Merge bitcoin/bitcoin#22937: refactor: Forbid calling unsafe fs::path(std::string) constructor and fs::path::string() method

6544ea5035268025207d2402db2f7d90fde947a6 refactor: Block unsafe fs::path std::string conversion calls (Russell Yanofsky)
b39a477ec69a51b2016d3a8c70c0c77670f87f2b refactor: Add fs::PathToString, fs::PathFromString, u8string, u8path functions (Russell Yanofsky)

Pull request description:

  The `fs::path` class has a `std::string` constructor which will implicitly convert from strings. Implicit conversions like this are not great in general because they can hide complexity and inefficiencies in the code, but this case is especially bad, because after the transition from `boost::filesystem` to `std::filesystem` in #20744 the behavior of this constructor on windows will be more complicated and can mangle path strings. The `fs::path` class also has a `.string()` method which is inverse of the constructor and has the same problems.

  Fix this by replacing the unsafe method calls with `PathToString` and `PathFromString` function calls, and by forbidding unsafe method calls in the future.

ACKs for top commit:
  kiminuo:
    ACK 6544ea5035268025207d2402db2f7d90fde947a6
  laanwj:
    Code review ACK 6544ea5035268025207d2402db2f7d90fde947a6
  hebasto:
    re-ACK 6544ea5035268025207d2402db2f7d90fde947a6, only added `fsbridge_stem` test case, updated comment, and rebased since my [previous](https://github.com/bitcoin/bitcoin/pull/22937#pullrequestreview-765503126) review. Verified with the following command:

Tree-SHA512: c36324740eb4ee55151146626166c00d5ccc4b6f3df777e75c112bcb4d1db436c1d9cc8c29a1e7fb96051457d317961ab42e6c380c3be2771d135771b2b49fa0

17 files changed, 76 insertions, 83 deletions

diff --git a/src/wallet/bdb.cpp b/src/wallet/bdb.cpp
index 2eb4d3106c..2290e119fd 100644
--- a/src/wallet/bdb.cpp
+++ b/src/wallet/bdb.cpp
@@ -61,9 +61,9 @@ bool WalletDatabaseFileId::operator==(const WalletDatabaseFileId& rhs) const
 std::shared_ptr<BerkeleyEnvironment> GetBerkeleyEnv(const fs::path& env_directory)
 {
     LOCK(cs_db);
-    auto inserted = g_dbenvs.emplace(env_directory.string(), std::weak_ptr<BerkeleyEnvironment>());
+    auto inserted = g_dbenvs.emplace(fs::PathToString(env_directory), std::weak_ptr<BerkeleyEnvironment>());
     if (inserted.second) {
-        auto env = std::make_shared<BerkeleyEnvironment>(env_directory.string());
+        auto env = std::make_shared<BerkeleyEnvironment>(env_directory);
         inserted.first->second = env;
         return env;
     }
@@ -101,7 +101,7 @@ void BerkeleyEnvironment::Close()
 
     if (error_file) fclose(error_file);
 
-    UnlockDirectory(strPath, ".walletlock");
+    UnlockDirectory(fs::PathFromString(strPath), ".walletlock");
 }
 
 void BerkeleyEnvironment::Reset()
@@ -111,7 +111,7 @@ void BerkeleyEnvironment::Reset()
     fMockDb = false;
 }
 
-BerkeleyEnvironment::BerkeleyEnvironment(const fs::path& dir_path) : strPath(dir_path.string())
+BerkeleyEnvironment::BerkeleyEnvironment(const fs::path& dir_path) : strPath(fs::PathToString(dir_path))
 {
     Reset();
 }
@@ -129,24 +129,24 @@ bool BerkeleyEnvironment::Open(bilingual_str& err)
         return true;
     }
 
-    fs::path pathIn = strPath;
+    fs::path pathIn = fs::PathFromString(strPath);
     TryCreateDirectories(pathIn);
     if (!LockDirectory(pathIn, ".walletlock")) {
         LogPrintf("Cannot obtain a lock on wallet directory %s. Another instance of bitcoin may be using it.\n", strPath);
-        err = strprintf(_("Error initializing wallet database environment %s!"), Directory());
+        err = strprintf(_("Error initializing wallet database environment %s!"), fs::quoted(fs::PathToString(Directory())));
         return false;
     }
 
     fs::path pathLogDir = pathIn / "database";
     TryCreateDirectories(pathLogDir);
     fs::path pathErrorFile = pathIn / "db.log";
-    LogPrintf("BerkeleyEnvironment::Open: LogDir=%s ErrorFile=%s\n", pathLogDir.string(), pathErrorFile.string());
+    LogPrintf("BerkeleyEnvironment::Open: LogDir=%s ErrorFile=%s\n", fs::PathToString(pathLogDir), fs::PathToString(pathErrorFile));
 
     unsigned int nEnvFlags = 0;
     if (gArgs.GetBoolArg("-privdb", DEFAULT_WALLET_PRIVDB))
         nEnvFlags |= DB_PRIVATE;
 
