Error if copying into the source directory. (DDoSolitary#122)

LxRunOffline/error.cpp

@@ -53,7 +53,8 @@ const wstr msg_table[] = {
 	L"Failed to detect filesystem version of the directory \"%1%\".",
 	L"Installing to the root directory \"%1%\" is known to cause issues.",
 	L"The configuration flags are invalid.",
-	L"The action/argument \"%1%\" doesn't support WSL2."
+	L"The action/argument \"%1%\" doesn't support WSL2.",
+	L"Copying or moving into a subdirectory of the source directory is not allowed."
 };
 
 lro_error::lro_error(const err_msg msg_code, std::vector<wstr> msg_args, const HRESULT err_code)

LxRunOffline/error.h

@@ -53,7 +53,8 @@ enum class err_msg {
 	err_fs_detect,
 	err_root_dir,
 	err_invalid_flags,
-	err_wsl2_unsupported
+	err_wsl2_unsupported,
+	err_copy_subdir
 };
 
 class lro_error : public std::exception {

LxRunOffline/fs.cpp

@@ -272,6 +272,10 @@ void archive_writer::write_hard_link() {
 	archive_entry_clear(pe.get());
 }
 
+bool archive_writer::check_source_path(const file_path &sp) const {
+	return true;
+}
+
 wsl_writer::wsl_writer() : hf_data(nullptr) {}
 
 void wsl_writer::write_data(HANDLE hf, const char *buf, const uint32_t size) const {
@@ -320,6 +324,11 @@ void wsl_writer::write_hard_link() {
 	}
 }
 
+bool wsl_writer::check_source_path(const file_path &sp) const {
+	// base_len of a linux_path is always 0, so it will be safely ignored.
+	return path->data.compare(0, std::min(path->base_len, sp.base_len), sp.data, 0, sp.base_len);
+}
+
 wsl_v1_writer::wsl_v1_writer(crwstr base_path) {
 	path = std::make_unique<wsl_v1_path>(base_path);
 	target_path = std::make_unique<wsl_v1_path>(base_path);
@@ -547,6 +556,13 @@ void wsl_reader::run(fs_writer &writer) {
 	});
 }
 
+void wsl_reader::run_checked(fs_writer &writer) {
+	if (!writer.check_source_path(*path)) {
+		throw lro_error::from_other(err_msg::err_copy_subdir, {});
+	}
+	run(writer);
+}
+
 wsl_v1_reader::wsl_v1_reader(crwstr base) {
 	path = std::make_unique<wsl_v1_path>(base);
 }

LxRunOffline/fs.h

@@ -22,6 +22,7 @@ class fs_writer {
 	virtual void write_directory(const file_attr *) = 0;
 	virtual void write_symlink(const file_attr *, const char *) = 0;
 	virtual void write_hard_link() = 0;
+	virtual bool check_source_path(const file_path &) const = 0;
 };
 
 class archive_writer : public fs_writer {
@@ -38,6 +39,7 @@ class archive_writer : public fs_writer {
 	void write_directory(const file_attr *) override;
 	void write_symlink(const file_attr *, const char *) override;
 	void write_hard_link() override;
+	bool check_source_path(const file_path &) const override;
 };
 
 class wsl_writer : public fs_writer {
@@ -53,6 +55,7 @@ class wsl_writer : public fs_writer {
 	void write_directory(const file_attr *) override;
 	void write_symlink(const file_attr *, const char *) override;
 	void write_hard_link() override;
+	bool check_source_path(const file_path &) const override;
 };
 
 class wsl_v1_writer : public wsl_writer {
@@ -101,6 +104,7 @@ class wsl_reader : public fs_reader {
 	virtual bool is_legacy() const;
 public:
 	void run(fs_writer &) override;
+	void run_checked(fs_writer &);
 };
 
 class wsl_v1_reader : public wsl_reader {

LxRunOffline/main.cpp

@@ -118,7 +118,7 @@ int wmain(int argc, wchar_t **argv) {
 			if (!move_directory(sp, dir)) {
 				auto ver = get_distro_version(name);
 				auto writer = select_wsl_writer(ver, dir);
-				select_wsl_reader(ver, sp)->run(*writer);
+				select_wsl_reader(ver, sp)->run_checked(*writer);
 				delete_directory(sp);
 			}
 			set_distro_dir(name, dir);
@@ -142,7 +142,7 @@ int wmain(int argc, wchar_t **argv) {
 			register_distro(new_name, dir, nv);
 			conf.configure_distro(new_name, config_all);
 			auto writer = select_wsl_writer(nv, dir);
-			select_wsl_reader(ov, get_distro_dir(name))->run(*writer);
+			select_wsl_reader(ov, get_distro_dir(name))->run_checked(*writer);
 		} else if (!wcscmp(argv[1], L"e") || !wcscmp(argv[1], L"export")) {
 			wstr file;
 			desc.add_options()(",f", po::wvalue<wstr>(&file)->required(), "Path to the .tar.gz file to export to. A config file will also be exported to this file name with a .xml extension.");

LxRunOffline/path.h

@@ -20,9 +20,9 @@ class prefix_matcher {
 
 class file_path {
 protected:
-	size_t base_len;
 	explicit file_path(crwstr);
 public:
+	size_t base_len;
 	wstr data;
 	virtual ~file_path() = default;
 	virtual bool append(wchar_t) = 0;