bc5b2a2e22
If running the stack through a fuzzer, we would like execution to be completely deterministic. This is gated on a BORINGSSL_UNSAFE_FUZZER_MODE #ifdef. For now, this just uses the zero ChaCha20 key and a global counter. As needed, we can extend this to a thread-local counter and a separate ChaCha20 stream and counter per input length. Change-Id: Ic6c9d8a25e70d68e5dc6804e2c234faf48e51395 Reviewed-on: https://boringssl-review.googlesource.com/7286 Reviewed-by: Adam Langley <agl@google.com>
50 lines
1.6 KiB
C
50 lines
1.6 KiB
C
/* Copyright (c) 2016, Google Inc.
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
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* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
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* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
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#include <openssl/rand.h>
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#if defined(BORINGSSL_UNSAFE_FUZZER_MODE)
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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 occured.
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*
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* TODO(davidben): This is intentionally not thread-safe. If the fuzzer mode is
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* ever used in a multi-threaded program, replace this with a thread-local. (A
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* mutex would not be deterministic.) */
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static uint64_t g_num_calls = 0;
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void RAND_cleanup(void) {}
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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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uint8_t nonce[12];
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memset(nonce, 0, sizeof(nonce));
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memcpy(nonce, &g_num_calls, sizeof(g_num_calls));
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memset(out, 0, requested);
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CRYPTO_chacha_20(out, out, requested, kZeroKey, nonce, 0);
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g_num_calls++;
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}
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#endif /* BORINGSSL_UNSAFE_FUZZER_MODE */
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