| /* |
| * 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 |
| |
| #include "mbedtls/platform.h" |
| |
| /* |
| * CTR_DRBG context initialization |
| */ |
| void mbedtls_ctr_drbg_init(mbedtls_ctr_drbg_context *ctx) |
| { |
| memset(ctx, 0, sizeof(mbedtls_ctr_drbg_context)); |
| mbedtls_aes_init(&ctx->aes_ctx); |
| /* 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 |
| 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; |
| } |
| |
| 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; |
| 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; |
| 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 ((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) { |
| 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 ((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(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 §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 §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 ((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 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 */ |