-    dbenv->set_lg_dir(pathLogDir.string().c_str());
+    dbenv->set_lg_dir(fs::PathToString(pathLogDir).c_str());
     dbenv->set_cachesize(0, 0x100000, 1); // 1 MiB should be enough for just the wallet
     dbenv->set_lg_bsize(0x10000);
     dbenv->set_lg_max(1048576);
@@ -173,7 +173,7 @@ bool BerkeleyEnvironment::Open(bilingual_str& err)
             LogPrintf("BerkeleyEnvironment::Open: Error %d closing failed database environment: %s\n", ret2, DbEnv::strerror(ret2));
         }
         Reset();
-        err = strprintf(_("Error initializing wallet database environment %s!"), Directory());
+        err = strprintf(_("Error initializing wallet database environment %s!"), fs::quoted(fs::PathToString(Directory())));
         if (ret == DB_RUNRECOVERY) {
             err += Untranslated(" ") + _("This error could occur if this wallet was not shutdown cleanly and was last loaded using a build with a newer version of Berkeley DB. If so, please use the software that last loaded this wallet");
         }
@@ -261,7 +261,7 @@ bool BerkeleyDatabase::Verify(bilingual_str& errorStr)
     fs::path file_path = walletDir / strFile;
 
     LogPrintf("Using BerkeleyDB version %s\n", BerkeleyDatabaseVersion());
-    LogPrintf("Using wallet %s\n", file_path.string());
+    LogPrintf("Using wallet %s\n", fs::PathToString(file_path));
 
     if (!env->Open(errorStr)) {
         return false;
@@ -274,7 +274,7 @@ bool BerkeleyDatabase::Verify(bilingual_str& errorStr)
         Db db(env->dbenv.get(), 0);
         int result = db.verify(strFile.c_str(), nullptr, nullptr, 0);
         if (result != 0) {
-            errorStr = strprintf(_("%s corrupt. Try using the wallet tool bitcoin-wallet to salvage or restoring a backup."), file_path);
+            errorStr = strprintf(_("%s corrupt. Try using the wallet tool bitcoin-wallet to salvage or restoring a backup."), fs::quoted(fs::PathToString(file_path)));
             return false;
         }
     }
@@ -566,7 +566,7 @@ void BerkeleyEnvironment::Flush(bool fShutdown)
                 dbenv->log_archive(&listp, DB_ARCH_REMOVE);
                 Close();
                 if (!fMockDb) {
-                    fs::remove_all(fs::path(strPath) / "database");
+                    fs::remove_all(fs::PathFromString(strPath) / "database");
                 }
             }
         }
@@ -614,21 +614,21 @@ bool BerkeleyDatabase::Backup(const std::string& strDest) const
 
                 // Copy wallet file
                 fs::path pathSrc = env->Directory() / strFile;
-                fs::path pathDest(strDest);
+                fs::path pathDest(fs::PathFromString(strDest));
                 if (fs::is_directory(pathDest))
-                    pathDest /= strFile;
+                    pathDest /= fs::PathFromString(strFile);
 
                 try {
                     if (fs::equivalent(pathSrc, pathDest)) {
-                        LogPrintf("cannot backup to wallet source file %s\n", pathDest.string());
+                        LogPrintf("cannot backup to wallet source file %s\n", fs::PathToString(pathDest));
                         return false;
                     }
 
                     fs::copy_file(pathSrc, pathDest, fs::copy_option::overwrite_if_exists);
-                    LogPrintf("copied %s to %s\n", strFile, pathDest.string());
+                    LogPrintf("copied %s to %s\n", strFile, fs::PathToString(pathDest));
                     return true;
                 } catch (const fs::filesystem_error& e) {
-                    LogPrintf("error copying %s to %s - %s\n", strFile, pathDest.string(), fsbridge::get_filesystem_error_message(e));
+                    LogPrintf("error copying %s to %s - %s\n", strFile, fs::PathToString(pathDest), fsbridge::get_filesystem_error_message(e));
                     return false;
                 }
             }
@@ -828,10 +828,10 @@ std::unique_ptr<BerkeleyDatabase> MakeBerkeleyDatabase(const fs::path& path, con
     std::unique_ptr<BerkeleyDatabase> db;
     {
         LOCK(cs_db); // Lock env.m_databases until insert in BerkeleyDatabase constructor
-        std::string data_filename = data_file.filename().string();
+        std::string data_filename = fs::PathToString(data_file.filename());
         std::shared_ptr<BerkeleyEnvironment> env = GetBerkeleyEnv(data_file.parent_path());
         if (env->m_databases.count(data_filename)) {
-            error = Untranslated(strprintf("Refusing to load database. Data file '%s' is already loaded.", (env->Directory() / data_filename).string()));
+            error = Untranslated(strprintf("Refusing to load database. Data file '%s' is already loaded.", fs::PathToString(env->Directory() / data_filename)));
             status = DatabaseStatus::FAILED_ALREADY_LOADED;
             return nullptr;
         }
diff --git a/src/wallet/bdb.h b/src/wallet/bdb.h
index a8209587d7..b666a8e73a 100644
--- a/src/wallet/bdb.h
+++ b/src/wallet/bdb.h
@@ -63,7 +63,7 @@ public:
 
