mirror of
https://github.com/trezor/trezor-firmware.git
synced 2024-12-21 05:48:23 +00:00
89 lines
3.2 KiB
C
89 lines
3.2 KiB
C
/**
|
|
* Copyright (c) 2023 Andrew R. Kozlik
|
|
*
|
|
* Permission is hereby granted, free of charge, to any person obtaining
|
|
* a copy of this software and associated documentation files (the "Software"),
|
|
* to deal in the Software without restriction, including without limitation
|
|
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
|
|
* and/or sell copies of the Software, and to permit persons to whom the
|
|
* Software is furnished to do so, subject to the following conditions:
|
|
*
|
|
* The above copyright notice and this permission notice shall be included
|
|
* in all copies or substantial portions of the Software.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
|
|
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
|
|
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES
|
|
* OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
|
|
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
|
|
* OTHER DEALINGS IN THE SOFTWARE.
|
|
*/
|
|
|
|
/*
|
|
* For a specification of TLS-PRF see
|
|
* https://datatracker.ietf.org/doc/html/rfc5246#section-5
|
|
*/
|
|
|
|
#include <string.h>
|
|
|
|
#include "hmac.h"
|
|
#include "memzero.h"
|
|
#include "sha2.h"
|
|
|
|
void tls_prf_sha256(const uint8_t *secret, size_t secret_len,
|
|
const uint8_t *label, size_t label_len, const uint8_t *seed,
|
|
size_t seed_len, uint8_t *output, size_t out_len) {
|
|
uint32_t idig[SHA256_DIGEST_LENGTH / sizeof(uint32_t)] = {0};
|
|
uint32_t odig[SHA256_DIGEST_LENGTH / sizeof(uint32_t)] = {0};
|
|
uint8_t a[SHA256_DIGEST_LENGTH] = {0};
|
|
uint8_t result[SHA256_DIGEST_LENGTH] = {0};
|
|
SHA256_CTX ctx = {0};
|
|
|
|
// Prepare inner and outer digest.
|
|
hmac_sha256_prepare(secret, secret_len, odig, idig);
|
|
|
|
// a = HMAC(secret, label + seed)
|
|
sha256_Init_ex(&ctx, idig, 8 * SHA256_BLOCK_LENGTH);
|
|
sha256_Update(&ctx, label, label_len);
|
|
sha256_Update(&ctx, seed, seed_len);
|
|
sha256_Final(&ctx, a);
|
|
sha256_Init_ex(&ctx, odig, 8 * SHA256_BLOCK_LENGTH);
|
|
sha256_Update(&ctx, a, SHA256_DIGEST_LENGTH);
|
|
sha256_Final(&ctx, a);
|
|
|
|
while (1) {
|
|
// result = HMAC(secret, a + label + seed)
|
|
sha256_Init_ex(&ctx, idig, 8 * SHA256_BLOCK_LENGTH);
|
|
sha256_Update(&ctx, a, SHA256_DIGEST_LENGTH);
|
|
sha256_Update(&ctx, label, label_len);
|
|
sha256_Update(&ctx, seed, seed_len);
|
|
sha256_Final(&ctx, result);
|
|
sha256_Init_ex(&ctx, odig, 8 * SHA256_BLOCK_LENGTH);
|
|
sha256_Update(&ctx, result, SHA256_DIGEST_LENGTH);
|
|
sha256_Final(&ctx, result);
|
|
|
|
if (out_len <= SHA256_DIGEST_LENGTH) {
|
|
break;
|
|
}
|
|
|
|
memcpy(output, result, SHA256_DIGEST_LENGTH);
|
|
output += SHA256_DIGEST_LENGTH;
|
|
out_len -= SHA256_DIGEST_LENGTH;
|
|
|
|
// a = HMAC(secret, a)
|
|
sha256_Init_ex(&ctx, idig, 8 * SHA256_BLOCK_LENGTH);
|
|
sha256_Update(&ctx, a, SHA256_DIGEST_LENGTH);
|
|
sha256_Final(&ctx, a);
|
|
sha256_Init_ex(&ctx, odig, 8 * SHA256_BLOCK_LENGTH);
|
|
sha256_Update(&ctx, a, SHA256_DIGEST_LENGTH);
|
|
sha256_Final(&ctx, a);
|
|
}
|
|
|
|
memcpy(output, result, out_len);
|
|
memzero(idig, sizeof(idig));
|
|
memzero(odig, sizeof(odig));
|
|
memzero(a, sizeof(a));
|
|
memzero(result, sizeof(result));
|
|
}
|