tests: Add fuzzing harness for ec_seckey_import_der(...) and ec_seckey_export_der(...)

1 files changed, 38 insertions, 0 deletions

diff --git a/src/test/fuzz/secp256k1_ec_seckey_import_export_der.cpp b/src/test/fuzz/secp256k1_ec_seckey_import_export_der.cpp
new file mode 100644
index 0000000000..d4f302a8d3
--- /dev/null
+++ b/src/test/fuzz/secp256k1_ec_seckey_import_export_der.cpp
@@ -0,0 +1,38 @@
+// 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 <key.h>
+#include <secp256k1.h>
+#include <test/fuzz/FuzzedDataProvider.h>
+#include <test/fuzz/fuzz.h>
+#include <test/fuzz/util.h>
+
+#include <cstdint>
+#include <vector>
+
+int ec_seckey_import_der(const secp256k1_context* ctx, unsigned char* out32, const unsigned char* seckey, size_t seckeylen);
+int ec_seckey_export_der(const secp256k1_context* ctx, unsigned char* seckey, size_t* seckeylen, const unsigned char* key32, bool compressed);
+
+void test_one_input(const std::vector<uint8_t>& buffer)
+{
+    FuzzedDataProvider fuzzed_data_provider{buffer.data(), buffer.size()};
+    secp256k1_context* secp256k1_context_sign = secp256k1_context_create(SECP256K1_CONTEXT_SIGN);
+    {
+        std::vector<uint8_t> out32(32);
+        (void)ec_seckey_import_der(secp256k1_context_sign, out32.data(), ConsumeFixedLengthByteVector(fuzzed_data_provider, CKey::SIZE).data(), CKey::SIZE);
+    }
+    {
+        std::vector<uint8_t> seckey(CKey::SIZE);
+        const std::vector<uint8_t> key32 = ConsumeFixedLengthByteVector(fuzzed_data_provider, 32);
+        size_t seckeylen = CKey::SIZE;
+        const bool compressed = fuzzed_data_provider.ConsumeBool();
+        const bool exported = ec_seckey_export_der(secp256k1_context_sign, seckey.data(), &seckeylen, key32.data(), compressed);
+        if (exported) {
+            std::vector<uint8_t> out32(32);
+            const bool imported = ec_seckey_import_der(secp256k1_context_sign, out32.data(), seckey.data(), seckey.size()) == 1;
+            assert(imported && key32 == out32);
+        }
+    }
+    secp256k1_context_destroy(secp256k1_context_sign);
+}