diff options
Diffstat (limited to 'src/libs/mynewt-nimble/ext/tinycrypt/src/hmac.c')
| -rw-r--r-- | src/libs/mynewt-nimble/ext/tinycrypt/src/hmac.c | 148 |
1 files changed, 148 insertions, 0 deletions
diff --git a/src/libs/mynewt-nimble/ext/tinycrypt/src/hmac.c b/src/libs/mynewt-nimble/ext/tinycrypt/src/hmac.c new file mode 100644 index 00000000..89878cec --- /dev/null +++ b/src/libs/mynewt-nimble/ext/tinycrypt/src/hmac.c @@ -0,0 +1,148 @@ +/* hmac.c - TinyCrypt implementation of the HMAC algorithm */ + +/* + * Copyright (C) 2017 by Intel Corporation, All Rights Reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * - Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * + * - Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * - Neither the name of Intel Corporation nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +#include <tinycrypt/hmac.h> +#include <tinycrypt/constants.h> +#include <tinycrypt/utils.h> + +static void rekey(uint8_t *key, const uint8_t *new_key, unsigned int key_size) +{ + const uint8_t inner_pad = (uint8_t) 0x36; + const uint8_t outer_pad = (uint8_t) 0x5c; + unsigned int i; + + for (i = 0; i < key_size; ++i) { + key[i] = inner_pad ^ new_key[i]; + key[i + TC_SHA256_BLOCK_SIZE] = outer_pad ^ new_key[i]; + } + for (; i < TC_SHA256_BLOCK_SIZE; ++i) { + key[i] = inner_pad; key[i + TC_SHA256_BLOCK_SIZE] = outer_pad; + } +} + +int tc_hmac_set_key(TCHmacState_t ctx, const uint8_t *key, + unsigned int key_size) +{ + + /* input sanity check: */ + if (ctx == (TCHmacState_t) 0 || + key == (const uint8_t *) 0 || + key_size == 0) { + return TC_CRYPTO_FAIL; + } + + const uint8_t dummy_key[key_size]; + struct tc_hmac_state_struct dummy_state; + + if (key_size <= TC_SHA256_BLOCK_SIZE) { + /* + * The next three lines consist of dummy calls just to avoid + * certain timing attacks. Without these dummy calls, + * adversaries would be able to learn whether the key_size is + * greater than TC_SHA256_BLOCK_SIZE by measuring the time + * consumed in this process. + */ + (void)tc_sha256_init(&dummy_state.hash_state); + (void)tc_sha256_update(&dummy_state.hash_state, + dummy_key, + key_size); + (void)tc_sha256_final(&dummy_state.key[TC_SHA256_DIGEST_SIZE], + &dummy_state.hash_state); + + /* Actual code for when key_size <= TC_SHA256_BLOCK_SIZE: */ + rekey(ctx->key, key, key_size); + } else { + (void)tc_sha256_init(&ctx->hash_state); + (void)tc_sha256_update(&ctx->hash_state, key, key_size); + (void)tc_sha256_final(&ctx->key[TC_SHA256_DIGEST_SIZE], + &ctx->hash_state); + rekey(ctx->key, + &ctx->key[TC_SHA256_DIGEST_SIZE], + TC_SHA256_DIGEST_SIZE); + } + + return TC_CRYPTO_SUCCESS; +} + +int tc_hmac_init(TCHmacState_t ctx) +{ + + /* input sanity check: */ + if (ctx == (TCHmacState_t) 0) { + return TC_CRYPTO_FAIL; + } + + (void) tc_sha256_init(&ctx->hash_state); + (void) tc_sha256_update(&ctx->hash_state, ctx->key, TC_SHA256_BLOCK_SIZE); + + return TC_CRYPTO_SUCCESS; +} + +int tc_hmac_update(TCHmacState_t ctx, + const void *data, + unsigned int data_length) +{ + + /* input sanity check: */ + if (ctx == (TCHmacState_t) 0) { + return TC_CRYPTO_FAIL; + } + + (void)tc_sha256_update(&ctx->hash_state, data, data_length); + + return TC_CRYPTO_SUCCESS; +} + +int tc_hmac_final(uint8_t *tag, unsigned int taglen, TCHmacState_t ctx) +{ + + /* input sanity check: */ + if (tag == (uint8_t *) 0 || + taglen != TC_SHA256_DIGEST_SIZE || + ctx == (TCHmacState_t) 0) { + return TC_CRYPTO_FAIL; + } + + (void) tc_sha256_final(tag, &ctx->hash_state); + + (void)tc_sha256_init(&ctx->hash_state); + (void)tc_sha256_update(&ctx->hash_state, + &ctx->key[TC_SHA256_BLOCK_SIZE], + TC_SHA256_BLOCK_SIZE); + (void)tc_sha256_update(&ctx->hash_state, tag, TC_SHA256_DIGEST_SIZE); + (void)tc_sha256_final(tag, &ctx->hash_state); + + /* destroy the current state */ + _set(ctx, 0, sizeof(*ctx)); + + return TC_CRYPTO_SUCCESS; +} |