Merge #17357: tests: Add fuzzing harness for Bech32 encoding/decoding

b7541705d0abfbddf682a0134f3fa8a8e1d06cdf tests: Add fuzzing harness for Bech32 encoding/decoding (practicalswift)
85a34b1683233060c4500cfb8e3f5d84c8b8f0da tests: Move CaseInsensitiveEqual to test/util/str (practicalswift)

Pull request description:

  Add fuzzing harness for Bech32 encoding/decoding.

  **Testing this PR**

  Run:

  ```
  $ make distclean
  $ ./autogen.sh
  $ CC=clang CXX=clang++ ./configure --enable-fuzz \
        --with-sanitizers=address,fuzzer,undefined
  $ make
  $ src/test/fuzz/bech32 -max_total_time=60
  …
  ```

ACKs for top commit:
  jonatack:
    ACK b7541705d0abfbddf682a0134f3fa8a8e1d06cdf

Tree-SHA512: ade01d30c6886a083b806dbfff08999cc0d08e687701c670c895e261ed242c789e8a0062d4ebbe8f82676b8f168dc37e83351a88822c9c0eab478572a9e1ec02

5 files changed, 92 insertions, 17 deletions

diff --git a/src/Makefile.test.include b/src/Makefile.test.include
index a4cf78d61b..48afa815d6 100644
--- a/src/Makefile.test.include
+++ b/src/Makefile.test.include
@@ -7,6 +7,7 @@ FUZZ_TARGETS = \
   test/fuzz/address_deserialize \
   test/fuzz/addrman_deserialize \
   test/fuzz/banentry_deserialize \
+  test/fuzz/bech32 \
   test/fuzz/block_deserialize \
   test/fuzz/blockheader_deserialize \
   test/fuzz/blocklocator_deserialize \
@@ -62,14 +63,18 @@ BITCOIN_TEST_SUITE = \
   test/lib/transaction_utils.h \
   test/main.cpp \
   test/setup_common.h \
-  test/setup_common.cpp
+  test/setup_common.cpp \
+  test/util/str.h \
+  test/util/str.cpp
 
 FUZZ_SUITE = \
-  test/setup_common.h \
-  test/setup_common.cpp \
   test/fuzz/fuzz.cpp \
   test/fuzz/fuzz.h \
-  test/fuzz/FuzzedDataProvider.h
+  test/fuzz/FuzzedDataProvider.h \
+  test/setup_common.cpp \
+  test/setup_common.h \
+  test/util/str.cpp \
+  test/util/str.h
 
 FUZZ_SUITE_LD_COMMON = \
  $(LIBBITCOIN_SERVER) \
@@ -242,6 +247,12 @@ test_fuzz_banentry_deserialize_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
 test_fuzz_banentry_deserialize_LDFLAGS = $(RELDFLAGS) $(AM_LDFLAGS) $(LIBTOOL_APP_LDFLAGS)
 test_fuzz_banentry_deserialize_LDADD = $(FUZZ_SUITE_LD_COMMON)
 
+test_fuzz_bech32_SOURCES = $(FUZZ_SUITE) test/fuzz/bech32.cpp
+test_fuzz_bech32_CPPFLAGS = $(AM_CPPFLAGS) $(BITCOIN_INCLUDES)
+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_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)
diff --git a/src/test/bech32_tests.cpp b/src/test/bech32_tests.cpp
index 0ba492c24e..a1dabee579 100644
--- a/src/test/bech32_tests.cpp
+++ b/src/test/bech32_tests.cpp
@@ -4,24 +4,12 @@
 
 #include <bech32.h>
 #include <test/setup_common.h>
+#include <test/util/str.h>
 
 #include <boost/test/unit_test.hpp>
 
 BOOST_FIXTURE_TEST_SUITE(bech32_tests, BasicTestingSetup)
 
-static bool CaseInsensitiveEqual(const std::string &s1, const std::string &s2)
-{
-    if (s1.size() != s2.size()) return false;
-    for (size_t i = 0; i < s1.size(); ++i) {
-        char c1 = s1[i];
-        if (c1 >= 'A' && c1 <= 'Z') c1 -= ('A' - 'a');
-        char c2 = s2[i];
-        if (c2 >= 'A' && c2 <= 'Z') c2 -= ('A' - 'a');
-        if (c1 != c2) return false;
-    }
-    return true;
-}
-
 BOOST_AUTO_TEST_CASE(bip173_testvectors_valid)
 {
     static const std::string CASES[] = {
diff --git a/src/test/fuzz/bech32.cpp b/src/test/fuzz/bech32.cpp
new file mode 100644
index 0000000000..8b91f9bc96
--- /dev/null
+++ b/src/test/fuzz/bech32.cpp
@@ -0,0 +1,43 @@
+// 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 <bech32.h>
+#include <test/fuzz/fuzz.h>
+#include <test/util/str.h>
+#include <util/strencodings.h>
+
+#include <cassert>
+#include <cstdint>
+#include <string>
+#include <utility>
+#include <vector>
+
+void test_one_input(const std::vector<uint8_t>& buffer)
+{
+    const std::string random_string(buffer.begin(), buffer.end());
+    const std::pair<std::string, std::vector<uint8_t>> r1 = bech32::Decode(random_string);
+    if (r1.first.empty()) {
+        assert(r1.second.empty());
+    } else {
+        const std::string& hrp = r1.first;
+        const std::vector<uint8_t>& data = r1.second;
+        const std::string reencoded = bech32::Encode(hrp, data);
+        assert(CaseInsensitiveEqual(random_string, reencoded));
+    }
+
+    std::vector<unsigned char> input;
+    ConvertBits<8, 5, true>([&](unsigned char c) { input.push_back(c); }, buffer.begin(), buffer.end());
+    const std::string encoded = bech32::Encode("bc", input);
+    assert(!encoded.empty());
+
+    const std::pair<std::string, std::vector<uint8_t>> r2 = bech32::Decode(encoded);
+    if (r2.first.empty()) {
+        assert(r2.second.empty());
+    } else {
+        const std::string& hrp = r2.first;
+        const std::vector<uint8_t>& data = r2.second;
+        assert(hrp == "bc");
+        assert(data == input);
+    }
+}
diff --git a/src/test/util/str.cpp b/src/test/util/str.cpp
new file mode 100644
index 0000000000..c517fe44d9
--- /dev/null
+++ b/src/test/util/str.cpp
@@ -0,0 +1,21 @@
+// 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/util/str.h>
+
+#include <cstdint>
+#include <string>
+
+bool CaseInsensitiveEqual(const std::string& s1, const std::string& s2)
+{
+    if (s1.size() != s2.size()) return false;
+    for (size_t i = 0; i < s1.size(); ++i) {
+        char c1 = s1[i];
+        if (c1 >= 'A' && c1 <= 'Z') c1 -= ('A' - 'a');
+        char c2 = s2[i];
+        if (c2 >= 'A' && c2 <= 'Z') c2 -= ('A' - 'a');
+        if (c1 != c2) return false;
+    }
+    return true;
+}
diff --git a/src/test/util/str.h b/src/test/util/str.h
new file mode 100644
index 0000000000..63629501e8
--- /dev/null
+++ b/src/test/util/str.h
@@ -0,0 +1,12 @@
+// 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.
+
+#ifndef BITCOIN_TEST_UTIL_STR_H
+#define BITCOIN_TEST_UTIL_STR_H
+
+#include <string>
+
+bool CaseInsensitiveEqual(const std::string& s1, const std::string& s2);
+
+#endif // BITCOIN_TEST_UTIL_STR_H