     bool IsMock() const { return fMockDb; }
     bool IsInitialized() const { return fDbEnvInit; }
-    fs::path Directory() const { return strPath; }
+    fs::path Directory() const { return fs::PathFromString(strPath); }
 
     bool Open(bilingual_str& error);
     void Close();
@@ -141,7 +141,7 @@ public:
     bool Verify(bilingual_str& error);
 
     /** Return path to main database filename */
-    std::string Filename() override { return (env->Directory() / strFile).string(); }
+    std::string Filename() override { return fs::PathToString(env->Directory() / strFile); }
 
     std::string Format() override { return "bdb"; }
     /**
diff --git a/src/wallet/db.cpp b/src/wallet/db.cpp
index 8d5316e0af..c74c69ed09 100644
--- a/src/wallet/db.cpp
+++ b/src/wallet/db.cpp
@@ -12,7 +12,7 @@
 
 std::vector<fs::path> ListDatabases(const fs::path& wallet_dir)
 {
-    const size_t offset = wallet_dir.string().size() + (wallet_dir == wallet_dir.root_name() ? 0 : 1);
+    const size_t offset = wallet_dir.native().size() + (wallet_dir == wallet_dir.root_name() ? 0 : 1);
     std::vector<fs::path> paths;
     boost::system::error_code ec;
 
@@ -20,9 +20,9 @@ std::vector<fs::path> ListDatabases(const fs::path& wallet_dir)
         if (ec) {
             if (fs::is_directory(*it)) {
                 it.no_push();
-                LogPrintf("%s: %s %s -- skipping.\n", __func__, ec.message(), it->path().string());
+                LogPrintf("%s: %s %s -- skipping.\n", __func__, ec.message(), fs::PathToString(it->path()));
             } else {
-                LogPrintf("%s: %s %s\n", __func__, ec.message(), it->path().string());
+                LogPrintf("%s: %s %s\n", __func__, ec.message(), fs::PathToString(it->path()));
             }
             continue;
         }
@@ -30,7 +30,8 @@ std::vector<fs::path> ListDatabases(const fs::path& wallet_dir)
         try {
             // Get wallet path relative to walletdir by removing walletdir from the wallet path.
             // This can be replaced by boost::filesystem::lexically_relative once boost is bumped to 1.60.
-            const fs::path path = it->path().string().substr(offset);
+            const auto path_str = it->path().native().substr(offset);
+            const fs::path path{path_str.begin(), path_str.end()};
 
             if (it->status().type() == fs::directory_file &&
                 (IsBDBFile(BDBDataFile(it->path())) || IsSQLiteFile(SQLiteDataFile(it->path())))) {
@@ -50,7 +51,7 @@ std::vector<fs::path> ListDatabases(const fs::path& wallet_dir)
                 }
             }
         } catch (const std::exception& e) {
-            LogPrintf("%s: Error scanning %s: %s\n", __func__, it->path().string(), e.what());
+            LogPrintf("%s: Error scanning %s: %s\n", __func__, fs::PathToString(it->path()), e.what());
             it.no_push();
         }
     }
@@ -85,7 +86,7 @@ bool IsBDBFile(const fs::path& path)
     // This check also prevents opening lock files.
     boost::system::error_code ec;
     auto size = fs::file_size(path, ec);
-    if (ec) LogPrintf("%s: %s %s\n", __func__, ec.message(), path.string());
+    if (ec) LogPrintf("%s: %s %s\n", __func__, ec.message(), fs::PathToString(path));
     if (size < 4096) return false;
 
     fsbridge::ifstream file(path, std::ios::binary);
@@ -109,7 +110,7 @@ bool IsSQLiteFile(const fs::path& path)
     // A SQLite Database file is at least 512 bytes.
     boost::system::error_code ec;
     auto size = fs::file_size(path, ec);
-    if (ec) LogPrintf("%s: %s %s\n", __func__, ec.message(), path.string());
+    if (ec) LogPrintf("%s: %s %s\n", __func__, ec.message(), fs::PathToString(path));
     if (size < 512) return false;
 
     fsbridge::ifstream file(path, std::ios::binary);
diff --git a/src/wallet/dump.cpp b/src/wallet/dump.cpp
index c39c0c7e73..08d94b76d9 100644
--- a/src/wallet/dump.cpp
+++ b/src/wallet/dump.cpp
@@ -19,16 +19,16 @@ bool DumpWallet(CWallet& wallet, bilingual_str& error)
         return false;
     }
 
