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mbedtls/library/ctr_drbg.c
Dave Rodgman 7e5b7f91ca Fix error in ctr_drbg 
Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
2024-01-16 17:28:25 +00:00

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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 OR GPL-2.0-or-later
*/
/*
* The NIST SP 800-90 DRBGs are described in the following publication.
*
* https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-90r.pdf
*/
#include "common.h"
#if defined(MBEDTLS_CTR_DRBG_C)
#include "ctr.h"
#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
/* Using error translation functions from PSA to MbedTLS */
#if !defined(MBEDTLS_AES_C)
#include "psa_util_internal.h"
#endif
#include "mbedtls/platform.h"
#if !defined(MBEDTLS_AES_C)
static psa_status_t ctr_drbg_setup_psa_context(mbedtls_ctr_drbg_psa_context *psa_ctx,
unsigned char *key, size_t key_len)
{
psa_key_attributes_t key_attr = PSA_KEY_ATTRIBUTES_INIT;
psa_status_t status;
psa_set_key_usage_flags(&key_attr, PSA_KEY_USAGE_ENCRYPT);
psa_set_key_algorithm(&key_attr, PSA_ALG_ECB_NO_PADDING);
psa_set_key_type(&key_attr, PSA_KEY_TYPE_AES);
status = psa_import_key(&key_attr, key, key_len, &psa_ctx->key_id);
if (status != PSA_SUCCESS) {
goto exit;
}
status = psa_cipher_encrypt_setup(&psa_ctx->operation, psa_ctx->key_id, PSA_ALG_ECB_NO_PADDING);
if (status != PSA_SUCCESS) {
goto exit;
}
exit:
psa_reset_key_attributes(&key_attr);
return status;
}
static void ctr_drbg_destroy_psa_contex(mbedtls_ctr_drbg_psa_context *psa_ctx)
{
psa_cipher_abort(&psa_ctx->operation);
psa_destroy_key(psa_ctx->key_id);
psa_ctx->operation = psa_cipher_operation_init();
psa_ctx->key_id = MBEDTLS_SVC_KEY_ID_INIT;
}
#endif
/*
* CTR_DRBG context initialization
*/
void mbedtls_ctr_drbg_init(mbedtls_ctr_drbg_context *ctx)
{
memset(ctx, 0, sizeof(mbedtls_ctr_drbg_context));
#if defined(MBEDTLS_AES_C)
mbedtls_aes_init(&ctx->aes_ctx);
#else
ctx->psa_ctx.key_id = MBEDTLS_SVC_KEY_ID_INIT;
ctx->psa_ctx.operation = psa_cipher_operation_init();
#endif
/* 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;
}
/*
* 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)
/* The mutex is initialized iff f_entropy is set. */
if (ctx->f_entropy != NULL) {
mbedtls_mutex_free(&ctx->mutex);
}
#endif
#if defined(MBEDTLS_AES_C)
mbedtls_aes_free(&ctx->aes_ctx);
#else
ctr_drbg_destroy_psa_contex(&ctx->psa_ctx);
#endif
mbedtls_platform_zeroize(ctx, sizeof(mbedtls_ctr_drbg_context));
ctx->reseed_interval = MBEDTLS_CTR_DRBG_RESEED_INTERVAL;
ctx->reseed_counter = -1;
}
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;
}
/* 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;
}
/* 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;
int ret = 0;
#if defined(MBEDTLS_AES_C)
mbedtls_aes_context aes_ctx;
#else
psa_status_t status;
size_t tmp_len;
mbedtls_ctr_drbg_psa_context psa_ctx;
psa_ctx.key_id = MBEDTLS_SVC_KEY_ID_INIT;
psa_ctx.operation = psa_cipher_operation_init();
#endif
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);
/*
* 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;
MBEDTLS_PUT_UINT32_BE(data_len, p, 0);
p += 4 + 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 defined(MBEDTLS_AES_C)
mbedtls_aes_init(&aes_ctx);
if ((ret = mbedtls_aes_setkey_enc(&aes_ctx, key,
MBEDTLS_CTR_DRBG_KEYBITS)) != 0) {
goto exit;
}
#else
status = ctr_drbg_setup_psa_context(&psa_ctx, key, sizeof(key));
if (status != PSA_SUCCESS) {
ret = psa_generic_status_to_mbedtls(status);
goto exit;
}
#endif
/*
* 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) {
mbedtls_xor(chain, chain, p, MBEDTLS_CTR_DRBG_BLOCKSIZE);
p += MBEDTLS_CTR_DRBG_BLOCKSIZE;
use_len -= (use_len >= MBEDTLS_CTR_DRBG_BLOCKSIZE) ?
