diff options
Diffstat (limited to 'library/ctr_drbg.c')
| -rw-r--r-- | library/ctr_drbg.c | 1016 |
1 files changed, 1016 insertions, 0 deletions
diff --git a/library/ctr_drbg.c b/library/ctr_drbg.c new file mode 100644 index 00000000000..66d9d28c589 --- /dev/null +++ b/library/ctr_drbg.c @@ -0,0 +1,1016 @@ +/* + * 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 §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 §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 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 §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 */ |