to MBEDTLS_CTR_DRBG_SEEDLEN bytes of data
|
|
*/
|
|
for( j = 0; j < MBEDTLS_CTR_DRBG_SEEDLEN; j += MBEDTLS_CTR_DRBG_BLOCKSIZE )
|
|
{
|
|
p = buf;
|
|
memset( chain, 0, MBEDTLS_CTR_DRBG_BLOCKSIZE );
|
|
use_len = buf_len;
|
|
|
|
while( use_len > 0 )
|
|
{
|
|
for( i = 0; i < MBEDTLS_CTR_DRBG_BLOCKSIZE; i++ )
|
|
chain[i] ^= p[i];
|
|
p += MBEDTLS_CTR_DRBG_BLOCKSIZE;
|
|
use_len -= ( use_len >= MBEDTLS_CTR_DRBG_BLOCKSIZE ) ?
|
|
MBEDTLS_CTR_DRBG_BLOCKSIZE : use_len;
|
|
|
|
if( ( ret = mbedtls_aes_crypt_ecb( &aes_ctx, MBEDTLS_AES_ENCRYPT,
|
|
chain, chain ) ) != 0 )
|
|
{
|
|
goto exit;
|
|
}
|
|
}
|
|
|
|
memcpy( tmp + j, chain, MBEDTLS_CTR_DRBG_BLOCKSIZE );
|
|
|
|
/*
|
|
* Update IV
|
|
*/
|
|
buf[3]++;
|
|
}
|
|
|
|
/*
|
|
* Do final encryption with reduced data
|
|
*/
|
|
if( ( ret = mbedtls_aes_setkey_enc( &aes_ctx, tmp,
|
|
MBEDTLS_CTR_DRBG_KEYBITS ) ) != 0 )
|
|
{
|
|
goto exit;
|
|
}
|
|
iv = tmp + MBEDTLS_CTR_DRBG_KEYSIZE;
|
|
p = output;
|
|
|
|
for( j = 0; j < MBEDTLS_CTR_DRBG_SEEDLEN; j += MBEDTLS_CTR_DRBG_BLOCKSIZE )
|
|
{
|
|
if( ( ret = mbedtls_aes_crypt_ecb( &aes_ctx, MBEDTLS_AES_ENCRYPT,
|
|
iv, iv ) ) != 0 )
|
|
{
|
|
goto exit;
|
|
}
|
|
memcpy( p, iv, MBEDTLS_CTR_DRBG_BLOCKSIZE );
|
|
p += MBEDTLS_CTR_DRBG_BLOCKSIZE;
|
|
}
|
|
exit:
|
|
mbedtls_aes_free( &aes_ctx );
|
|
/*
|
|
* tidy up the stack
|
|
*/
|
|
mbedtls_platform_zeroize( buf, sizeof( buf ) );
|
|
mbedtls_platform_zeroize( tmp, sizeof( tmp ) );
|
|
mbedtls_platform_zeroize( key, sizeof( key ) );
|
|
mbedtls_platform_zeroize( chain, sizeof( chain ) );
|
|
if( 0 != ret )
|
|
{
|
|
/*
|
|
* wipe partial seed from memory
|
|
*/
|
|
mbedtls_platform_zeroize( output, MBEDTLS_CTR_DRBG_SEEDLEN );
|
|
}
|
|
|
|
return( ret );
|
|
}
|
|
|
|
/* CTR_DRBG_Update (SP 800-90A §10.2.1.2)
|
|
* ctr_drbg_update_internal(ctx, provided_data)
|
|
* implements
|
|
* CTR_DRBG_Update(provided_data, Key, V)
|
|
* with inputs and outputs
|
|
* ctx->aes_ctx = Key
|
|
* ctx->counter = V
|
|
*/
|
|
static int ctr_drbg_update_internal( mbedtls_ctr_drbg_context *ctx,
|
|
const unsigned char data[MBEDTLS_CTR_DRBG_SEEDLEN] )
|
|
{
|
|
unsigned char tmp[MBEDTLS_CTR_DRBG_SEEDLEN];
|
|
unsigned char *p = tmp;
|
|
int i, j;
|
|
int ret = 0;
|
|
|
|
memset( tmp, 0, MBEDTLS_CTR_DRBG_SEEDLEN );
|
|
|
|
for( j = 0; j < MBEDTLS_CTR_DRBG_SEEDLEN; j += MBEDTLS_CTR_DRBG_BLOCKSIZE )
|
|
{
|
|
/*
|
|
* Increase counter
|
|
*/
|
|
for( i = MBEDTLS_CTR_DRBG_BLOCKSIZE; i > 0; i-- )
|
|
