initial commit, 4.5 stable

core/io/file_access_encrypted.cpp

@@ -0,0 +1,353 @@
+/**************************************************************************/
+/*  file_access_encrypted.cpp                                             */
+/**************************************************************************/
+/*                         This file is part of:                          */
+/*                             GODOT ENGINE                               */
+/*                        https://godotengine.org                         */
+/**************************************************************************/
+/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
+/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
+/*                                                                        */
+/* Permission is hereby granted, free of charge, to any person obtaining  */
+/* a copy of this software and associated documentation files (the        */
+/* "Software"), to deal in the Software without restriction, including    */
+/* without limitation the rights to use, copy, modify, merge, publish,    */
+/* distribute, sublicense, and/or sell copies of the Software, and to     */
+/* permit persons to whom the Software is furnished to do so, subject to  */
+/* the following conditions:                                              */
+/*                                                                        */
+/* The above copyright notice and this permission notice shall be         */
+/* included in all copies or substantial portions of the Software.        */
+/*                                                                        */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,        */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF     */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. */
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY   */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,   */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE      */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                 */
+/**************************************************************************/
+
+#include "file_access_encrypted.h"
+
+#include "core/variant/variant.h"
+
+CryptoCore::RandomGenerator *FileAccessEncrypted::_fae_static_rng = nullptr;
+
+void FileAccessEncrypted::deinitialize() {
+	if (_fae_static_rng) {
+		memdelete(_fae_static_rng);
+		_fae_static_rng = nullptr;
+	}
+}
+
+Error FileAccessEncrypted::open_and_parse(Ref<FileAccess> p_base, const Vector<uint8_t> &p_key, Mode p_mode, bool p_with_magic, const Vector<uint8_t> &p_iv) {
+	ERR_FAIL_COND_V_MSG(file.is_valid(), ERR_ALREADY_IN_USE, vformat("Can't open file while another file from path '%s' is open.", file->get_path_absolute()));
+	ERR_FAIL_COND_V(p_key.size() != 32, ERR_INVALID_PARAMETER);
+
+	pos = 0;
+	eofed = false;
+	use_magic = p_with_magic;
+
+	if (p_mode == MODE_WRITE_AES256) {
+		data.clear();
+		writing = true;
+		file = p_base;
+		key = p_key;
+		if (p_iv.is_empty()) {
+			iv.resize(16);
+			if (unlikely(!_fae_static_rng)) {
+				_fae_static_rng = memnew(CryptoCore::RandomGenerator);
+				if (_fae_static_rng->init() != OK) {
+					memdelete(_fae_static_rng);
+					_fae_static_rng = nullptr;
+					ERR_FAIL_V_MSG(FAILED, "Failed to initialize random number generator.");
+				}
+			}
+			Error err = _fae_static_rng->get_random_bytes(iv.ptrw(), 16);
+			ERR_FAIL_COND_V(err != OK, err);
+		} else {
+			ERR_FAIL_COND_V(p_iv.size() != 16, ERR_INVALID_PARAMETER);
+			iv = p_iv;
+		}
+
+	} else if (p_mode == MODE_READ) {
+		writing = false;
+		key = p_key;
+
+		if (use_magic) {
+			uint32_t magic = p_base->get_32();
+			ERR_FAIL_COND_V(magic != ENCRYPTED_HEADER_MAGIC, ERR_FILE_UNRECOGNIZED);
+		}
+
+		unsigned char md5d[16];
+		p_base->get_buffer(md5d, 16);
+		length = p_base->get_64();
+
+		iv.resize(16);
+		p_base->get_buffer(iv.ptrw(), 16);
+
+		base = p_base->get_position();
+		ERR_FAIL_COND_V(p_base->get_length() < base + length, ERR_FILE_CORRUPT);
+		uint64_t ds = length;
+		if (ds % 16) {
+			ds += 16 - (ds % 16);
+		}
+		data.resize(ds);
+
+		uint64_t blen = p_base->get_buffer(data.ptrw(), ds);
+		ERR_FAIL_COND_V(blen != ds, ERR_FILE_CORRUPT);
+
+		{
+			CryptoCore::AESContext ctx;
+
+			ctx.set_encode_key(key.ptrw(), 256); // Due to the nature of CFB, same key schedule is used for both encryption and decryption!
