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-rw-r--r--src/test/fuzz/FuzzedDataProvider.h245
-rw-r--r--src/test/fuzz/eval_script.cpp30
2 files changed, 275 insertions, 0 deletions
diff --git a/src/test/fuzz/FuzzedDataProvider.h b/src/test/fuzz/FuzzedDataProvider.h
new file mode 100644
index 0000000000..1b5b4bb012
--- /dev/null
+++ b/src/test/fuzz/FuzzedDataProvider.h
@@ -0,0 +1,245 @@
+//===- FuzzedDataProvider.h - Utility header for fuzz targets ---*- C++ -* ===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+// A single header library providing an utility class to break up an array of
+// bytes. Whenever run on the same input, provides the same output, as long as
+// its methods are called in the same order, with the same arguments.
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_FUZZER_FUZZED_DATA_PROVIDER_H_
+#define LLVM_FUZZER_FUZZED_DATA_PROVIDER_H_
+
+#include <limits.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#include <algorithm>
+#include <cstring>
+#include <initializer_list>
+#include <string>
+#include <type_traits>
+#include <utility>
+#include <vector>
+
+class FuzzedDataProvider {
+public:
+ // |data| is an array of length |size| that the FuzzedDataProvider wraps to
+ // provide more granular access. |data| must outlive the FuzzedDataProvider.
+ FuzzedDataProvider(const uint8_t *data, size_t size)
+ : data_ptr_(data), remaining_bytes_(size) {}
+ ~FuzzedDataProvider() = default;
+
+ // Returns a std::vector containing |num_bytes| of input data. If fewer than
+ // |num_bytes| of data remain, returns a shorter std::vector containing all
+ // of the data that's left. Can be used with any byte sized type, such as
+ // char, unsigned char, uint8_t, etc.
+ template <typename T> std::vector<T> ConsumeBytes(size_t num_bytes) {
+ num_bytes = std::min(num_bytes, remaining_bytes_);
+ return ConsumeBytes<T>(num_bytes, num_bytes);
+ }
+
+ // Similar to |ConsumeBytes|, but also appends the terminator value at the end
+ // of the resulting vector. Useful, when a mutable null-terminated C-string is
+ // needed, for example. But that is a rare case. Better avoid it, if possible,
+ // and prefer using |ConsumeBytes| or |ConsumeBytesAsString| methods.
+ template <typename T>
+ std::vector<T> ConsumeBytesWithTerminator(size_t num_bytes,
+ T terminator = 0) {
+ num_bytes = std::min(num_bytes, remaining_bytes_);
+ std::vector<T> result = ConsumeBytes<T>(num_bytes + 1, num_bytes);
+ result.back() = terminator;
+ return result;
+ }
+
+ // Returns a std::string containing |num_bytes| of input data. Using this and
+ // |.c_str()| on the resulting string is the best way to get an immutable
+ // null-terminated C string. If fewer than |num_bytes| of data remain, returns
+ // a shorter std::string containing all of the data that's left.
+ std::string ConsumeBytesAsString(size_t num_bytes) {
+ static_assert(sizeof(std::string::value_type) == sizeof(uint8_t),
+ "ConsumeBytesAsString cannot convert the data to a string.");
+
+ num_bytes = std::min(num_bytes, remaining_bytes_);
+ std::string result(
+ reinterpret_cast<const std::string::value_type *>(data_ptr_),
+ num_bytes);
+ Advance(num_bytes);
+ return result;
+ }
+
+ // Returns a number in the range [min, max] by consuming bytes from the
+ // input data. The value might not be uniformly distributed in the given
+ // range. If there's no input data left, always returns |min|. |min| must
+ // be less than or equal to |max|.
+ template <typename T> T ConsumeIntegralInRange(T min, T max) {
+ static_assert(std::is_integral<T>::value, "An integral type is required.");
+ static_assert(sizeof(T) <= sizeof(uint64_t), "Unsupported integral type.");
+
+ if (min > max)
+ abort();
+
+ // Use the biggest type possible to hold the range and the result.