if( ++ctx->counter[i - 1] != 0 )
|
|
break;
|
|
|
|
/*
|
|
* Crypt counter block
|
|
*/
|
|
if( ( ret = mbedtls_aes_crypt_ecb( &ctx->aes_ctx, MBEDTLS_AES_ENCRYPT,
|
|
ctx->counter, p ) ) != 0 )
|
|
{
|
|
goto exit;
|
|
}
|
|
|
|
p += MBEDTLS_CTR_DRBG_BLOCKSIZE;
|
|
}
|
|
|
|
for( i = 0; i < MBEDTLS_CTR_DRBG_SEEDLEN; i++ )
|
|
tmp[i] ^= data[i];
|
|
|
|
/*
|
|
* Update key and counter
|
|
*/
|
|
if( ( ret = mbedtls_aes_setkey_enc( &ctx->aes_ctx, tmp,
|
|
MBEDTLS_CTR_DRBG_KEYBITS ) ) != 0 )
|
|
{
|
|
goto exit;
|
|
}
|
|
memcpy( ctx->counter, tmp + MBEDTLS_CTR_DRBG_KEYSIZE,
|
|
MBEDTLS_CTR_DRBG_BLOCKSIZE );
|
|
|
|
exit:
|
|
mbedtls_platform_zeroize( tmp, sizeof( tmp ) );
|
|
return( ret );
|
|
}
|
|
|
|
/* CTR_DRBG_Instantiate with derivation function (SP 800-90A §10.2.1.3.2)
|
|
* mbedtls_ctr_drbg_update(ctx, additional, add_len)
|
|
* implements
|
|
* CTR_DRBG_Instantiate(entropy_input, nonce, personalization_string,
|
|
* security_strength) -> initial_working_state
|
|
* with inputs
|
|
* ctx->counter = all-bits-0
|
|
* ctx->aes_ctx = context from all-bits-0 key
|
|
* additional[:add_len] = entropy_input || nonce || personalization_string
|
|
* and with outputs
|
|
* ctx = initial_working_state
|
|
*/
|
|
int mbedtls_ctr_drbg_update_ret( mbedtls_ctr_drbg_context *ctx,
|
|
const unsigned char *additional,
|
|
size_t add_len )
|
|
{
|
|
unsigned char add_input[MBEDTLS_CTR_DRBG_SEEDLEN];
|
|
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
|
|
|
|
if( add_len == 0 )
|
|
return( 0 );
|
|
|
|
if( ( ret = block_cipher_df( add_input, additional, add_len ) ) != 0 )
|
|
goto exit;
|
|
if( ( ret = ctr_drbg_update_internal( ctx, add_input ) ) != 0 )
|
|
goto exit;
|
|
|
|
exit:
|
|
mbedtls_platform_zeroize( add_input, sizeof( add_input ) );
|
|
return( ret );
|
|
}
|
|
|
|
#if !defined(MBEDTLS_DEPRECATED_REMOVED)
|
|
void mbedtls_ctr_drbg_update( mbedtls_ctr_drbg_context *ctx,
|
|
const unsigned char *additional,
|
|
size_t add_len )
|
|
{
|
|
/* MAX_INPUT would be more logical here, but we have to match
|
|
* block_cipher_df()'s limits since we can't propagate errors */
|
|
if( add_len > MBEDTLS_CTR_DRBG_MAX_SEED_INPUT )
|
|
add_len = MBEDTLS_CTR_DRBG_MAX_SEED_INPUT;
|
|
(void) mbedtls_ctr_drbg_update_ret( ctx, additional, add_len );
|
|
}
|
|
#endif /* MBEDTLS_DEPRECATED_REMOVED */
|
|
|
|
/* CTR_DRBG_Reseed with derivation function (SP 800-90A §10.2.1.4.2)
|
|
* mbedtls_ctr_drbg_reseed(ctx, additional, len, nonce_len)