MBEDTLS_CTR_DRBG_BLOCKSIZE : use_len;
#if defined(MBEDTLS_AES_C)
if ((ret = mbedtls_aes_crypt_ecb(&aes_ctx, MBEDTLS_AES_ENCRYPT,
chain, chain)) != 0) {
goto exit;
}
#else
status = psa_cipher_update(&psa_ctx.operation, chain, MBEDTLS_CTR_DRBG_BLOCKSIZE,
chain, MBEDTLS_CTR_DRBG_BLOCKSIZE, &tmp_len);
if (status != PSA_SUCCESS) {
ret = psa_generic_status_to_mbedtls(status);
goto exit;
}
#endif
}
memcpy(tmp + j, chain, MBEDTLS_CTR_DRBG_BLOCKSIZE);
/*
* Update IV
*/
buf[3]++;
}
/*
* Do final encryption with reduced data
*/
#if defined(MBEDTLS_AES_C)
if ((ret = mbedtls_aes_setkey_enc(&aes_ctx, tmp,
MBEDTLS_CTR_DRBG_KEYBITS)) != 0) {
goto exit;
}
#else
ctr_drbg_destroy_psa_contex(&psa_ctx);
status = ctr_drbg_setup_psa_context(&psa_ctx, tmp, MBEDTLS_CTR_DRBG_KEYSIZE);
if (status != PSA_SUCCESS) {
ret = psa_generic_status_to_mbedtls(status);
goto exit;
}
#endif
iv = tmp + MBEDTLS_CTR_DRBG_KEYSIZE;
p = output;
for (j = 0; j < MBEDTLS_CTR_DRBG_SEEDLEN; j += MBEDTLS_CTR_DRBG_BLOCKSIZE) {
#if defined(MBEDTLS_AES_C)
if ((ret = mbedtls_aes_crypt_ecb(&aes_ctx, MBEDTLS_AES_ENCRYPT,
iv, iv)) != 0) {
goto exit;
}
#else
status = psa_cipher_update(&psa_ctx.operation, iv, MBEDTLS_CTR_DRBG_BLOCKSIZE,
iv, MBEDTLS_CTR_DRBG_BLOCKSIZE, &tmp_len);
if (status != PSA_SUCCESS) {
ret = psa_generic_status_to_mbedtls(status);
goto exit;
}
#endif
memcpy(p, iv, MBEDTLS_CTR_DRBG_BLOCKSIZE);
p += MBEDTLS_CTR_DRBG_BLOCKSIZE;
}
exit:
#if defined(MBEDTLS_AES_C)
mbedtls_aes_free(&aes_ctx);
#else
ctr_drbg_destroy_psa_contex(&psa_ctx);
#endif
/*
* 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 j;
int ret = 0;
#if !defined(MBEDTLS_AES_C)
psa_status_t status;
size_t tmp_len;
#endif
memset(tmp, 0, MBEDTLS_CTR_DRBG_SEEDLEN);
for (j = 0; j < MBEDTLS_CTR_DRBG_SEEDLEN; j += MBEDTLS_CTR_DRBG_BLOCKSIZE) {
/*
* Increase counter
*/
mbedtls_ctr_increment_counter(ctx->counter);
/*
* Crypt counter block
*/
#if defined(MBEDTLS_AES_C)
if ((ret = mbedtls_aes_crypt_ecb(&ctx->aes_ctx, MBEDTLS_AES_ENCRYPT,
ctx->counter, p)) != 0) {
goto exit;
}
#else
status = psa_cipher_update(&ctx->psa_ctx.operation, ctx->counter, sizeof(ctx->counter),
p, MBEDTLS_CTR_DRBG_BLOCKSIZE, &tmp_len);
if (status != PSA_SUCCESS) {
ret = psa_generic_status_to_mbedtls(status);
goto exit;
}
#endif
p += MBEDTLS_CTR_DRBG_BLOCKSIZE;
}
mbedtls_xor(tmp, tmp, data, MBEDTLS_CTR_DRBG_SEEDLEN);
/*
* Update key and counter