-    fs::path path = dump_filename;
+    fs::path path = fs::PathFromString(dump_filename);
     path = fs::absolute(path);
     if (fs::exists(path)) {
-        error = strprintf(_("File %s already exists. If you are sure this is what you want, move it out of the way first."), path.string());
+        error = strprintf(_("File %s already exists. If you are sure this is what you want, move it out of the way first."), fs::PathToString(path));
         return false;
     }
     fsbridge::ofstream dump_file;
     dump_file.open(path);
     if (dump_file.fail()) {
-        error = strprintf(_("Unable to open %s for writing"), path.string());
+        error = strprintf(_("Unable to open %s for writing"), fs::PathToString(path));
         return false;
     }
 
@@ -114,10 +114,10 @@ bool CreateFromDump(const std::string& name, const fs::path& wallet_path, biling
         return false;
     }
 
-    fs::path dump_path = dump_filename;
+    fs::path dump_path = fs::PathFromString(dump_filename);
     dump_path = fs::absolute(dump_path);
     if (!fs::exists(dump_path)) {
-        error = strprintf(_("Dump file %s does not exist."), dump_path.string());
+        error = strprintf(_("Dump file %s does not exist."), fs::PathToString(dump_path));
         return false;
     }
     fsbridge::ifstream dump_file(dump_path);
diff --git a/src/wallet/interfaces.cpp b/src/wallet/interfaces.cpp
index 7d0cdb6934..57f1a6a67a 100644
--- a/src/wallet/interfaces.cpp
+++ b/src/wallet/interfaces.cpp
@@ -551,13 +551,13 @@ public:
     }
     std::string getWalletDir() override
     {
-        return GetWalletDir().string();
+        return fs::PathToString(GetWalletDir());
     }
     std::vector<std::string> listWalletDir() override
     {
         std::vector<std::string> paths;
         for (auto& path : ListDatabases(GetWalletDir())) {
-            paths.push_back(path.string());
+            paths.push_back(fs::PathToString(path));
         }
         return paths;
     }
diff --git a/src/wallet/load.cpp b/src/wallet/load.cpp
index 1b841026b8..7ef5a0cf55 100644
--- a/src/wallet/load.cpp
+++ b/src/wallet/load.cpp
@@ -25,25 +25,25 @@ bool VerifyWallets(WalletContext& context)
     ArgsManager& args = *Assert(context.args);
 
     if (args.IsArgSet("-walletdir")) {
-        fs::path wallet_dir = args.GetArg("-walletdir", "");
+        fs::path wallet_dir = fs::PathFromString(args.GetArg("-walletdir", ""));
         boost::system::error_code error;
         // The canonical path cleans the path, preventing >1 Berkeley environment instances for the same directory
         fs::path canonical_wallet_dir = fs::canonical(wallet_dir, error);
         if (error || !fs::exists(wallet_dir)) {
-            chain.initError(strprintf(_("Specified -walletdir \"%s\" does not exist"), wallet_dir.string()));
+            chain.initError(strprintf(_("Specified -walletdir \"%s\" does not exist"), fs::PathToString(wallet_dir)));
             return false;
         } else if (!fs::is_directory(wallet_dir)) {
-            chain.initError(strprintf(_("Specified -walletdir \"%s\" is not a directory"), wallet_dir.string()));
+            chain.initError(strprintf(_("Specified -walletdir \"%s\" is not a directory"), fs::PathToString(wallet_dir)));
             return false;
         // The canonical path transforms relative paths into absolute ones, so we check the non-canonical version
         } else if (!wallet_dir.is_absolute()) {
-            chain.initError(strprintf(_("Specified -walletdir \"%s\" is a relative path"), wallet_dir.string()));
+            chain.initError(strprintf(_("Specified -walletdir \"%s\" is a relative path"), fs::PathToString(wallet_dir)));
             return false;
         }
-        args.ForceSetArg("-walletdir", canonical_wallet_dir.string());
+        args.ForceSetArg("-walletdir", fs::PathToString(canonical_wallet_dir));
     }
 
-    LogPrintf("Using wallet directory %s\n", GetWalletDir().string());
+    LogPrintf("Using wallet directory %s\n", fs::PathToString(GetWalletDir()));
 
     chain.initMessage(_("Verifying wallet(s)…").translated);
 