|
|
* implements
|
|
* CTR_DRBG_Reseed(working_state, entropy_input, additional_input)
|
|
* -> new_working_state
|
|
* with inputs
|
|
* ctx contains working_state
|
|
* additional[:len] = additional_input
|
|
* and entropy_input comes from calling ctx->f_entropy
|
|
* for (ctx->entropy_len + nonce_len) bytes
|
|
* and with output
|
|
* ctx contains new_working_state
|
|
*/
|
|
static int mbedtls_ctr_drbg_reseed_internal( mbedtls_ctr_drbg_context *ctx,
|
|
const unsigned char *additional,
|
|
size_t len,
|
|
size_t nonce_len )
|
|
{
|
|
unsigned char seed[MBEDTLS_CTR_DRBG_MAX_SEED_INPUT];
|
|
size_t seedlen = 0;
|
|
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
|
|
|
|
if( ctx->entropy_len > MBEDTLS_CTR_DRBG_MAX_SEED_INPUT )
|
|
return( MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG );
|
|
if( nonce_len > MBEDTLS_CTR_DRBG_MAX_SEED_INPUT - ctx->entropy_len )
|
|
return( MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG );
|
|
if( len > MBEDTLS_CTR_DRBG_MAX_SEED_INPUT - ctx->entropy_len - nonce_len )
|
|
return( MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG );
|
|
|
|
memset( seed, 0, MBEDTLS_CTR_DRBG_MAX_SEED_INPUT );
|
|
|
|
/* Gather entropy_len bytes of entropy to seed state. */
|
|
if( 0 != ctx->f_entropy( ctx->p_entropy, seed, ctx->entropy_len ) )
|
|
{
|
|
return( MBEDTLS_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED );
|
|
}
|
|
seedlen += ctx->entropy_len;
|
|
|
|
/* Gather entropy for a nonce if requested. */
|
|
if( nonce_len != 0 )
|
|
{
|
|
if( 0 != ctx->f_entropy( ctx->p_entropy, seed, nonce_len ) )
|
|
{
|
|
return( MBEDTLS_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED );
|
|
}
|
|
seedlen += nonce_len;
|
|
}
|
|
|
|
/* Add additional data if provided. */
|
|
if( additional != NULL && len != 0 )
|
|
{
|
|
memcpy( seed + seedlen, additional, len );
|
|
seedlen += len;
|
|
}
|
|
|
|
/* Reduce to 384 bits. */
|
|
if( ( ret = block_cipher_df( seed, seed, seedlen ) ) != 0 )
|
|
goto exit;
|
|
|
|
/* Update state. */
|
|
if( ( ret = ctr_drbg_update_internal( ctx, seed ) ) != 0 )
|
|
goto exit;
|
|
ctx->reseed_counter = 1;
|
|
|
|
exit:
|
|
mbedtls_platform_zeroize( seed, sizeof( seed ) );
|
|
return( ret );
|
|
}
|
|
|
|
int mbedtls_ctr_drbg_reseed( mbedtls_ctr_drbg_context *ctx,
|
|
const unsigned char *additional, size_t len )
|
|
{
|
|
return( mbedtls_ctr_drbg_reseed_internal( ctx, additional, len, 0 ) );
|
|
}
|
|
|
|
/* Return a "good" nonce length for CTR_DRBG. The chosen nonce length