*/
#if defined(MBEDTLS_AES_C)
if ((ret = mbedtls_aes_setkey_enc(&ctx->aes_ctx, tmp,
MBEDTLS_CTR_DRBG_KEYBITS)) != 0) {
goto exit;
}
#else
ctr_drbg_destroy_psa_contex(&ctx->psa_ctx);
status = ctr_drbg_setup_psa_context(&ctx->psa_ctx, tmp, MBEDTLS_CTR_DRBG_KEYSIZE);
if (status != PSA_SUCCESS) {
ret = psa_generic_status_to_mbedtls(status);
goto exit;
}
#endif
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(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;
}
/* 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 + seedlen, 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);
/* The mutex is initialized iff f_entropy is set. */
#if defined(MBEDTLS_THREADING_C)
mbedtls_mutex_init(&ctx->mutex);
#endif
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 defined(MBEDTLS_AES_C)
if ((ret = mbedtls_aes_setkey_enc(&ctx->aes_ctx, key,
MBEDTLS_CTR_DRBG_KEYBITS)) != 0) {
return ret;
}
#else
psa_status_t status;
status = ctr_drbg_setup_psa_context(&ctx->psa_ctx, key, MBEDTLS_CTR_DRBG_KEYSIZE);
if (status != PSA_SUCCESS) {
ret = psa_generic_status_to_mbedtls(status);
return status;
}
#endif
/* 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 *p = output;
struct {
unsigned char add_input[MBEDTLS_CTR_DRBG_SEEDLEN];
unsigned char tmp[MBEDTLS_CTR_DRBG_BLOCKSIZE];
} locals;
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(locals.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(locals.add_input, additional, add_len)) != 0) {
goto exit;
}
if ((ret = ctr_drbg_update_internal(ctx, locals.add_input)) != 0) {
goto exit;
}
}
while (output_len > 0) {
/*
* Increase counter (treat it as a 128-bit big-endian integer).
*/
mbedtls_ctr_increment_counter(ctx->counter);
/*
* Crypt counter block
*/
#if defined(MBEDTLS_AES_C)
if ((ret = mbedtls_aes_crypt_ecb(&ctx->aes_ctx, MBEDTLS_AES_ENCRYPT,
ctx->counter, locals.tmp)) != 0) {
goto exit;
}
#else
psa_status_t status;
size_t tmp_len;
status = psa_cipher_update(&ctx->psa_ctx.operation, ctx->counter, sizeof(ctx->counter),
locals.tmp, MBEDTLS_CTR_DRBG_BLOCKSIZE, &tmp_len);
if (status != PSA_SUCCESS) {
ret = psa_generic_status_to_mbedtls(status);
goto exit;
}
#endif
use_len = (output_len > MBEDTLS_CTR_DRBG_BLOCKSIZE)
? MBEDTLS_CTR_DRBG_BLOCKSIZE : output_len;
/*
* Copy random block to destination
*/
memcpy(p, locals.tmp, use_len);
p += use_len;
output_len -= use_len;
}