@@ -70,7 +70,7 @@ bool VerifyWallets(WalletContext& context)
 
     for (const auto& wallet : chain.getSettingsList("wallet")) {
         const auto& wallet_file = wallet.get_str();
-        const fs::path path = fsbridge::AbsPathJoin(GetWalletDir(), wallet_file);
+        const fs::path path = fsbridge::AbsPathJoin(GetWalletDir(), fs::PathFromString(wallet_file));
 
         if (!wallet_paths.insert(path).second) {
             chain.initWarning(strprintf(_("Ignoring duplicate -wallet %s."), wallet_file));
@@ -102,7 +102,7 @@ bool LoadWallets(WalletContext& context)
         std::set<fs::path> wallet_paths;
         for (const auto& wallet : chain.getSettingsList("wallet")) {
             const auto& name = wallet.get_str();
-            if (!wallet_paths.insert(name).second) {
+            if (!wallet_paths.insert(fs::PathFromString(name)).second) {
                 continue;
             }
             DatabaseOptions options;
diff --git a/src/wallet/rpcdump.cpp b/src/wallet/rpcdump.cpp
index 4d7fb2d38c..9b09bc23d6 100644
--- a/src/wallet/rpcdump.cpp
+++ b/src/wallet/rpcdump.cpp
@@ -550,7 +550,7 @@ RPCHelpMan importwallet()
         EnsureWalletIsUnlocked(*pwallet);
 
         fsbridge::ifstream file;
-        file.open(request.params[0].get_str(), std::ios::in | std::ios::ate);
+        file.open(fs::u8path(request.params[0].get_str()), std::ios::in | std::ios::ate);
         if (!file.is_open()) {
             throw JSONRPCError(RPC_INVALID_PARAMETER, "Cannot open wallet dump file");
         }
@@ -745,7 +745,7 @@ RPCHelpMan dumpwallet()
 
     EnsureWalletIsUnlocked(wallet);
 
-    fs::path filepath = request.params[0].get_str();
+    fs::path filepath = fs::u8path(request.params[0].get_str());
     filepath = fs::absolute(filepath);
 
     /* Prevent arbitrary files from being overwritten. There have been reports
@@ -754,7 +754,7 @@ RPCHelpMan dumpwallet()
      * It may also avoid other security issues.
      */
     if (fs::exists(filepath)) {
-        throw JSONRPCError(RPC_INVALID_PARAMETER, filepath.string() + " already exists. If you are sure this is what you want, move it out of the way first");
+        throw JSONRPCError(RPC_INVALID_PARAMETER, filepath.u8string() + " already exists. If you are sure this is what you want, move it out of the way first");
     }
 
     fsbridge::ofstream file;
@@ -844,7 +844,7 @@ RPCHelpMan dumpwallet()
     file.close();
 
     UniValue reply(UniValue::VOBJ);
-    reply.pushKV("filename", filepath.string());
+    reply.pushKV("filename", filepath.u8string());
 
     return reply;
 },
diff --git a/src/wallet/rpcwallet.cpp b/src/wallet/rpcwallet.cpp
index 9d86ec4810..6959466d1d 100644
--- a/src/wallet/rpcwallet.cpp
+++ b/src/wallet/rpcwallet.cpp
@@ -2582,7 +2582,7 @@ static RPCHelpMan listwalletdir()
     UniValue wallets(UniValue::VARR);
     for (const auto& path : ListDatabases(GetWalletDir())) {
         UniValue wallet(UniValue::VOBJ);
-        wallet.pushKV("name", path.string());
+        wallet.pushKV("name", path.u8string());
         wallets.push_back(wallet);
     }
 
@@ -2883,7 +2883,7 @@ static RPCHelpMan restorewallet()
 
     WalletContext& context = EnsureWalletContext(request.context);
 
-    std::string backup_file = request.params[1].get_str();
+    auto backup_file = fs::u8path(request.params[1].get_str());
 
     if (!fs::exists(backup_file)) {
         throw JSONRPCError(RPC_INVALID_PARAMETER, "Backup file does not exist");
@@ -2891,14 +2891,14 @@ static RPCHelpMan restorewallet()
 
     std::string wallet_name = request.params[0].get_str();
 
-    const fs::path wallet_path = fsbridge::AbsPathJoin(GetWalletDir(), wallet_name);
+    const fs::path wallet_path = fsbridge::AbsPathJoin(GetWalletDir(), fs::u8path(wallet_name));
 
     if (fs::exists(wallet_path)) {
         throw JSONRPCError(RPC_INVALID_PARAMETER, "Wallet name already exists.");
     }
 
     if (!TryCreateDirectories(wallet_path)) {
-        throw JSONRPCError(RPC_WALLET_ERROR, strprintf("Failed to create database path '%s'. Database already exists.", wallet_path.string()));
+        throw JSONRPCError(RPC_WALLET_ERROR, strprintf("Failed to create database path '%s'. Database already exists.", wallet_path.u8string()));
     }
 
     auto wallet_file = wallet_path / "wallet.dat";
diff --git a/src/wallet/sqlite.cpp b/src/wallet/sqlite.cpp
index 815d17967c..650e083e8e 100644
--- a/src/wallet/sqlite.cpp
+++ b/src/wallet/sqlite.cpp
@@ -67,7 +67,7 @@ static void SetPragma(sqlite3* db, const std::string& key, const std::string& va
 }
 