|
|
* is sufficient to achieve the maximum security strength given the key
|
|
* size and entropy length. If there is enough entropy in the initial
|
|
* call to the entropy function to serve as both the entropy input and
|
|
* the nonce, don't make a second call to get a nonce. */
|
|
static size_t good_nonce_len( size_t entropy_len )
|
|
{
|
|
if( entropy_len >= MBEDTLS_CTR_DRBG_KEYSIZE * 3 / 2 )
|
|
return( 0 );
|
|
else
|
|
return( ( entropy_len + 1 ) / 2 );
|
|
}
|
|
|
|
/* CTR_DRBG_Instantiate with derivation function (SP 800-90A §10.2.1.3.2)
|
|
* mbedtls_ctr_drbg_seed(ctx, f_entropy, p_entropy, custom, len)
|
|
* implements
|
|
* CTR_DRBG_Instantiate(entropy_input, nonce, personalization_string,
|
|
* security_strength) -> initial_working_state
|
|
* with inputs
|
|
* custom[:len] = nonce || personalization_string
|
|
* where entropy_input comes from f_entropy for ctx->entropy_len bytes
|
|
* and with outputs
|
|
* ctx = initial_working_state
|
|
*/
|
|
int mbedtls_ctr_drbg_seed( mbedtls_ctr_drbg_context *ctx,
|
|
int (*f_entropy)(void *, unsigned char *, size_t),
|
|
void *p_entropy,
|
|
const unsigned char *custom,
|
|
size_t len )
|
|
{
|
|
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
|
|
unsigned char key[MBEDTLS_CTR_DRBG_KEYSIZE];
|
|
size_t nonce_len;
|
|
|
|
memset( key, 0, MBEDTLS_CTR_DRBG_KEYSIZE );
|
|
|
|
mbedtls_aes_init( &ctx->aes_ctx );
|
|
|
|
ctx->f_entropy = f_entropy;
|
|
ctx->p_entropy = p_entropy;
|
|
|
|
if( ctx->entropy_len == 0 )
|
|
ctx->entropy_len = MBEDTLS_CTR_DRBG_ENTROPY_LEN;
|
|
/* ctx->reseed_counter contains the desired amount of entropy to
|
|
* grab for a nonce (see mbedtls_ctr_drbg_set_nonce_len()).
|
|
* If it's -1, indicating that the entropy nonce length was not set
|
|
* explicitly, use a sufficiently large nonce for security. */
|
|
nonce_len = ( ctx->reseed_counter >= 0 ?
|
|
(size_t) ctx->reseed_counter :
|
|
good_nonce_len( ctx->entropy_len ) );
|
|
|
|
ctx->reseed_interval = MBEDTLS_CTR_DRBG_RESEED_INTERVAL;
|
|
|
|
/* Initialize with an empty key. */
|
|
if( ( ret = mbedtls_aes_setkey_enc( &ctx->aes_ctx, key,
|
|
MBEDTLS_CTR_DRBG_KEYBITS ) ) != 0 )
|
|
{
|
|
return( ret );
|
|
}
|
|
|
|
/* Do the initial seeding. */
|
|
if( ( ret = mbedtls_ctr_drbg_reseed_internal( ctx, custom, len,
|
|
nonce_len ) ) != 0 )
|
|
{
|
|
return( ret );
|
|
}
|
|
return( 0 );
|
|
}
|
|
|
|
/* CTR_DRBG_Generate with derivation function (SP 800-90A §10.2.1.5.2)