if ((ret = ctr_drbg_update_internal(ctx, locals.add_input)) != 0) {
goto exit;
}
ctx->reseed_counter++;
exit:
mbedtls_platform_zeroize(&locals, sizeof(locals));
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;
}
/* Ensure no stdio buffering of secrets, as such buffers cannot be wiped. */
mbedtls_setbuf(f, NULL);
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;
}
/* Ensure no stdio buffering of secrets, as such buffers cannot be wiped. */
mbedtls_setbuf(f, NULL);
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(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)
/* The CTR_DRBG NIST test vectors used here are available at
* https://csrc.nist.gov/CSRC/media/Projects/Cryptographic-Algorithm-Validation-Program/documents/drbg/drbgtestvectors.zip
*
* The parameters used to derive the test data are:
*
* [AES-128 use df]
* [PredictionResistance = True/False]
* [EntropyInputLen = 128]
* [NonceLen = 64]
* [PersonalizationStringLen = 128]
* [AdditionalInputLen = 0]
* [ReturnedBitsLen = 512]
*
* [AES-256 use df]
* [PredictionResistance = True/False]
* [EntropyInputLen = 256]
* [NonceLen = 128]
* [PersonalizationStringLen = 256]
* [AdditionalInputLen = 0]
* [ReturnedBitsLen = 512]
*
*/
#if defined(MBEDTLS_CTR_DRBG_USE_128_BIT_KEY)
static const unsigned char entropy_source_pr[] =
{ 0x04, 0xd9, 0x49, 0xa6, 0xdc, 0xe8, 0x6e, 0xbb,
0xf1, 0x08, 0x77, 0x2b, 0x9e, 0x08, 0xca, 0x92,
0x65, 0x16, 0xda, 0x99, 0xa2, 0x59, 0xf3, 0xe8,
0x38, 0x7e, 0x3f, 0x6b, 0x51, 0x70, 0x7b, 0x20,
0xec, 0x53, 0xd0, 0x66, 0xc3, 0x0f, 0xe3, 0xb0,
0xe0, 0x86, 0xa6, 0xaa, 0x5f, 0x72, 0x2f, 0xad,
0xf7, 0xef, 0x06, 0xb8, 0xd6, 0x9c, 0x9d, 0xe8 };
static const unsigned char entropy_source_nopr[] =
{ 0x07, 0x0d, 0x59, 0x63, 0x98, 0x73, 0xa5, 0x45,
0x27, 0x38, 0x22, 0x7b, 0x76, 0x85, 0xd1, 0xa9,
0x74, 0x18, 0x1f, 0x3c, 0x22, 0xf6, 0x49, 0x20,
0x4a, 0x47, 0xc2, 0xf3, 0x85, 0x16, 0xb4, 0x6f,
0x00, 0x2e, 0x71, 0xda, 0xed, 0x16, 0x9b, 0x5c };
static const unsigned char pers_pr[] =
{ 0xbf, 0xa4, 0x9a, 0x8f, 0x7b, 0xd8, 0xb1, 0x7a,
0x9d, 0xfa, 0x45, 0xed, 0x21, 0x52, 0xb3, 0xad };
static const unsigned char pers_nopr[] =
{ 0x4e, 0x61, 0x79, 0xd4, 0xc2, 0x72, 0xa1, 0x4c,
0xf1, 0x3d, 0xf6, 0x5e, 0xa3, 0xa6, 0xe5, 0x0f };
static const unsigned char result_pr[] =
{ 0xc9, 0x0a, 0xaf, 0x85, 0x89, 0x71, 0x44, 0x66,
0x4f, 0x25, 0x0b, 0x2b, 0xde, 0xd8, 0xfa, 0xff,
