tests: Add fuzzing harness for ChaCha20Poly1305AEAD

Author: practicalswift

src/Makefile.test.include

@@ -36,6 +36,7 @@ FUZZ_TARGETS = \
   test/fuzz/crypto_aes256 \
   test/fuzz/crypto_aes256cbc \
   test/fuzz/crypto_chacha20 \
+  test/fuzz/crypto_chacha20_poly1305_aead \
   test/fuzz/crypto_common \
   test/fuzz/crypto_hkdf_hmac_sha256_l32 \
   test/fuzz/crypto_poly1305 \
@@ -509,6 +510,12 @@ test_fuzz_crypto_chacha20_LDADD = $(FUZZ_SUITE_LD_COMMON)
 test_fuzz_crypto_chacha20_LDFLAGS = $(RELDFLAGS) $(AM_LDFLAGS) $(LIBTOOL_APP_LDFLAGS)
 test_fuzz_crypto_chacha20_SOURCES = test/fuzz/crypto_chacha20.cpp
 
+test_fuzz_crypto_chacha20_poly1305_aead_CPPFLAGS = $(AM_CPPFLAGS) $(BITCOIN_INCLUDES)
+test_fuzz_crypto_chacha20_poly1305_aead_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
+test_fuzz_crypto_chacha20_poly1305_aead_LDADD = $(FUZZ_SUITE_LD_COMMON)
+test_fuzz_crypto_chacha20_poly1305_aead_LDFLAGS = $(RELDFLAGS) $(AM_LDFLAGS) $(LIBTOOL_APP_LDFLAGS)
+test_fuzz_crypto_chacha20_poly1305_aead_SOURCES = test/fuzz/crypto_chacha20_poly1305_aead.cpp
+
 test_fuzz_crypto_common_CPPFLAGS = $(AM_CPPFLAGS) $(BITCOIN_INCLUDES)
 test_fuzz_crypto_common_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
 test_fuzz_crypto_common_LDADD = $(FUZZ_SUITE_LD_COMMON)

src/test/fuzz/crypto_chacha20_poly1305_aead.cpp

@@ -0,0 +1,72 @@
+// 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 <crypto/chacha_poly_aead.h>
+#include <crypto/poly1305.h>
+#include <test/fuzz/FuzzedDataProvider.h>
+#include <test/fuzz/fuzz.h>
+#include <test/fuzz/util.h>
+
+#include <cassert>
+#include <cstdint>
+#include <limits>
+#include <vector>
+
+void test_one_input(const std::vector<uint8_t>& buffer)
+{
+    FuzzedDataProvider fuzzed_data_provider{buffer.data(), buffer.size()};
+
+    const std::vector<uint8_t> k1 = ConsumeFixedLengthByteVector(fuzzed_data_provider, CHACHA20_POLY1305_AEAD_KEY_LEN);
+    const std::vector<uint8_t> k2 = ConsumeFixedLengthByteVector(fuzzed_data_provider, CHACHA20_POLY1305_AEAD_KEY_LEN);
+
+    ChaCha20Poly1305AEAD aead(k1.data(), k1.size(), k2.data(), k2.size());
+    uint64_t seqnr_payload = 0;
+    uint64_t seqnr_aad = 0;
+    int aad_pos = 0;
+    size_t buffer_size = fuzzed_data_provider.ConsumeIntegralInRange<size_t>(0, 4096);
+    std::vector<uint8_t> in(buffer_size + CHACHA20_POLY1305_AEAD_AAD_LEN + POLY1305_TAGLEN, 0);
+    std::vector<uint8_t> out(buffer_size + CHACHA20_POLY1305_AEAD_AAD_LEN + POLY1305_TAGLEN, 0);
+    bool is_encrypt = fuzzed_data_provider.ConsumeBool();
+    while (fuzzed_data_provider.ConsumeBool()) {
+        switch (fuzzed_data_provider.ConsumeIntegralInRange<int>(0, 6)) {
+        case 0: {
+            buffer_size = fuzzed_data_provider.ConsumeIntegralInRange<size_t>(64, 4096);
+            in = std::vector<uint8_t>(buffer_size + CHACHA20_POLY1305_AEAD_AAD_LEN + POLY1305_TAGLEN, 0);
+            out = std::vector<uint8_t>(buffer_size + CHACHA20_POLY1305_AEAD_AAD_LEN + POLY1305_TAGLEN, 0);
+            break;
+        }
+        case 1: {
+            (void)aead.Crypt(seqnr_payload, seqnr_aad, aad_pos, out.data(), out.size(), in.data(), buffer_size, is_encrypt);
+            break;
+        }
+        case 2: {
+            uint32_t len = 0;
+            const bool ok = aead.GetLength(&len, seqnr_aad, aad_pos, in.data());
+            assert(ok);
+            break;
+        }
+        case 3: {
+            seqnr_payload += 1;
+            aad_pos += CHACHA20_POLY1305_AEAD_AAD_LEN;
+            if (aad_pos + CHACHA20_POLY1305_AEAD_AAD_LEN > CHACHA20_ROUND_OUTPUT) {
+                aad_pos = 0;
+                seqnr_aad += 1;
+            }
+            break;
+        }
+        case 4: {
+            seqnr_payload = fuzzed_data_provider.ConsumeIntegral<int>();
+            break;
+        }
+        case 5: {
+            seqnr_aad = fuzzed_data_provider.ConsumeIntegral<int>();
+            break;
+        }
+        case 6: {
+            is_encrypt = fuzzed_data_provider.ConsumeBool();
+            break;
+        }
+        }
+    }
+}