|
|
* mbedtls_ctr_drbg_random_with_add(ctx, output, output_len, additional, add_len)
|
|
* implements
|
|
* CTR_DRBG_Reseed(working_state, entropy_input, additional[:add_len])
|
|
* -> working_state_after_reseed
|
|
* if required, then
|
|
* CTR_DRBG_Generate(working_state_after_reseed,
|
|
* requested_number_of_bits, additional_input)
|
|
* -> status, returned_bits, new_working_state
|
|
* with inputs
|
|
* ctx contains working_state
|
|
* requested_number_of_bits = 8 * output_len
|
|
* additional[:add_len] = additional_input
|
|
* and entropy_input comes from calling ctx->f_entropy
|
|
* and with outputs
|
|
* status = SUCCESS (this function does the reseed internally)
|
|
* returned_bits = output[:output_len]
|
|
* ctx contains new_working_state
|
|
*/
|
|
int mbedtls_ctr_drbg_random_with_add( void *p_rng,
|
|
unsigned char *output, size_t output_len,
|
|
const unsigned char *additional, size_t add_len )
|
|
{
|
|
int ret = 0;
|
|
mbedtls_ctr_drbg_context *ctx = (mbedtls_ctr_drbg_context *) p_rng;
|
|
unsigned char add_input[MBEDTLS_CTR_DRBG_SEEDLEN];
|
|
unsigned char *p = output;
|
|
unsigned char tmp[MBEDTLS_CTR_DRBG_BLOCKSIZE];
|
|
int i;
|
|
size_t use_len;
|
|
|
|
if( output_len > MBEDTLS_CTR_DRBG_MAX_REQUEST )
|
|
return( MBEDTLS_ERR_CTR_DRBG_REQUEST_TOO_BIG );
|
|
|
|
if( add_len > MBEDTLS_CTR_DRBG_MAX_INPUT )
|
|
return( MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG );
|
|
|
|
memset( add_input, 0, MBEDTLS_CTR_DRBG_SEEDLEN );
|
|
|
|
if( ctx->reseed_counter > ctx->reseed_interval ||
|
|
ctx->prediction_resistance )
|
|
{
|
|
if( ( ret = mbedtls_ctr_drbg_reseed( ctx, additional, add_len ) ) != 0 )
|
|
{
|
|
return( ret );
|
|
}
|
|
add_len = 0;
|
|
}
|
|
|
|
if( add_len > 0 )
|
|
{
|
|
if( ( ret = block_cipher_df( add_input, additional, add_len ) ) != 0 )
|
|
goto exit;
|
|
if( ( ret = ctr_drbg_update_internal( ctx, add_input ) ) != 0 )
|
|
goto exit;
|
|
}
|
|
|
|
while( output_len > 0 )
|
|
{
|
|
/*
|
|
* Increase counter
|
|
*/
|
|
for( i = MBEDTLS_CTR_DRBG_BLOCKSIZE; i > 0; i-- )
|
|
if( ++ctx->counter[i - 1] != 0 )
|
|
break;
|
|
|
|
/*
|
|
* Crypt counter block
|
|
*/
|
|
if( ( ret = mbedtls_aes_crypt_ecb( &ctx->aes_ctx, MBEDTLS_AES_ENCRYPT,
|
|
ctx->counter, tmp ) ) != 0 )
|
|
{
|
|
goto exit;
|
|
}
|
|
|
|
use_len = ( output_len > MBEDTLS_CTR_DRBG_BLOCKSIZE )
|
|
? MBEDTLS_CTR_DRBG_BLOCKSIZE : output_len;
|
|
/*
|
|
* Copy random block to destination
|
|
*/
|
|
memcpy( p, tmp, use_len );