0x52, 0x5a, 0x1b, 0x32, 0x5e, 0x41, 0x7a, 0x10,
0x1f, 0xef, 0x1e, 0x62, 0x23, 0xe9, 0x20, 0x30,
0xc9, 0x0d, 0xad, 0x69, 0xb4, 0x9c, 0x5b, 0xf4,
0x87, 0x42, 0xd5, 0xae, 0x5e, 0x5e, 0x43, 0xcc,
0xd9, 0xfd, 0x0b, 0x93, 0x4a, 0xe3, 0xd4, 0x06,
0x37, 0x36, 0x0f, 0x3f, 0x72, 0x82, 0x0c, 0xcf };
static const unsigned char result_nopr[] =
{ 0x31, 0xc9, 0x91, 0x09, 0xf8, 0xc5, 0x10, 0x13,
0x3c, 0xd3, 0x96, 0xf9, 0xbc, 0x2c, 0x12, 0xc0,
0x7c, 0xc1, 0x61, 0x5f, 0xa3, 0x09, 0x99, 0xaf,
0xd7, 0xf2, 0x36, 0xfd, 0x40, 0x1a, 0x8b, 0xf2,
0x33, 0x38, 0xee, 0x1d, 0x03, 0x5f, 0x83, 0xb7,
0xa2, 0x53, 0xdc, 0xee, 0x18, 0xfc, 0xa7, 0xf2,
0xee, 0x96, 0xc6, 0xc2, 0xcd, 0x0c, 0xff, 0x02,
0x76, 0x70, 0x69, 0xaa, 0x69, 0xd1, 0x3b, 0xe8 };
#else /* MBEDTLS_CTR_DRBG_USE_128_BIT_KEY */
static const unsigned char entropy_source_pr[] =
{ 0xca, 0x58, 0xfd, 0xf2, 0xb9, 0x77, 0xcb, 0x49,
0xd4, 0xe0, 0x5b, 0xe2, 0x39, 0x50, 0xd9, 0x8a,
0x6a, 0xb3, 0xc5, 0x2f, 0xdf, 0x74, 0xd5, 0x85,
0x8f, 0xd1, 0xba, 0x64, 0x54, 0x7b, 0xdb, 0x1e,
0xc5, 0xea, 0x24, 0xc0, 0xfa, 0x0c, 0x90, 0x15,
0x09, 0x20, 0x92, 0x42, 0x32, 0x36, 0x45, 0x45,
0x7d, 0x20, 0x76, 0x6b, 0xcf, 0xa2, 0x15, 0xc8,
0x2f, 0x9f, 0xbc, 0x88, 0x3f, 0x80, 0xd1, 0x2c,
0xb7, 0x16, 0xd1, 0x80, 0x9e, 0xe1, 0xc9, 0xb3,
0x88, 0x1b, 0x21, 0x45, 0xef, 0xa1, 0x7f, 0xce,
0xc8, 0x92, 0x35, 0x55, 0x2a, 0xd9, 0x1d, 0x8e,
0x12, 0x38, 0xac, 0x01, 0x4e, 0x38, 0x18, 0x76,
0x9c, 0xf2, 0xb6, 0xd4, 0x13, 0xb6, 0x2c, 0x77,
0xc0, 0xe7, 0xe6, 0x0c, 0x47, 0x44, 0x95, 0xbe };
static const unsigned char entropy_source_nopr[] =
{ 0x4c, 0xfb, 0x21, 0x86, 0x73, 0x34, 0x6d, 0x9d,
0x50, 0xc9, 0x22, 0xe4, 0x9b, 0x0d, 0xfc, 0xd0,
0x90, 0xad, 0xf0, 0x4f, 0x5c, 0x3b, 0xa4, 0x73,
0x27, 0xdf, 0xcd, 0x6f, 0xa6, 0x3a, 0x78, 0x5c,
0x01, 0x69, 0x62, 0xa7, 0xfd, 0x27, 0x87, 0xa2,
0x4b, 0xf6, 0xbe, 0x47, 0xef, 0x37, 0x83, 0xf1,
0xb7, 0xec, 0x46, 0x07, 0x23, 0x63, 0x83, 0x4a,
0x1b, 0x01, 0x33, 0xf2, 0xc2, 0x38, 0x91, 0xdb,
0x4f, 0x11, 0xa6, 0x86, 0x51, 0xf2, 0x3e, 0x3a,
0x8b, 0x1f, 0xdc, 0x03, 0xb1, 0x92, 0xc7, 0xe7 };
static const unsigned char pers_pr[] =
{ 0x5a, 0x70, 0x95, 0xe9, 0x81, 0x40, 0x52, 0x33,
0x91, 0x53, 0x7e, 0x75, 0xd6, 0x19, 0x9d, 0x1e,
0xad, 0x0d, 0xc6, 0xa7, 0xde, 0x6c, 0x1f, 0xe0,
0xea, 0x18, 0x33, 0xa8, 0x7e, 0x06, 0x20, 0xe9 };
static const unsigned char pers_nopr[] =
{ 0x88, 0xee, 0xb8, 0xe0, 0xe8, 0x3b, 0xf3, 0x29,
0x4b, 0xda, 0xcd, 0x60, 0x99, 0xeb, 0xe4, 0xbf,