+ uint64_t range = static_cast<uint64_t>(max) - min;
+ uint64_t result = 0;
+ size_t offset = 0;
+
+ while (offset < sizeof(T) * CHAR_BIT && (range >> offset) > 0 &&
+ remaining_bytes_ != 0) {
+ // Pull bytes off the end of the seed data. Experimentally, this seems to
+ // allow the fuzzer to more easily explore the input space. This makes
+ // sense, since it works by modifying inputs that caused new code to run,
+ // and this data is often used to encode length of data read by
+ // |ConsumeBytes|. Separating out read lengths makes it easier modify the
+ // contents of the data that is actually read.
+ --remaining_bytes_;
+ result = (result << CHAR_BIT) | data_ptr_[remaining_bytes_];
+ offset += CHAR_BIT;
+ }
+
+ // Avoid division by 0, in case |range + 1| results in overflow.
+ if (range != std::numeric_limits<decltype(range)>::max())
+ result = result % (range + 1);
+
+ return static_cast<T>(min + result);
+ }
+
+ // Returns a std::string of length from 0 to |max_length|. When it runs out of
+ // input data, returns what remains of the input. Designed to be more stable
+ // with respect to a fuzzer inserting characters than just picking a random
+ // length and then consuming that many bytes with |ConsumeBytes|.
+ std::string ConsumeRandomLengthString(size_t max_length) {
+ // Reads bytes from the start of |data_ptr_|. Maps "\\" to "\", and maps "\"
+ // followed by anything else to the end of the string. As a result of this
+ // logic, a fuzzer can insert characters into the string, and the string
+ // will be lengthened to include those new characters, resulting in a more
+ // stable fuzzer than picking the length of a string independently from
+ // picking its contents.
+ std::string result;
+
+ // Reserve the anticipated capaticity to prevent several reallocations.
+ result.reserve(std::min(max_length, remaining_bytes_));
+ for (size_t i = 0; i < max_length && remaining_bytes_ != 0; ++i) {
+ char next = ConvertUnsignedToSigned<char>(data_ptr_[0]);
+ Advance(1);
+ if (next == '\\' && remaining_bytes_ != 0) {
+ next = ConvertUnsignedToSigned<char>(data_ptr_[0]);
+ Advance(1);
+ if (next != '\\')
+ break;
+ }
+ result += next;
+ }
+
+ result.shrink_to_fit();
+ return result;
+ }
+
+ // Returns a std::vector containing all remaining bytes of the input data.
+ template <typename T> std::vector<T> ConsumeRemainingBytes() {
+ return ConsumeBytes<T>(remaining_bytes_);
+ }
+
+ // Prefer using |ConsumeRemainingBytes| unless you actually need a std::string
+ // object.
+ // Returns a std::vector containing all remaining bytes of the input data.
+ std::string ConsumeRemainingBytesAsString() {
+ return ConsumeBytesAsString(remaining_bytes_);
+ }
+
+ // Returns a number in the range [Type's min, Type's max]. The value might
+ // not be uniformly distributed in the given range. If there's no input data
+ // left, always returns |min|.
+ template <typename T> T ConsumeIntegral() {
+ return ConsumeIntegralInRange(std::numeric_limits<T>::min(),
+ std::numeric_limits<T>::max());
+ }
+
+ // Reads one byte and returns a bool, or false when no data remains.
+ bool ConsumeBool() { return 1 & ConsumeIntegral<uint8_t>(); }
+
+ // Returns a copy of a value selected from a fixed-size |array|.
+ template <typename T, size_t size>
+ T PickValueInArray(const T (&array)[size]) {
+ static_assert(size > 0, "The array must be non empty.");
+ return array[ConsumeIntegralInRange<size_t>(0, size - 1)];
+ }
+
+ template <typename T>
+ T PickValueInArray(std::initializer_list<const T> list) {
+ // static_assert(list.size() > 0, "The array must be non empty.");
+ return *(list.begin() + ConsumeIntegralInRange<size_t>(0, list.size() - 1));
+ }
+
+ // Return an enum value. The enum must start at 0 and be contiguous. It must
+ // also contain |kMaxValue| aliased to its largest (inclusive) value. Such as:
+ // enum class Foo { SomeValue, OtherValue, kMaxValue = OtherValue };
+ template <typename T> T ConsumeEnum() {
+ static_assert(std::is_enum<T>::value, "|T| must be an enum type.");
+ return static_cast<T>(ConsumeIntegralInRange<uint32_t>(
+ 0, static_cast<uint32_t>(T::kMaxValue)));
+ }
+
+ // Reports the remaining bytes available for fuzzed input.
