tests: Add fuzzing harness for various Base{32,58,64} related functions

Author: practicalswift

src/Makefile.test.include

@@ -8,6 +8,7 @@ FUZZ_TARGETS = \
   test/fuzz/address_deserialize \
   test/fuzz/addrman_deserialize \
   test/fuzz/banentry_deserialize \
+  test/fuzz/base_encode_decode \
   test/fuzz/bech32 \
   test/fuzz/block \
   test/fuzz/block_deserialize \
@@ -278,6 +279,12 @@ test_fuzz_bech32_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
 test_fuzz_bech32_LDFLAGS = $(RELDFLAGS) $(AM_LDFLAGS) $(LIBTOOL_APP_LDFLAGS)
 test_fuzz_bech32_LDADD = $(FUZZ_SUITE_LD_COMMON)
 
+test_fuzz_base_encode_decode_SOURCES = $(FUZZ_SUITE) test/fuzz/base_encode_decode.cpp
+test_fuzz_base_encode_decode_CPPFLAGS = $(AM_CPPFLAGS) $(BITCOIN_INCLUDES)
+test_fuzz_base_encode_decode_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
+test_fuzz_base_encode_decode_LDFLAGS = $(RELDFLAGS) $(AM_LDFLAGS) $(LIBTOOL_APP_LDFLAGS)
+test_fuzz_base_encode_decode_LDADD = $(FUZZ_SUITE_LD_COMMON)
+
 test_fuzz_txundo_deserialize_SOURCES = $(FUZZ_SUITE) test/fuzz/deserialize.cpp
 test_fuzz_txundo_deserialize_CPPFLAGS = $(AM_CPPFLAGS) $(BITCOIN_INCLUDES) -DTXUNDO_DESERIALIZE=1
 test_fuzz_txundo_deserialize_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)

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)));
+    }
+}