0x55, 0xec, 0xd9, 0x11, 0x3f, 0x71, 0xe5, 0xeb,
0xcb, 0x45, 0x75, 0xf3, 0xd6, 0xa6, 0x8a, 0x6b };
static const unsigned char result_pr[] =
{ 0xce, 0x2f, 0xdb, 0xb6, 0xd9, 0xb7, 0x39, 0x85,
0x04, 0xc5, 0xc0, 0x42, 0xc2, 0x31, 0xc6, 0x1d,
0x9b, 0x5a, 0x59, 0xf8, 0x7e, 0x0d, 0xcc, 0x62,
0x7b, 0x65, 0x11, 0x55, 0x10, 0xeb, 0x9e, 0x3d,
0xa4, 0xfb, 0x1c, 0x6a, 0x18, 0xc0, 0x74, 0xdb,
0xdd, 0xe7, 0x02, 0x23, 0x63, 0x21, 0xd0, 0x39,
0xf9, 0xa7, 0xc4, 0x52, 0x84, 0x3b, 0x49, 0x40,
0x72, 0x2b, 0xb0, 0x6c, 0x9c, 0xdb, 0xc3, 0x43 };
static const unsigned char result_nopr[] =
{ 0xa5, 0x51, 0x80, 0xa1, 0x90, 0xbe, 0xf3, 0xad,
0xaf, 0x28, 0xf6, 0xb7, 0x95, 0xe9, 0xf1, 0xf3,
0xd6, 0xdf, 0xa1, 0xb2, 0x7d, 0xd0, 0x46, 0x7b,
0x0c, 0x75, 0xf5, 0xfa, 0x93, 0x1e, 0x97, 0x14,
0x75, 0xb2, 0x7c, 0xae, 0x03, 0xa2, 0x96, 0x54,
0xe2, 0xf4, 0x09, 0x66, 0xea, 0x33, 0x64, 0x30,
0x40, 0xd1, 0x40, 0x0f, 0xe6, 0x77, 0x87, 0x3a,
0xf8, 0x09, 0x7c, 0x1f, 0xe9, 0xf0, 0x02, 0x98 };
#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; \
}
#define SELF_TEST_OUTPUT_DISCARD_LENGTH 64
/*
* Checkup routine
*/
int mbedtls_ctr_drbg_self_test(int verbose)
{
mbedtls_ctr_drbg_context ctx;
unsigned char buf[sizeof(result_pr)];
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, MBEDTLS_CTR_DRBG_KEYSIZE);
mbedtls_ctr_drbg_set_nonce_len(&ctx, MBEDTLS_CTR_DRBG_KEYSIZE / 2);
CHK(mbedtls_ctr_drbg_seed(&ctx,
ctr_drbg_self_test_entropy,
(void *) entropy_source_pr,
pers_pr, MBEDTLS_CTR_DRBG_KEYSIZE));
mbedtls_ctr_drbg_set_prediction_resistance(&ctx, MBEDTLS_CTR_DRBG_PR_ON);
CHK(mbedtls_ctr_drbg_random(&ctx, buf, SELF_TEST_OUTPUT_DISCARD_LENGTH));
CHK(mbedtls_ctr_drbg_random(&ctx, buf, sizeof(result_pr)));
CHK(memcmp(buf, result_pr, sizeof(result_pr)));
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, MBEDTLS_CTR_DRBG_KEYSIZE);
mbedtls_ctr_drbg_set_nonce_len(&ctx, MBEDTLS_CTR_DRBG_KEYSIZE / 2);
CHK(mbedtls_ctr_drbg_seed(&ctx,
ctr_drbg_self_test_entropy,
(void *) entropy_source_nopr,
pers_nopr, MBEDTLS_CTR_DRBG_KEYSIZE));
CHK(mbedtls_ctr_drbg_reseed(&ctx, NULL, 0));
CHK(mbedtls_ctr_drbg_random(&ctx, buf, SELF_TEST_OUTPUT_DISCARD_LENGTH));
CHK(mbedtls_ctr_drbg_random(&ctx, buf, sizeof(result_nopr)));
CHK(memcmp(buf, result_nopr, sizeof(result_nopr)));
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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