+ size_t remaining_bytes() { return remaining_bytes_; }
+
+private:
+ FuzzedDataProvider(const FuzzedDataProvider &) = delete;
+ FuzzedDataProvider &operator=(const FuzzedDataProvider &) = delete;
+
+ void Advance(size_t num_bytes) {
+ if (num_bytes > remaining_bytes_)
+ abort();
+
+ data_ptr_ += num_bytes;
+ remaining_bytes_ -= num_bytes;
+ }
+
+ template <typename T>
+ std::vector<T> ConsumeBytes(size_t size, size_t num_bytes_to_consume) {
+ static_assert(sizeof(T) == sizeof(uint8_t), "Incompatible data type.");
+
+ // The point of using the size-based constructor below is to increase the
+ // odds of having a vector object with capacity being equal to the length.
+ // That part is always implementation specific, but at least both libc++ and
+ // libstdc++ allocate the requested number of bytes in that constructor,
+ // which seems to be a natural choice for other implementations as well.
+ // To increase the odds even more, we also call |shrink_to_fit| below.
+ std::vector<T> result(size);
+ std::memcpy(result.data(), data_ptr_, num_bytes_to_consume);
+ Advance(num_bytes_to_consume);
+
+ // Even though |shrink_to_fit| is also implementation specific, we expect it
+ // to provide an additional assurance in case vector's constructor allocated
+ // a buffer which is larger than the actual amount of data we put inside it.
+ result.shrink_to_fit();
+ return result;
+ }
+
+ template <typename TS, typename TU> TS ConvertUnsignedToSigned(TU value) {
+ static_assert(sizeof(TS) == sizeof(TU), "Incompatible data types.");
+ static_assert(!std::numeric_limits<TU>::is_signed,
+ "Source type must be unsigned.");
+
+ // TODO(Dor1s): change to `if constexpr` once C++17 becomes mainstream.
+ if (std::numeric_limits<TS>::is_modulo)
+ return static_cast<TS>(value);
+
+ // Avoid using implementation-defined unsigned to signer conversions.
+ // To learn more, see https://stackoverflow.com/questions/13150449.
+ if (value <= std::numeric_limits<TS>::max())
+ return static_cast<TS>(value);
+ else {
+ constexpr auto TS_min = std::numeric_limits<TS>::min();
+ return TS_min + static_cast<char>(value - TS_min);
+ }
+ }
+
+ const uint8_t *data_ptr_;
+ size_t remaining_bytes_;
+};
+
+#endif // LLVM_FUZZER_FUZZED_DATA_PROVIDER_H_
diff --git a/src/test/fuzz/eval_script.cpp b/src/test/fuzz/eval_script.cpp
new file mode 100644
index 0000000000..9444cd489e
--- /dev/null
+++ b/src/test/fuzz/eval_script.cpp
@@ -0,0 +1,30 @@
+// Copyright (c) 2009-2019 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <script/interpreter.h>
+#include <test/fuzz/FuzzedDataProvider.h>
+#include <test/fuzz/fuzz.h>
+
+#include <limits>
+
+void test_one_input(const std::vector<uint8_t>& buffer)
+{
+ FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
+ const unsigned int flags = fuzzed_data_provider.ConsumeIntegral<unsigned int>();
+ const std::vector<uint8_t> script_bytes = [&] {
+ if (fuzzed_data_provider.remaining_bytes() != 0) {
+ return fuzzed_data_provider.ConsumeRemainingBytes<uint8_t>();
+ } else {
+ // Avoid UBSan warning:
+ // test/fuzz/FuzzedDataProvider.h:212:17: runtime error: null pointer passed as argument 1, which is declared to never be null
+ // /usr/include/string.h:43:28: note: nonnull attribute specified here
+ return std::vector<uint8_t>();
+ }
+ }();
+ const CScript script(script_bytes.begin(), script_bytes.end());
+ for (const auto sig_version : {SigVersion::BASE, SigVersion::WITNESS_V0}) {
+ std::vector<std::vector<unsigned char>> stack;
+ (void)EvalScript(stack, script, flags, BaseSignatureChecker(), sig_version, nullptr);
+ }
+}
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