|
|
p += use_len;
|
|
output_len -= use_len;
|
|
}
|
|
|
|
if( ( ret = ctr_drbg_update_internal( ctx, add_input ) ) != 0 )
|
|
goto exit;
|
|
|
|
ctx->reseed_counter++;
|
|
|
|
exit:
|
|
mbedtls_platform_zeroize( add_input, sizeof( add_input ) );
|
|
mbedtls_platform_zeroize( tmp, sizeof( tmp ) );
|
|
return( 0 );
|
|
}
|
|
|
|
int mbedtls_ctr_drbg_random( void *p_rng, unsigned char *output,
|
|
size_t output_len )
|
|
{
|
|
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
|
|
mbedtls_ctr_drbg_context *ctx = (mbedtls_ctr_drbg_context *) p_rng;
|
|
|
|
#if defined(MBEDTLS_THREADING_C)
|
|
if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 )
|
|
return( ret );
|
|
#endif
|
|
|
|
ret = mbedtls_ctr_drbg_random_with_add( ctx, output, output_len, NULL, 0 );
|
|
|
|
#if defined(MBEDTLS_THREADING_C)
|
|
if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 )
|
|
return( MBEDTLS_ERR_THREADING_MUTEX_ERROR );
|
|
#endif
|
|
|
|
return( ret );
|
|
}
|
|
|
|
#if defined(MBEDTLS_FS_IO)
|
|
int mbedtls_ctr_drbg_write_seed_file( mbedtls_ctr_drbg_context *ctx,
|
|
const char *path )
|
|
{
|
|
int ret = MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR;
|
|
FILE *f;
|
|
unsigned char buf[ MBEDTLS_CTR_DRBG_MAX_INPUT ];
|
|
|
|
if( ( f = fopen( path, "wb" ) ) == NULL )
|
|
return( MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR );
|
|
|
|
if( ( ret = mbedtls_ctr_drbg_random( ctx, buf,
|
|
MBEDTLS_CTR_DRBG_MAX_INPUT ) ) != 0 )
|
|
goto exit;
|
|
|
|
if( fwrite( buf, 1, MBEDTLS_CTR_DRBG_MAX_INPUT, f ) !=
|
|
MBEDTLS_CTR_DRBG_MAX_INPUT )
|
|
{
|
|
ret = MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR;
|
|
}
|
|
else
|
|
{
|
|
ret = 0;
|
|
}
|
|
|
|
exit:
|
|
mbedtls_platform_zeroize( buf, sizeof( buf ) );
|
|
|
|
fclose( f );
|
|
return( ret );
|
|
}
|
|
|
|
int mbedtls_ctr_drbg_update_seed_file( mbedtls_ctr_drbg_context *ctx,
|
|
const char *path )
|
|
{
|
|
int ret = 0;
|
|
FILE *f = NULL;
|
|
size_t n;
|
|
unsigned char buf[ MBEDTLS_CTR_DRBG_MAX_INPUT ];
|
|
unsigned char c;
|
|
|
|
if( ( f = fopen( path, "rb" ) ) == NULL )
|
|
return( MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR );
|
|
|
|
n = fread( buf, 1, sizeof( buf ), f );
|
|
if( fread( &c, 1, 1, f ) != 0 )
|
|
{
|
|
ret = MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG;
|
|
goto exit;
|
|
}
|
|
if( n == 0 || ferror( f ) )
|
|
{
|
|
ret = MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR;
|
|
goto exit;
|
|
}
|
|