 SQLiteDatabase::SQLiteDatabase(const fs::path& dir_path, const fs::path& file_path, bool mock)
-    : WalletDatabase(), m_mock(mock), m_dir_path(dir_path.string()), m_file_path(file_path.string())
+    : WalletDatabase(), m_mock(mock), m_dir_path(fs::PathToString(dir_path)), m_file_path(fs::PathToString(file_path))
 {
     {
         LOCK(g_sqlite_mutex);
@@ -206,7 +206,7 @@ void SQLiteDatabase::Open()
 
     if (m_db == nullptr) {
         if (!m_mock) {
-            TryCreateDirectories(m_dir_path);
+            TryCreateDirectories(fs::PathFromString(m_dir_path));
         }
         int ret = sqlite3_open_v2(m_file_path.c_str(), &m_db, flags, nullptr);
         if (ret != SQLITE_OK) {
diff --git a/src/wallet/test/db_tests.cpp b/src/wallet/test/db_tests.cpp
index 16cb7e0baf..dba3f35025 100644
--- a/src/wallet/test/db_tests.cpp
+++ b/src/wallet/test/db_tests.cpp
@@ -16,7 +16,7 @@ BOOST_FIXTURE_TEST_SUITE(db_tests, BasicTestingSetup)
 static std::shared_ptr<BerkeleyEnvironment> GetWalletEnv(const fs::path& path, std::string& database_filename)
 {
     fs::path data_file = BDBDataFile(path);
-    database_filename = data_file.filename().string();
+    database_filename = fs::PathToString(data_file.filename());
     return GetBerkeleyEnv(data_file.parent_path());
 }
 
@@ -25,11 +25,7 @@ BOOST_AUTO_TEST_CASE(getwalletenv_file)
     std::string test_name = "test_name.dat";
     const fs::path datadir = gArgs.GetDataDirNet();
     fs::path file_path = datadir / test_name;
-#if BOOST_VERSION >= 107700
-    std::ofstream f(BOOST_FILESYSTEM_C_STR(file_path));
-#else
-    std::ofstream f(file_path.BOOST_FILESYSTEM_C_STR);
-#endif // BOOST_VERSION >= 107700
+    fs::ofstream f(file_path);
     f.close();
 
     std::string filename;
diff --git a/src/wallet/test/init_test_fixture.cpp b/src/wallet/test/init_test_fixture.cpp
index 53c972c46d..170675c035 100644
--- a/src/wallet/test/init_test_fixture.cpp
+++ b/src/wallet/test/init_test_fixture.cpp
@@ -32,11 +32,7 @@ InitWalletDirTestingSetup::InitWalletDirTestingSetup(const std::string& chainNam
     fs::create_directories(m_walletdir_path_cases["default"]);
     fs::create_directories(m_walletdir_path_cases["custom"]);
     fs::create_directories(m_walletdir_path_cases["relative"]);
-#if BOOST_VERSION >= 107700
-    std::ofstream f(BOOST_FILESYSTEM_C_STR(m_walletdir_path_cases["file"]));
-#else
-    std::ofstream f(m_walletdir_path_cases["file"].BOOST_FILESYSTEM_C_STR);
-#endif // BOOST_VERSION >= 107700
+    fs::ofstream f(m_walletdir_path_cases["file"]);
     f.close();
 }
 
@@ -50,5 +46,5 @@ InitWalletDirTestingSetup::~InitWalletDirTestingSetup()
 
