Merge bitcoin/bitcoin#21169: fuzz: Add RPC interface fuzzing. Increase fuzzing coverage from 65% to 70%.

545404e fuzz: Add RPC interface fuzzing. Increase fuzzing coverage from 65% to 70%. (practicalswift)

Pull request description:

  Add RPC interface fuzzing.

  This PR increases overall fuzzing line coverage from [~65%](https://marcofalke.github.io/btc_cov/fuzz.coverage/) to ~70% 🎉

  To test this PR:

  ```
  $ make distclean
  $ ./autogen.sh
  $ CC=clang CXX=clang++ ./configure --enable-fuzz --with-sanitizers=address,fuzzer,undefined
  $ make -C src/ test/fuzz/fuzz
  $ FUZZ=rpc src/test/fuzz/fuzz
  ```

  See [`doc/fuzzing.md`](https://github.com/bitcoin/bitcoin/blob/master/doc/fuzzing.md) for more information on how to fuzz Bitcoin Core. Don't forget to contribute any coverage increasing inputs you find to the [Bitcoin Core fuzzing corpus repo](https://github.com/bitcoin-core/qa-assets).

  Happy fuzzing :)

ACKs for top commit:
  MarcoFalke:
    Concept ACK 545404e

Tree-SHA512: 35fc1b508af42bf480ee3762326b09ff2eecdb7960a1917ad16345fadd5c0c21d666dafe736176e5a848ff6492483c782e4ea914cd9000faf50190df051950fd

Author: MarcoFalke

src/Makefile.test.include

@@ -274,6 +274,7 @@ test_fuzz_fuzz_SOURCES = \
  test/fuzz/random.cpp \
  test/fuzz/rbf.cpp \
  test/fuzz/rolling_bloom_filter.cpp \
+ test/fuzz/rpc.cpp \
  test/fuzz/script.cpp \
  test/fuzz/script_assets_test_minimizer.cpp \
  test/fuzz/script_bitcoin_consensus.cpp \