fclose( f );
|
|
f = NULL;
|
|
|
|
ret = mbedtls_ctr_drbg_update_ret( ctx, buf, n );
|
|
|
|
exit:
|
|
mbedtls_platform_zeroize( buf, sizeof( buf ) );
|
|
if( f != NULL )
|
|
fclose( f );
|
|
if( ret != 0 )
|
|
return( ret );
|
|
return( mbedtls_ctr_drbg_write_seed_file( ctx, path ) );
|
|
}
|
|
#endif /* MBEDTLS_FS_IO */
|
|
|
|
#if defined(MBEDTLS_SELF_TEST)
|
|
|
|
static const unsigned char entropy_source_pr[96] =
|
|
{ 0xc1, 0x80, 0x81, 0xa6, 0x5d, 0x44, 0x02, 0x16,
|
|
0x19, 0xb3, 0xf1, 0x80, 0xb1, 0xc9, 0x20, 0x02,
|
|
0x6a, 0x54, 0x6f, 0x0c, 0x70, 0x81, 0x49, 0x8b,
|
|
0x6e, 0xa6, 0x62, 0x52, 0x6d, 0x51, 0xb1, 0xcb,
|
|
0x58, 0x3b, 0xfa, 0xd5, 0x37, 0x5f, 0xfb, 0xc9,
|
|
0xff, 0x46, 0xd2, 0x19, 0xc7, 0x22, 0x3e, 0x95,
|
|
0x45, 0x9d, 0x82, 0xe1, 0xe7, 0x22, 0x9f, 0x63,
|
|
0x31, 0x69, 0xd2, 0x6b, 0x57, 0x47, 0x4f, 0xa3,
|
|
0x37, 0xc9, 0x98, 0x1c, 0x0b, 0xfb, 0x91, 0x31,
|
|
0x4d, 0x55, 0xb9, 0xe9, 0x1c, 0x5a, 0x5e, 0xe4,
|
|
0x93, 0x92, 0xcf, 0xc5, 0x23, 0x12, 0xd5, 0x56,
|
|
0x2c, 0x4a, 0x6e, 0xff, 0xdc, 0x10, 0xd0, 0x68 };
|
|
|
|
static const unsigned char entropy_source_nopr[64] =
|
|
{ 0x5a, 0x19, 0x4d, 0x5e, 0x2b, 0x31, 0x58, 0x14,
|
|
0x54, 0xde, 0xf6, 0x75, 0xfb, 0x79, 0x58, 0xfe,
|
|
0xc7, 0xdb, 0x87, 0x3e, 0x56, 0x89, 0xfc, 0x9d,
|
|
0x03, 0x21, 0x7c, 0x68, 0xd8, 0x03, 0x38, 0x20,
|
|
0xf9, 0xe6, 0x5e, 0x04, 0xd8, 0x56, 0xf3, 0xa9,
|
|
0xc4, 0x4a, 0x4c, 0xbd, 0xc1, 0xd0, 0x08, 0x46,
|
|
0xf5, 0x98, 0x3d, 0x77, 0x1c, 0x1b, 0x13, 0x7e,
|
|
0x4e, 0x0f, 0x9d, 0x8e, 0xf4, 0x09, 0xf9, 0x2e };
|
|
|
|
static const unsigned char nonce_pers_pr[16] =
|
|
{ 0xd2, 0x54, 0xfc, 0xff, 0x02, 0x1e, 0x69, 0xd2,
|
|
0x29, 0xc9, 0xcf, 0xad, 0x85, 0xfa, 0x48, 0x6c };
|
|
|
|
static const unsigned char nonce_pers_nopr[16] =
|
|
{ 0x1b, 0x54, 0xb8, 0xff, 0x06, 0x42, 0xbf, 0xf5,
|
|
0x21, 0xf1, 0x5c, 0x1c, 0x0b, 0x66, 0x5f, 0x3f };
|
|
|
|
#if defined(MBEDTLS_CTR_DRBG_USE_128_BIT_KEY)
|
|
static const unsigned char result_pr[16] =
|
|
{ 0x95, 0x3c, 0xa5, 0xbd, 0x44, 0x1, 0x34, 0xb7,
|
|
0x13, 0x58, 0x3e, 0x6a, 0x6c, 0x7e, 0x88, 0x8a };
|
|
|
|
static const unsigned char result_nopr[16] =
|
|
{ 0x6c, 0x25, 0x27, 0x95, 0xa3, 0x62, 0xd6, 0xdb,
|
|
0x90, 0xfd, 0x69, 0xb5, 0x42, 0x9, 0x4b, 0x84 };
|
|
#else /* MBEDTLS_CTR_DRBG_USE_128_BIT_KEY */
|
|
static const unsigned char result_pr[16] =
|
|
{ 0x34, 0x01, 0x16, 0x56, 0xb4, 0x29, 0x00, 0x8f,
|
|
0x35, 0x63, 0xec, 0xb5, 0xf2, 0x59, 0x07, 0x23 };
|
|
|
|
static const unsigned char result_nopr[16] =
