43 lines
1.1 KiB
C
43 lines
1.1 KiB
C
// Copyright (c) 2016, Google Inc.
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// SPDX-License-Identifier: ISC
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#include <openssl/rand.h>
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#include "internal.h"
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#if defined(OPENSSL_RAND_DETERMINISTIC)
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#include <string.h>
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#include <openssl/chacha.h>
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#include "../internal.h"
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// g_num_calls is the number of calls to |CRYPTO_sysrand| that have occurred.
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//
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// This is intentionally not thread-safe. If the fuzzer mode is ever used in a
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// multi-threaded program, replace this with a thread-local. (A mutex would not
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// be deterministic.)
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static uint64_t g_num_calls = 0;
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static struct CRYPTO_STATIC_MUTEX g_num_calls_lock = CRYPTO_STATIC_MUTEX_INIT;
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void RAND_reset_for_fuzzing(void) { g_num_calls = 0; }
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void CRYPTO_sysrand(uint8_t *out, size_t requested) {
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static const uint8_t kZeroKey[32];
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CRYPTO_STATIC_MUTEX_lock_write(&g_num_calls_lock);
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uint64_t num_calls = g_num_calls++;
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CRYPTO_STATIC_MUTEX_unlock_write(&g_num_calls_lock);
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uint8_t nonce[12];
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OPENSSL_memset(nonce, 0, sizeof(nonce));
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OPENSSL_memcpy(nonce, &num_calls, sizeof(num_calls));
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OPENSSL_memset(out, 0, requested);
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CRYPTO_chacha_20(out, out, requested, kZeroKey, nonce, 0);
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}
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#endif // OPENSSL_RAND_DETERMINISTIC
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