src/test/fuzz/rpc.cpp

@@ -0,0 +1,378 @@
+// Copyright (c) 2021 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 <base58.h>
+#include <chainparamsbase.h>
+#include <core_io.h>
+#include <interfaces/chain.h>
+#include <key.h>
+#include <key_io.h>
+#include <node/context.h>
+#include <primitives/block.h>
+#include <primitives/transaction.h>
+#include <psbt.h>
+#include <rpc/blockchain.h>
+#include <rpc/client.h>
+#include <rpc/request.h>
+#include <rpc/server.h>
+#include <rpc/util.h>
+#include <span.h>
+#include <streams.h>
+#include <test/fuzz/FuzzedDataProvider.h>
+#include <test/fuzz/fuzz.h>
+#include <test/fuzz/util.h>
+#include <test/util/setup_common.h>
+#include <tinyformat.h>
+#include <univalue.h>
+#include <util/strencodings.h>
+#include <util/string.h>
+#include <util/time.h>
+
+#include <cstdint>
+#include <iostream>
+#include <memory>
+#include <optional>
+#include <stdexcept>
+#include <string>
+#include <vector>
+
+namespace {
+struct RPCFuzzTestingSetup : public TestingSetup {
+    RPCFuzzTestingSetup(const std::string& chain_name, const std::vector<const char*>& extra_args) : TestingSetup{chain_name, extra_args}
+    {
+    }
+
+    UniValue CallRPC(const std::string& rpc_method, const std::vector<std::string>& arguments)
+    {
+        JSONRPCRequest request;
+        request.context = &m_node;
+        request.strMethod = rpc_method;
+        request.params = RPCConvertValues(rpc_method, arguments);
+        return tableRPC.execute(request);
+    }
+
+    std::vector<std::string> GetRPCCommands() const
+    {
+        return tableRPC.listCommands();
+    }
+};
+
+RPCFuzzTestingSetup* rpc_testing_setup = nullptr;
+std::string g_limit_to_rpc_command;
+
+// RPC commands which are not appropriate for fuzzing: such as RPC commands
+// reading or writing to a filename passed as an RPC parameter, RPC commands
+// resulting in network activity, etc.
+const std::vector<std::string> RPC_COMMANDS_NOT_SAFE_FOR_FUZZING{
+    "addconnection",  // avoid DNS lookups
+    "addnode",        // avoid DNS lookups
+    "addpeeraddress", // avoid DNS lookups
+    "analyzepsbt",    // avoid signed integer overflow in CFeeRate::GetFee(unsigned long) (https://github.com/bitcoin/bitcoin/issues/20607)
+    "dumptxoutset",   // avoid writing to disk
+#ifdef ENABLE_WALLET
+    "dumpwallet", // avoid writing to disk
+#endif
+    "echoipc",           // avoid assertion failure (Assertion `"EnsureAnyNodeContext(request.context).init" && check' failed.)
+    "generatetoaddress", // avoid timeout
+    "gettxoutproof",     // avoid slow execution
+#ifdef ENABLE_WALLET
+    "importwallet", // avoid reading from disk
+    "loadwallet",   // avoid reading from disk
+#endif
+    "mockscheduler",         // avoid assertion failure (Assertion `delta_seconds.count() > 0 && delta_seconds < std::chrono::hours{1}' failed.)
+    "prioritisetransaction", // avoid signed integer overflow in CTxMemPool::PrioritiseTransaction(uint256 const&, long const&) (https://github.com/bitcoin/bitcoin/issues/20626)
+    "setban",                // avoid DNS lookups
+    "stop",                  // avoid shutdown state
+};
+
+// RPC commands which are safe for fuzzing.
+const std::vector<std::string> RPC_COMMANDS_SAFE_FOR_FUZZING{
+    "clearbanned",
+    "combinepsbt",
+    "combinerawtransaction",
+    "converttopsbt",
+    "createmultisig",
+    "createpsbt",
+    "createrawtransaction",
+    "decodepsbt",
+    "decoderawtransaction",
+    "decodescript",
+    "deriveaddresses",
+    "disconnectnode",
+    "echo",
+    "echojson",
+    "estimaterawfee",
+    "estimatesmartfee",
+    "finalizepsbt",
+    "generate",
+    "generateblock",
+    "generatetodescriptor",
+    "getaddednodeinfo",
+    "getbestblockhash",
+    "getblock",
+    "getblockchaininfo",
+    "getblockcount",
+    "getblockfilter",
+    "getblockhash",
+    "getblockheader",
+    "getblockstats",
+    "getblocktemplate",
+    "getchaintips",
+    "getchaintxstats",
+    "getconnectioncount",
+    "getdescriptorinfo",
+    "getdifficulty",
+    "getindexinfo",
+    "getmemoryinfo",
+    "getmempoolancestors",
+    "getmempooldescendants",
+    "getmempoolentry",
+    "getmempoolinfo",
+    "getmininginfo",
+    "getnettotals",
+    "getnetworkhashps",
+    "getnetworkinfo",
+    "getnodeaddresses",
+    "getpeerinfo",
+    "getrawmempool",
+    "getrawtransaction",
+    "getrpcinfo",
+    "gettxout",
+    "gettxoutsetinfo",
+    "help",
+    "invalidateblock",
+    "joinpsbts",
+    "listbanned",
+    "logging",
+    "ping",
+    "preciousblock",
+    "pruneblockchain",
+    "reconsiderblock",
+    "savemempool",
+    "scantxoutset",
+    "sendrawtransaction",
+    "setmocktime",