|
|
{ 0xa0, 0x54, 0x30, 0x3d, 0x8a, 0x7e, 0xa9, 0x88,
|
|
0x9d, 0x90, 0x3e, 0x07, 0x7c, 0x6f, 0x21, 0x8f };
|
|
#endif /* MBEDTLS_CTR_DRBG_USE_128_BIT_KEY */
|
|
|
|
static size_t test_offset;
|
|
static int ctr_drbg_self_test_entropy( void *data, unsigned char *buf,
|
|
size_t len )
|
|
{
|
|
const unsigned char *p = data;
|
|
memcpy( buf, p + test_offset, len );
|
|
test_offset += len;
|
|
return( 0 );
|
|
}
|
|
|
|
#define CHK( c ) if( (c) != 0 ) \
|
|
{ \
|
|
if( verbose != 0 ) \
|
|
mbedtls_printf( "failed\n" ); \
|
|
return( 1 ); \
|
|
}
|
|
|
|
/*
|
|
* Checkup routine
|
|
*/
|
|
int mbedtls_ctr_drbg_self_test( int verbose )
|
|
{
|
|
mbedtls_ctr_drbg_context ctx;
|
|
unsigned char buf[16];
|
|
|
|
mbedtls_ctr_drbg_init( &ctx );
|
|
|
|
/*
|
|
* Based on a NIST CTR_DRBG test vector (PR = True)
|
|
*/
|
|
if( verbose != 0 )
|
|
mbedtls_printf( " CTR_DRBG (PR = TRUE) : " );
|
|
|
|
test_offset = 0;
|
|
mbedtls_ctr_drbg_set_entropy_len( &ctx, 32 );
|
|
mbedtls_ctr_drbg_set_nonce_len( &ctx, 0 );
|
|
CHK( mbedtls_ctr_drbg_seed( &ctx,
|
|
ctr_drbg_self_test_entropy,
|
|
(void *) entropy_source_pr,
|
|
nonce_pers_pr, 16 ) );
|
|
mbedtls_ctr_drbg_set_prediction_resistance( &ctx, MBEDTLS_CTR_DRBG_PR_ON );
|
|
CHK( mbedtls_ctr_drbg_random( &ctx, buf, MBEDTLS_CTR_DRBG_BLOCKSIZE ) );
|
|
CHK( mbedtls_ctr_drbg_random( &ctx, buf, MBEDTLS_CTR_DRBG_BLOCKSIZE ) );
|
|
CHK( memcmp( buf, result_pr, MBEDTLS_CTR_DRBG_BLOCKSIZE ) );
|
|
|
|
mbedtls_ctr_drbg_free( &ctx );
|
|
|
|
if( verbose != 0 )
|
|
mbedtls_printf( "passed\n" );
|
|
|
|
/*
|
|
* Based on a NIST CTR_DRBG test vector (PR = FALSE)
|
|
*/
|
|
if( verbose != 0 )
|
|
mbedtls_printf( " CTR_DRBG (PR = FALSE): " );
|
|
|
|
mbedtls_ctr_drbg_init( &ctx );
|
|
|
|
test_offset = 0;
|
|
mbedtls_ctr_drbg_set_entropy_len( &ctx, 32 );
|
|
mbedtls_ctr_drbg_set_nonce_len( &ctx, 0 );
|
|
CHK( mbedtls_ctr_drbg_seed( &ctx,
|
|
ctr_drbg_self_test_entropy,
|
|
(void *) entropy_source_nopr,
|
|
nonce_pers_nopr, 16 ) );
|
|
CHK( mbedtls_ctr_drbg_random( &ctx, buf, 16 ) );
|
|
CHK( mbedtls_ctr_drbg_reseed( &ctx, NULL, 0 ) );
|
|
CHK( mbedtls_ctr_drbg_random( &ctx, buf, 16 ) );
|
|
CHK( memcmp( buf, result_nopr, 16 ) );
|
|
|
|
mbedtls_ctr_drbg_free( &ctx );
|
|
|
|
if( verbose != 0 )
|
|
mbedtls_printf( "passed\n" );
|
|
|
|
if( verbose != 0 )
|
|
mbedtls_printf( "\n" );
|
|
|
|
return( 0 );
|
|
}
|
|
#endif /* MBEDTLS_SELF_TEST */
|
|
|
|
#endif /* MBEDTLS_CTR_DRBG_C */
|