+			ctx.decrypt_cfb(ds, iv.ptrw(), data.ptrw(), data.ptrw());
+		}
+
+		data.resize(length);
+
+		unsigned char hash[16];
+		ERR_FAIL_COND_V(CryptoCore::md5(data.ptr(), data.size(), hash) != OK, ERR_BUG);
+
+		ERR_FAIL_COND_V_MSG(String::md5(hash) != String::md5(md5d), ERR_FILE_CORRUPT, "The MD5 sum of the decrypted file does not match the expected value. It could be that the file is corrupt, or that the provided decryption key is invalid.");
+
+		file = p_base;
+	}
+
+	return OK;
+}
+
+Error FileAccessEncrypted::open_and_parse_password(Ref<FileAccess> p_base, const String &p_key, Mode p_mode) {
+	String cs = p_key.md5_text();
+	ERR_FAIL_COND_V(cs.length() != 32, ERR_INVALID_PARAMETER);
+	Vector<uint8_t> key_md5;
+	key_md5.resize(32);
+	for (int i = 0; i < 32; i++) {
+		key_md5.write[i] = cs[i];
+	}
+
+	return open_and_parse(p_base, key_md5, p_mode);
+}
+
+Error FileAccessEncrypted::open_internal(const String &p_path, int p_mode_flags) {
+	return OK;
+}
+
+void FileAccessEncrypted::_close() {
+	if (file.is_null()) {
+		return;
+	}
+
+	if (writing) {
+		Vector<uint8_t> compressed;
+		uint64_t len = data.size();
+		if (len % 16) {
+			len += 16 - (len % 16);
+		}
+
+		unsigned char hash[16];
+		ERR_FAIL_COND(CryptoCore::md5(data.ptr(), data.size(), hash) != OK); // Bug?
+
+		compressed.resize(len);
+		memset(compressed.ptrw(), 0, len);
+		for (int i = 0; i < data.size(); i++) {
+			compressed.write[i] = data[i];
+		}
+
+		CryptoCore::AESContext ctx;
+		ctx.set_encode_key(key.ptrw(), 256);
+
+		if (use_magic) {
+			file->store_32(ENCRYPTED_HEADER_MAGIC);
+		}
+
+		file->store_buffer(hash, 16);
+		file->store_64(data.size());
+		file->store_buffer(iv.ptr(), 16);
+
+		ctx.encrypt_cfb(len, iv.ptrw(), compressed.ptrw(), compressed.ptrw());
+
+		file->store_buffer(compressed.ptr(), compressed.size());
+		data.clear();
+	}
+
+	file.unref();
+}
+
+bool FileAccessEncrypted::is_open() const {
+	return file.is_valid();
+}
+
+String FileAccessEncrypted::get_path() const {
+	if (file.is_valid()) {
+		return file->get_path();
+	} else {
+		return "";
+	}
+}
+
+String FileAccessEncrypted::get_path_absolute() const {
+	if (file.is_valid()) {
+		return file->get_path_absolute();
+	} else {
+		return "";
+	}
+}
+
+void FileAccessEncrypted::seek(uint64_t p_position) {
+	if (p_position > get_length()) {
+		p_position = get_length();
+	}
+
+	pos = p_position;
+	eofed = false;
+}
+
+void FileAccessEncrypted::seek_end(int64_t p_position) {
+	seek(get_length() + p_position);
+}
+
+uint64_t FileAccessEncrypted::get_position() const {
+	return pos;
+}
+
+uint64_t FileAccessEncrypted::get_length() const {
+	return data.size();
+}
+
+bool FileAccessEncrypted::eof_reached() const {
+	return eofed;
+}
+
+uint64_t FileAccessEncrypted::get_buffer(uint8_t *p_dst, uint64_t p_length) const {
+	ERR_FAIL_COND_V_MSG(writing, -1, "File has not been opened in read mode.");
+
+	if (!p_length) {
+		return 0;
+	}
+