 void InitWalletDirTestingSetup::SetWalletDir(const fs::path& walletdir_path)
 {
-    gArgs.ForceSetArg("-walletdir", walletdir_path.string());
+    gArgs.ForceSetArg("-walletdir", fs::PathToString(walletdir_path));
 }
diff --git a/src/wallet/test/init_tests.cpp b/src/wallet/test/init_tests.cpp
index 45e1b8c4b8..222c2bf4b7 100644
--- a/src/wallet/test/init_tests.cpp
+++ b/src/wallet/test/init_tests.cpp
@@ -17,7 +17,7 @@ BOOST_AUTO_TEST_CASE(walletinit_verify_walletdir_default)
     SetWalletDir(m_walletdir_path_cases["default"]);
     bool result = m_wallet_client->verify();
     BOOST_CHECK(result == true);
-    fs::path walletdir = gArgs.GetArg("-walletdir", "");
+    fs::path walletdir = fs::PathFromString(gArgs.GetArg("-walletdir", ""));
     fs::path expected_path = fs::canonical(m_walletdir_path_cases["default"]);
     BOOST_CHECK_EQUAL(walletdir, expected_path);
 }
@@ -27,7 +27,7 @@ BOOST_AUTO_TEST_CASE(walletinit_verify_walletdir_custom)
     SetWalletDir(m_walletdir_path_cases["custom"]);
     bool result = m_wallet_client->verify();
     BOOST_CHECK(result == true);
-    fs::path walletdir = gArgs.GetArg("-walletdir", "");
+    fs::path walletdir = fs::PathFromString(gArgs.GetArg("-walletdir", ""));
     fs::path expected_path = fs::canonical(m_walletdir_path_cases["custom"]);
     BOOST_CHECK_EQUAL(walletdir, expected_path);
 }
@@ -67,7 +67,7 @@ BOOST_AUTO_TEST_CASE(walletinit_verify_walletdir_no_trailing)
     SetWalletDir(m_walletdir_path_cases["trailing"]);
     bool result = m_wallet_client->verify();
     BOOST_CHECK(result == true);
-    fs::path walletdir = gArgs.GetArg("-walletdir", "");
+    fs::path walletdir = fs::PathFromString(gArgs.GetArg("-walletdir", ""));
     fs::path expected_path = fs::canonical(m_walletdir_path_cases["default"]);
     BOOST_CHECK_EQUAL(walletdir, expected_path);
 }
@@ -77,7 +77,7 @@ BOOST_AUTO_TEST_CASE(walletinit_verify_walletdir_no_trailing2)
     SetWalletDir(m_walletdir_path_cases["trailing2"]);
     bool result = m_wallet_client->verify();
     BOOST_CHECK(result == true);
-    fs::path walletdir = gArgs.GetArg("-walletdir", "");
+    fs::path walletdir = fs::PathFromString(gArgs.GetArg("-walletdir", ""));
     fs::path expected_path = fs::canonical(m_walletdir_path_cases["default"]);
     BOOST_CHECK_EQUAL(walletdir, expected_path);
 }
diff --git a/src/wallet/test/wallet_tests.cpp b/src/wallet/test/wallet_tests.cpp
index 9938380369..94b5abfba7 100644
--- a/src/wallet/test/wallet_tests.cpp
+++ b/src/wallet/test/wallet_tests.cpp
@@ -258,7 +258,7 @@ BOOST_FIXTURE_TEST_CASE(importwallet_rescan, TestChain100Setup)
     SetMockTime(KEY_TIME);
     m_coinbase_txns.emplace_back(CreateAndProcessBlock({}, GetScriptForRawPubKey(coinbaseKey.GetPubKey())).vtx[0]);
 
-    std::string backup_file = (gArgs.GetDataDirNet() / "wallet.backup").string();
+    std::string backup_file = fs::PathToString(gArgs.GetDataDirNet() / "wallet.backup");
 
     // Import key into wallet and call dumpwallet to create backup file.
     {
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index abfe9d7dba..598fce0112 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -2515,16 +2515,16 @@ std::unique_ptr<WalletDatabase> MakeWalletDatabase(const std::string& name, cons
     // 2. Path to an existing directory.
     // 3. Path to a symlink to a directory.
     // 4. For backwards compatibility, the name of a data file in -walletdir.
-    const fs::path wallet_path = fsbridge::AbsPathJoin(GetWalletDir(), name);
+    const fs::path wallet_path = fsbridge::AbsPathJoin(GetWalletDir(), fs::PathFromString(name));
     fs::file_type path_type = fs::symlink_status(wallet_path).type();
     if (!(path_type == fs::file_not_found || path_type == fs::directory_file ||
           (path_type == fs::symlink_file && fs::is_directory(wallet_path)) ||
-          (path_type == fs::regular_file && fs::path(name).filename() == name))) {
+          (path_type == fs::regular_file && fs::PathFromString(name).filename() == fs::PathFromString(name)))) {
         error_string = Untranslated(strprintf(
               "Invalid -wallet path '%s'. -wallet path should point to a directory where wallet.dat and "
               "database/log.?????????? files can be stored, a location where such a directory could be created, "
               "or (for backwards compatibility) the name of an existing data file in -walletdir (%s)",
-              name, GetWalletDir()));
+              name, fs::quoted(fs::PathToString(GetWalletDir()))));
         status = DatabaseStatus::FAILED_BAD_PATH;
         return nullptr;
     }
diff --git a/src/wallet/walletdb.cpp b/src/wallet/walletdb.cpp
index 8ff09a0878..a6839f1f78 100644
--- a/src/wallet/walletdb.cpp
+++ b/src/wallet/walletdb.cpp
@@ -1106,7 +1106,7 @@ std::unique_ptr<WalletDatabase> MakeDatabase(const fs::path& path, const Databas
     try {
         exists = fs::symlink_status(path).type() != fs::file_not_found;
     } catch (const fs::filesystem_error& e) {
-        error = Untranslated(strprintf("Failed to access database path '%s': %s", path.string(), fsbridge::get_filesystem_error_message(e)));
+        error = Untranslated(strprintf("Failed to access database path '%s': %s", fs::PathToString(path), fsbridge::get_filesystem_error_message(e)));
         status = DatabaseStatus::FAILED_BAD_PATH;
         return nullptr;
     }
@@ -1118,33 +1118,33 @@ std::unique_ptr<WalletDatabase> MakeDatabase(const fs::path& path, const Databas
         }
         if (IsSQLiteFile(SQLiteDataFile(path))) {
             if (format) {
-                error = Untranslated(strprintf("Failed to load database path '%s'. Data is in ambiguous format.", path.string()));
+                error = Untranslated(strprintf("Failed to load database path '%s'. Data is in ambiguous format.", fs::PathToString(path)));
                 status = DatabaseStatus::FAILED_BAD_FORMAT;
                 return nullptr;
             }
             format = DatabaseFormat::SQLITE;
         }
     } else if (options.require_existing) {
-        error = Untranslated(strprintf("Failed to load database path '%s'. Path does not exist.", path.string()));
+        error = Untranslated(strprintf("Failed to load database path '%s'. Path does not exist.", fs::PathToString(path)));
         status = DatabaseStatus::FAILED_NOT_FOUND;
         return nullptr;
     }
 
