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mbedtls/library/ctr_drbg.c
Gavin Acquroff 6aceb51e43 Support set *_drbg reseed interval before seed 
mbedtls_ctr_drbg_set_reseed_interval() and
mbedtls_hmac_drbg_set_reseed_interval() can now be called before
their seed functions and the reseed_interval value will persist.
Previously it would be overwritten with the default value.

*_drbg_reseed_interval is now set in init() and free().

mbedtls_ctr_drbg_free() and mbedtls_hmac_drbg_free() now
reset the drbg context to the state immediately after init().

Tests:
- Added test to check that DRBG reseeds when reseed_counter
reaches reseed_interval, if reseed_interval set before seed
and reseed_interval is less than MBEDTLS_CTR_DRBG_RESEED_INTERVAL.

Signed-off-by: gacquroff <gavina352@gmail.com>
2020-11-25 14:25:56 -08:00

819 lines
26 KiB
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/*
* CTR_DRBG implementation based on AES-256 (NIST SP 800-90)
*
* 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.
*/
/*
* The NIST SP 800-90 DRBGs are described in the following publication.
*
* http://csrc.nist.gov/publications/nistpubs/800-90/SP800-90revised_March2007.pdf
*/
#include "common.h"
#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;
ctx->reseed_interval = MBEDTLS_CTR_DRBG_RESEED_INTERVAL;
#if defined(MBEDTLS_THREADING_C)
mbedtls_mutex_init( &ctx->mutex );
#endif
}
/*
* This function resets CTR_DRBG context to the state immediately
* after initial call of mbedtls_ctr_drbg_init().
*/
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 ) );
ctx->reseed_interval = MBEDTLS_CTR_DRBG_RESEED_INTERVAL;
ctx->reseed_counter = -1;
#if defined(MBEDTLS_THREADING_C)
mbedtls_mutex_init( &ctx->mutex );
#endif
}
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 &sect;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 &sect;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 &sect;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 &sect;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 ) );
/* 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 &sect;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( ret );
}
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 */
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