Merge #18176: tests: Add fuzzing harness for CScript and CScriptNum operations

e37f53648e3acc6aea75adafec4de2bdbd8cb293 Make lifetime correctness easier to see (avoid reference lifetime extension) (practicalswift)
e7ddbd98937412b2e8b7a3dfacdcacfcbb1d9148 tests: Add fuzzing harness for CScriptNum operations (practicalswift)
65a52a002475056183ea8ee1a42b78aec7d68583 tests: Add fuzzing harness for CScript operations (practicalswift)
eb7c50ca1f4eafed4bb9a20d3012776545a6a433 tests: Add common Consume* fuzzing functions (practicalswift)

Pull request description:

  Add fuzzing harness for `CScript` and `CScriptNum` operations.

  Test this PR using:

  ```
  $ make distclean
  $ ./autogen.sh
  $ CC=clang CXX=clang++ ./configure --enable-fuzz \
        --with-sanitizers=address,fuzzer,undefined
  $ make
  $ src/test/fuzz/script_ops
  …
  $ src/test/fuzz/scriptnum_ops
  …
  ```

ACKs for top commit:
  MarcoFalke:
    ACK e37f53648e3acc6aea75adafec4de2bdbd8cb293 🦂

Tree-SHA512: 5165d918ffe3f1e3e85ab0e61d8b05934f682d324cf63ce188da5890899df2b5727aba9ed10c0437260ecff8055250e60c79d81d764bc740a7652d543a7c5fa3

1 files changed, 67 insertions, 0 deletions

diff --git a/src/test/fuzz/script_ops.cpp b/src/test/fuzz/script_ops.cpp
new file mode 100644
index 000000000..0cd129ba7
--- /dev/null
+++ b/src/test/fuzz/script_ops.cpp
@@ -0,0 +1,67 @@
+// Copyright (c) 2020 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/script.h>
+#include <test/fuzz/FuzzedDataProvider.h>
+#include <test/fuzz/fuzz.h>
+#include <test/fuzz/util.h>
+
+#include <cstdint>
+#include <string>
+#include <vector>
+
+void test_one_input(const std::vector<uint8_t>& buffer)
+{
+    FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
+    CScript script = ConsumeScript(fuzzed_data_provider);
+    while (fuzzed_data_provider.remaining_bytes() > 0) {
+        switch (fuzzed_data_provider.ConsumeIntegralInRange(0, 7)) {
+        case 0:
+            script += ConsumeScript(fuzzed_data_provider);
+            break;
+        case 1:
+            script = script + ConsumeScript(fuzzed_data_provider);
+            break;
+        case 2:
+            script << fuzzed_data_provider.ConsumeIntegral<int64_t>();
+            break;
+        case 3:
+            script << ConsumeOpcodeType(fuzzed_data_provider);
+            break;
+        case 4:
+            script << ConsumeScriptNum(fuzzed_data_provider);
+            break;
+        case 5:
+            script << ConsumeRandomLengthByteVector(fuzzed_data_provider);
+            break;
+        case 6:
+            script.clear();
+            break;
+        case 7: {
+            (void)script.GetSigOpCount(false);
+            (void)script.GetSigOpCount(true);
+            (void)script.GetSigOpCount(script);
+            (void)script.HasValidOps();
+            (void)script.IsPayToScriptHash();
+            (void)script.IsPayToWitnessScriptHash();
+            (void)script.IsPushOnly();
+            (void)script.IsUnspendable();
+            {
+                CScript::const_iterator pc = script.begin();
+                opcodetype opcode;
+                (void)script.GetOp(pc, opcode);
+                std::vector<uint8_t> data;
+                (void)script.GetOp(pc, opcode, data);
+                (void)script.IsPushOnly(pc);
+            }
+            {
+                int version;
+                std::vector<uint8_t> program;
+                (void)script.IsWitnessProgram(version, program);
+            }
+            break;
+        }
+        }
+    }
+}