+    "setnetworkactive",
+    "signmessagewithprivkey",
+    "signrawtransactionwithkey",
+    "submitblock",
+    "submitheader",
+    "syncwithvalidationinterfacequeue",
+    "testmempoolaccept",
+    "uptime",
+    "utxoupdatepsbt",
+    "validateaddress",
+    "verifychain",
+    "verifymessage",
+    "verifytxoutproof",
+    "waitforblock",
+    "waitforblockheight",
+    "waitfornewblock",
+};
+
+std::string ConsumeScalarRPCArgument(FuzzedDataProvider& fuzzed_data_provider)
+{
+    const size_t max_string_length = 4096;
+    std::string r;
+    CallOneOf(
+        fuzzed_data_provider,
+        [&] {
+            // string argument
+            r = fuzzed_data_provider.ConsumeRandomLengthString(max_string_length);
+        },
+        [&] {
+            // base64 argument
+            r = EncodeBase64(fuzzed_data_provider.ConsumeRandomLengthString(max_string_length));
+        },
+        [&] {
+            // hex argument
+            r = HexStr(fuzzed_data_provider.ConsumeRandomLengthString(max_string_length));
+        },
+        [&] {
+            // bool argument
+            r = fuzzed_data_provider.ConsumeBool() ? "true" : "false";
+        },
+        [&] {
+            // range argument
+            r = "[" + ToString(fuzzed_data_provider.ConsumeIntegral<int64_t>()) + "," + ToString(fuzzed_data_provider.ConsumeIntegral<int64_t>()) + "]";
+        },
+        [&] {
+            // integral argument (int64_t)
+            r = ToString(fuzzed_data_provider.ConsumeIntegral<int64_t>());
+        },
+        [&] {
+            // integral argument (uint64_t)
+            r = ToString(fuzzed_data_provider.ConsumeIntegral<uint64_t>());
+        },
+        [&] {
+            // floating point argument
+            r = strprintf("%f", fuzzed_data_provider.ConsumeFloatingPoint<double>());
+        },
+        [&] {
+            // tx destination argument
+            r = EncodeDestination(ConsumeTxDestination(fuzzed_data_provider));
+        },
+        [&] {
+            // uint160 argument
+            r = ConsumeUInt160(fuzzed_data_provider).ToString();
+        },
+        [&] {
+            // uint256 argument
+            r = ConsumeUInt256(fuzzed_data_provider).ToString();
+        },
+        [&] {
+            // base32 argument
+            r = EncodeBase32(fuzzed_data_provider.ConsumeRandomLengthString(max_string_length));
+        },
+        [&] {
+            // base58 argument
+            r = EncodeBase58(MakeUCharSpan(fuzzed_data_provider.ConsumeRandomLengthString(max_string_length)));
+        },
+        [&] {
+            // base58 argument with checksum
+            r = EncodeBase58Check(MakeUCharSpan(fuzzed_data_provider.ConsumeRandomLengthString(max_string_length)));
+        },
+        [&] {
+            // hex encoded block
+            std::optional<CBlock> opt_block = ConsumeDeserializable<CBlock>(fuzzed_data_provider);
+            if (!opt_block) {
+                return;
+            }
+            CDataStream data_stream{SER_NETWORK, PROTOCOL_VERSION};
+            data_stream << *opt_block;
+            r = HexStr(data_stream);
+        },
+        [&] {
+            // hex encoded block header
+            std::optional<CBlockHeader> opt_block_header = ConsumeDeserializable<CBlockHeader>(fuzzed_data_provider);
+            if (!opt_block_header) {
+                return;
+            }
+            CDataStream data_stream{SER_NETWORK, PROTOCOL_VERSION};
+            data_stream << *opt_block_header;
+            r = HexStr(data_stream);
+        },
+        [&] {
+            // hex encoded tx
+            std::optional<CMutableTransaction> opt_tx = ConsumeDeserializable<CMutableTransaction>(fuzzed_data_provider);
+            if (!opt_tx) {
+                return;
+            }
+            CDataStream data_stream{SER_NETWORK, fuzzed_data_provider.ConsumeBool() ? PROTOCOL_VERSION : (PROTOCOL_VERSION | SERIALIZE_TRANSACTION_NO_WITNESS)};
+            data_stream << *opt_tx;
+            r = HexStr(data_stream);
+        },
+        [&] {
+            // base64 encoded psbt
+            std::optional<PartiallySignedTransaction> opt_psbt = ConsumeDeserializable<PartiallySignedTransaction>(fuzzed_data_provider);
+            if (!opt_psbt) {
+                return;
+            }
+            CDataStream data_stream{SER_NETWORK, PROTOCOL_VERSION};
+            data_stream << *opt_psbt;
+            r = EncodeBase64({data_stream.begin(), data_stream.end()});
+        },
+        [&] {
+            // base58 encoded key
+            const std::vector<uint8_t> random_bytes = fuzzed_data_provider.ConsumeBytes<uint8_t>(32);
+            CKey key;
