Merge #17229: tests: Add fuzzing harnesses for various Base{32,58,64} and hex related functions

c18405732e38eadb2c47533c3f982f4605fbfd9a tests: Add fuzzing harness for various hex related functions (practicalswift)
526dd78bedcebcf170ce13349eb3e9fc7fbf39bb tests: Add fuzzing harness for various Base{32,58,64} related functions (practicalswift)
32e27129ff26c7cc10321652d5d2678876081983 util: Move TrimString(...). Introduce default pattern (trims whitespace). Add NODISCARD. (practicalswift)
22d9bae36f2a164acf35765231f1d93364c1c4a9 tests: Add corpora suppression (FUZZERS_MISSING_CORPORA) for fuzzers missing in https://github.com/bitcoin-core/qa-assets/tree/master/fuzz_seed_corpus (practicalswift)

Pull request description:

  Add fuzzing harnesses for various Base{32,58,64} and hex related functions.

  **Testing this PR**

  Run:

  ```
  $ CC=clang CXX=clang++ ./configure --enable-fuzz \
        --with-sanitizers=address,fuzzer,undefined
  $ make
  $ src/test/fuzz/base_encode_decode
  …
  $ src/test/fuzz/hex
  …
  ```

ACKs for top commit:
  MarcoFalke:
    ACK c18405732e38eadb2c47533c3f982f4605fbfd9a 🔁

Tree-SHA512: 4fcbe4f641fc553e43fd5c3c40a6beec0d2ce90c5ffc718213b37fc18aba4c055e51e26f93d01ea1248fd89473d07c9dce77db7f014b47d3abd045f61b5f1905

2 files changed, 69 insertions, 0 deletions

diff --git a/src/test/fuzz/base_encode_decode.cpp b/src/test/fuzz/base_encode_decode.cpp
new file mode 100644
index 000000000..cb0fbdf76
--- /dev/null
+++ b/src/test/fuzz/base_encode_decode.cpp
@@ -0,0 +1,47 @@
+// Copyright (c) 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 <test/fuzz/fuzz.h>
+
+#include <base58.h>
+#include <util/string.h>
+#include <util/strencodings.h>
+
+#include <cassert>
+#include <cstdint>
+#include <string>
+#include <vector>
+
+void test_one_input(const std::vector<uint8_t>& buffer)
+{
+    const std::string random_encoded_string(buffer.begin(), buffer.end());
+
+    std::vector<unsigned char> decoded;
+    if (DecodeBase58(random_encoded_string, decoded, 100)) {
+        const std::string encoded_string = EncodeBase58(decoded);
+        assert(encoded_string == TrimString(encoded_string));
+        assert(ToLower(encoded_string) == ToLower(TrimString(random_encoded_string)));
+    }
+
+    if (DecodeBase58Check(random_encoded_string, decoded, 100)) {
+        const std::string encoded_string = EncodeBase58Check(decoded);
+        assert(encoded_string == TrimString(encoded_string));
+        assert(ToLower(encoded_string) == ToLower(TrimString(random_encoded_string)));
+    }
+
+    bool pf_invalid;
+    std::string decoded_string = DecodeBase32(random_encoded_string, &pf_invalid);
+    if (!pf_invalid) {
+        const std::string encoded_string = EncodeBase32(decoded_string);
+        assert(encoded_string == TrimString(encoded_string));
+        assert(ToLower(encoded_string) == ToLower(TrimString(random_encoded_string)));
+    }
+
+    decoded_string = DecodeBase64(random_encoded_string, &pf_invalid);
+    if (!pf_invalid) {
+        const std::string encoded_string = EncodeBase64(decoded_string);
+        assert(encoded_string == TrimString(encoded_string));
+        assert(ToLower(encoded_string) == ToLower(TrimString(random_encoded_string)));
+    }
+}
diff --git a/src/test/fuzz/hex.cpp b/src/test/fuzz/hex.cpp
new file mode 100644
index 000000000..54693180b
--- /dev/null
+++ b/src/test/fuzz/hex.cpp
@@ -0,0 +1,22 @@
+// Copyright (c) 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 <test/fuzz/fuzz.h>
+
+#include <util/strencodings.h>
+
+#include <cassert>
+#include <cstdint>
+#include <string>
+#include <vector>
+
+void test_one_input(const std::vector<uint8_t>& buffer)
+{
+    const std::string random_hex_string(buffer.begin(), buffer.end());
+    const std::vector<unsigned char> data = ParseHex(random_hex_string);
+    const std::string hex_data = HexStr(data);
+    if (IsHex(random_hex_string)) {
+        assert(ToLower(random_hex_string) == hex_data);
+    }
+}