mirror of
https://github.com/tillitis/tillitis-key1.git
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67 lines
1.5 KiB
C
67 lines
1.5 KiB
C
// Copyright (C) 2024 - Tillitis AB
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// SPDX-License-Identifier: GPL-2.0-only
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#include "auth_app.h"
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#include "../tk1_mem.h"
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#include "blake2s/blake2s.h"
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#include "lib.h"
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#include "partition_table.h"
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#include "rng.h"
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#include <stdbool.h>
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#include <stdint.h>
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static volatile uint32_t *cdi = (volatile uint32_t *)TK1_MMIO_TK1_CDI_FIRST;
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static void calculate_auth_digest(uint8_t *nonce, uint8_t *auth_digest)
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{
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/* TODO: Check so the CDI is non-zero? */
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blake2s_ctx ctx = {0};
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blake2s_init(&ctx, 16, NULL,
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0); // Generate a 16 byte authentication digest
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blake2s_update(&ctx, (const void *)cdi, 32);
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blake2s_update(&ctx, nonce, 16);
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blake2s_final(&ctx, auth_digest);
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}
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/* Generates a 16 byte nonce */
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static void generate_nonce(uint32_t *nonce)
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{
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for (uint8_t i = 0; i < 4; i++) {
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nonce[i] = rng_get_word();
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}
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return;
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}
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/* Returns the authentication digest and random nonce. Requites that the CDI is
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* already calculated and stored */
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void auth_app_create(auth_metadata_t *auth_table)
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{
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uint8_t nonce[16];
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uint8_t auth_digest[16];
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generate_nonce((uint32_t *)nonce);
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calculate_auth_digest(nonce, auth_digest);
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memcpy_s(auth_table->authentication_digest, 16, auth_digest, 16);
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memcpy_s(auth_table->nonce, 16, nonce, 16);
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return;
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}
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bool auth_app_authenticate(auth_metadata_t *auth_table)
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{
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uint8_t auth_digest[16];
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calculate_auth_digest(auth_table->nonce, auth_digest);
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if (memeq(auth_digest, auth_table->authentication_digest, 16)) {
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return true;
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}
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return false;
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}
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