+            key.Set(random_bytes.begin(), random_bytes.end(), fuzzed_data_provider.ConsumeBool());
+            if (!key.IsValid()) {
+                return;
+            }
+            r = EncodeSecret(key);
+        },
+        [&] {
+            // hex encoded pubkey
+            const std::vector<uint8_t> random_bytes = fuzzed_data_provider.ConsumeBytes<uint8_t>(32);
+            CKey key;
+            key.Set(random_bytes.begin(), random_bytes.end(), fuzzed_data_provider.ConsumeBool());
+            if (!key.IsValid()) {
+                return;
+            }
+            r = HexStr(key.GetPubKey());
+        });
+    return r;
+}
+
+std::string ConsumeArrayRPCArgument(FuzzedDataProvider& fuzzed_data_provider)
+{
+    std::vector<std::string> scalar_arguments;
+    while (fuzzed_data_provider.ConsumeBool()) {
+        scalar_arguments.push_back(ConsumeScalarRPCArgument(fuzzed_data_provider));
+    }
+    return "[\"" + Join(scalar_arguments, "\",\"") + "\"]";
+}
+
+std::string ConsumeRPCArgument(FuzzedDataProvider& fuzzed_data_provider)
+{
+    return fuzzed_data_provider.ConsumeBool() ? ConsumeScalarRPCArgument(fuzzed_data_provider) : ConsumeArrayRPCArgument(fuzzed_data_provider);
+}
+
+RPCFuzzTestingSetup* InitializeRPCFuzzTestingSetup()
+{
+    static const auto setup = MakeNoLogFileContext<RPCFuzzTestingSetup>();
+    SetRPCWarmupFinished();
+    return setup.get();
+}
+}; // namespace
+
+void initialize_rpc()
+{
+    rpc_testing_setup = InitializeRPCFuzzTestingSetup();
+    const std::vector<std::string> supported_rpc_commands = rpc_testing_setup->GetRPCCommands();
+    for (const std::string& rpc_command : supported_rpc_commands) {
+        const bool safe_for_fuzzing = std::find(RPC_COMMANDS_SAFE_FOR_FUZZING.begin(), RPC_COMMANDS_SAFE_FOR_FUZZING.end(), rpc_command) != RPC_COMMANDS_SAFE_FOR_FUZZING.end();
+        const bool not_safe_for_fuzzing = std::find(RPC_COMMANDS_NOT_SAFE_FOR_FUZZING.begin(), RPC_COMMANDS_NOT_SAFE_FOR_FUZZING.end(), rpc_command) != RPC_COMMANDS_NOT_SAFE_FOR_FUZZING.end();
+        if (!(safe_for_fuzzing || not_safe_for_fuzzing)) {
+            std::cerr << "Error: RPC command \"" << rpc_command << "\" not found in RPC_COMMANDS_SAFE_FOR_FUZZING or RPC_COMMANDS_NOT_SAFE_FOR_FUZZING. Please update " << __FILE__ << ".\n";
+            std::terminate();
+        }
+        if (safe_for_fuzzing && not_safe_for_fuzzing) {
+            std::cerr << "Error: RPC command \"" << rpc_command << "\" found in *both* RPC_COMMANDS_SAFE_FOR_FUZZING and RPC_COMMANDS_NOT_SAFE_FOR_FUZZING. Please update " << __FILE__ << ".\n";
+            std::terminate();
+        }
+    }
+    for (const std::string& rpc_command : RPC_COMMANDS_SAFE_FOR_FUZZING) {
+        const bool supported_rpc_command = std::find(supported_rpc_commands.begin(), supported_rpc_commands.end(), rpc_command) != supported_rpc_commands.end();
+        if (!supported_rpc_command) {
+            std::cerr << "Error: Unknown RPC command \"" << rpc_command << "\" found in RPC_COMMANDS_SAFE_FOR_FUZZING. Please update " << __FILE__ << ".\n";
+            std::terminate();
+        }
+    }
+    for (const std::string& rpc_command : RPC_COMMANDS_NOT_SAFE_FOR_FUZZING) {
+        const bool supported_rpc_command = std::find(supported_rpc_commands.begin(), supported_rpc_commands.end(), rpc_command) != supported_rpc_commands.end();
+        if (!supported_rpc_command) {
+            std::cerr << "Error: Unknown RPC command \"" << rpc_command << "\" found in RPC_COMMANDS_NOT_SAFE_FOR_FUZZING. Please update " << __FILE__ << ".\n";
+            std::terminate();
+        }
+    }
+    const char* limit_to_rpc_command_env = std::getenv("LIMIT_TO_RPC_COMMAND");
+    if (limit_to_rpc_command_env != nullptr) {
+        g_limit_to_rpc_command = std::string{limit_to_rpc_command_env};
+    }
+}
+
+FUZZ_TARGET_INIT(rpc, initialize_rpc)
+{
+    FuzzedDataProvider fuzzed_data_provider{buffer.data(), buffer.size()};
+    SetMockTime(ConsumeTime(fuzzed_data_provider));
+    const std::string rpc_command = fuzzed_data_provider.ConsumeRandomLengthString(64);
+    if (!g_limit_to_rpc_command.empty() && rpc_command != g_limit_to_rpc_command) {
+        return;
+    }
+    const bool safe_for_fuzzing = std::find(RPC_COMMANDS_SAFE_FOR_FUZZING.begin(), RPC_COMMANDS_SAFE_FOR_FUZZING.end(), rpc_command) != RPC_COMMANDS_SAFE_FOR_FUZZING.end();
+    if (!safe_for_fuzzing) {
+        return;
+    }
+    std::vector<std::string> arguments;
+    while (fuzzed_data_provider.ConsumeBool()) {
+        arguments.push_back(ConsumeRPCArgument(fuzzed_data_provider));
+    }
+    try {
+        rpc_testing_setup->CallRPC(rpc_command, arguments);
+    } catch (const UniValue&) {
+    } catch (const std::runtime_error&) {
+    }
+}