+	ERR_FAIL_NULL_V(p_dst, -1);
+
+	uint64_t to_copy = MIN(p_length, get_length() - pos);
+
+	memcpy(p_dst, data.ptr() + pos, to_copy);
+	pos += to_copy;
+
+	if (to_copy < p_length) {
+		eofed = true;
+	}
+
+	return to_copy;
+}
+
+Error FileAccessEncrypted::get_error() const {
+	return eofed ? ERR_FILE_EOF : OK;
+}
+
+bool FileAccessEncrypted::store_buffer(const uint8_t *p_src, uint64_t p_length) {
+	ERR_FAIL_COND_V_MSG(!writing, false, "File has not been opened in write mode.");
+
+	if (!p_length) {
+		return true;
+	}
+
+	ERR_FAIL_NULL_V(p_src, false);
+
+	if (pos + p_length >= get_length()) {
+		ERR_FAIL_COND_V(data.resize(pos + p_length) != OK, false);
+	}
+
+	memcpy(data.ptrw() + pos, p_src, p_length);
+	pos += p_length;
+
+	return true;
+}
+
+void FileAccessEncrypted::flush() {
+	ERR_FAIL_COND_MSG(!writing, "File has not been opened in write mode.");
+
+	// encrypted files keep data in memory till close()
+}
+
+bool FileAccessEncrypted::file_exists(const String &p_name) {
+	Ref<FileAccess> fa = FileAccess::open(p_name, FileAccess::READ);
+	if (fa.is_null()) {
+		return false;
+	}
+	return true;
+}
+
+uint64_t FileAccessEncrypted::_get_modified_time(const String &p_file) {
+	if (file.is_valid()) {
+		return file->get_modified_time(p_file);
+	} else {
+		return 0;
+	}
+}
+
+uint64_t FileAccessEncrypted::_get_access_time(const String &p_file) {
+	if (file.is_valid()) {
+		return file->get_access_time(p_file);
+	} else {
+		return 0;
+	}
+}
+
+int64_t FileAccessEncrypted::_get_size(const String &p_file) {
+	if (file.is_valid()) {
+		return file->get_size(p_file);
+	} else {
+		return -1;
+	}
+}
+
+BitField<FileAccess::UnixPermissionFlags> FileAccessEncrypted::_get_unix_permissions(const String &p_file) {
+	if (file.is_valid()) {
+		return file->_get_unix_permissions(p_file);
+	}
+	return 0;
+}
+
+Error FileAccessEncrypted::_set_unix_permissions(const String &p_file, BitField<FileAccess::UnixPermissionFlags> p_permissions) {
+	if (file.is_valid()) {
+		return file->_set_unix_permissions(p_file, p_permissions);
+	}
+	return FAILED;
+}
+
+bool FileAccessEncrypted::_get_hidden_attribute(const String &p_file) {
+	if (file.is_valid()) {
+		return file->_get_hidden_attribute(p_file);
+	}
+	return false;
+}
+
+Error FileAccessEncrypted::_set_hidden_attribute(const String &p_file, bool p_hidden) {
+	if (file.is_valid()) {
+		return file->_set_hidden_attribute(p_file, p_hidden);
+	}
+	return FAILED;
+}
+
+bool FileAccessEncrypted::_get_read_only_attribute(const String &p_file) {
+	if (file.is_valid()) {
+		return file->_get_read_only_attribute(p_file);
+	}
+	return false;
+}
+
+Error FileAccessEncrypted::_set_read_only_attribute(const String &p_file, bool p_ro) {
+	if (file.is_valid()) {
+		return file->_set_read_only_attribute(p_file, p_ro);
+	}
+	return FAILED;
+}
+
+void FileAccessEncrypted::close() {
+	_close();
+}
+
+FileAccessEncrypted::~FileAccessEncrypted() {
+	_close();
+}