     if (!format && options.require_existing) {
-        error = Untranslated(strprintf("Failed to load database path '%s'. Data is not in recognized format.", path.string()));
+        error = Untranslated(strprintf("Failed to load database path '%s'. Data is not in recognized format.", fs::PathToString(path)));
         status = DatabaseStatus::FAILED_BAD_FORMAT;
         return nullptr;
     }
 
     if (format && options.require_create) {
-        error = Untranslated(strprintf("Failed to create database path '%s'. Database already exists.", path.string()));
+        error = Untranslated(strprintf("Failed to create database path '%s'. Database already exists.", fs::PathToString(path)));
         status = DatabaseStatus::FAILED_ALREADY_EXISTS;
         return nullptr;
     }
 
     // A db already exists so format is set, but options also specifies the format, so make sure they agree
     if (format && options.require_format && format != options.require_format) {
-        error = Untranslated(strprintf("Failed to load database path '%s'. Data is not in required format.", path.string()));
+        error = Untranslated(strprintf("Failed to load database path '%s'. Data is not in required format.", fs::PathToString(path)));
         status = DatabaseStatus::FAILED_BAD_FORMAT;
         return nullptr;
     }
@@ -1166,7 +1166,7 @@ std::unique_ptr<WalletDatabase> MakeDatabase(const fs::path& path, const Databas
 #ifdef USE_SQLITE
         return MakeSQLiteDatabase(path, options, status, error);
 #endif
-        error = Untranslated(strprintf("Failed to open database path '%s'. Build does not support SQLite database format.", path.string()));
+        error = Untranslated(strprintf("Failed to open database path '%s'. Build does not support SQLite database format.", fs::PathToString(path)));
         status = DatabaseStatus::FAILED_BAD_FORMAT;
         return nullptr;
     }
@@ -1174,7 +1174,7 @@ std::unique_ptr<WalletDatabase> MakeDatabase(const fs::path& path, const Databas
 #ifdef USE_BDB
     return MakeBerkeleyDatabase(path, options, status, error);
 #endif
-    error = Untranslated(strprintf("Failed to open database path '%s'. Build does not support Berkeley DB database format.", path.string()));
+    error = Untranslated(strprintf("Failed to open database path '%s'. Build does not support Berkeley DB database format.", fs::PathToString(path)));
     status = DatabaseStatus::FAILED_BAD_FORMAT;
     return nullptr;
 }
diff --git a/src/wallet/wallettool.cpp b/src/wallet/wallettool.cpp
index e3cb5cee5d..788679bbeb 100644
--- a/src/wallet/wallettool.cpp
+++ b/src/wallet/wallettool.cpp
@@ -125,7 +125,7 @@ bool ExecuteWalletToolFunc(const ArgsManager& args, const std::string& command)
         return false;
     }
     const std::string name = args.GetArg("-wallet", "");
-    const fs::path path = fsbridge::AbsPathJoin(GetWalletDir(), name);
+    const fs::path path = fsbridge::AbsPathJoin(GetWalletDir(), fs::PathFromString(name));
 
     if (command == "create") {
         DatabaseOptions options;
diff --git a/src/wallet/walletutil.cpp b/src/wallet/walletutil.cpp
index 1c518daba6..7f813432b3 100644
--- a/src/wallet/walletutil.cpp
+++ b/src/wallet/walletutil.cpp
@@ -12,7 +12,7 @@ fs::path GetWalletDir()
     fs::path path;
 
     if (gArgs.IsArgSet("-walletdir")) {
-        path = gArgs.GetArg("-walletdir", "");
+        path = fs::PathFromString(gArgs.GetArg("-walletdir", ""));
         if (!fs::is_directory(path)) {
             // If the path specified doesn't exist, we return the deliberately
             // invalid empty string.