godot/core/io/pck_packer.cpp
David Nikdel 067807c1cb Remove nondeterminism in pck_packer
PCK files (like other build products) should be deterministic based on their inputs. Removed calls to Math::rand() that are being used to generate padding.

Looks like these were introduced as part of adding encryption support, but the padding being random does not have any cryptographic significance. This can be trivially inferred since file blocks that happen to be aligned don't get padding anyway.

If there's a desire to indroduce something that functions as a nonce it should probably be added explicitly and only if encryption is enabled.
remove Math::rand() calls in editor_export_platform.cpp

follow up to make consistent with pck_packer
2023-09-03 18:14:30 -04:00

262 lines
8.3 KiB
C++

/**************************************************************************/
/* pck_packer.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 "pck_packer.h"
#include "core/crypto/crypto_core.h"
#include "core/io/file_access.h"
#include "core/io/file_access_encrypted.h"
#include "core/io/file_access_pack.h" // PACK_HEADER_MAGIC, PACK_FORMAT_VERSION
#include "core/version.h"
static int _get_pad(int p_alignment, int p_n) {
int rest = p_n % p_alignment;
int pad = 0;
if (rest > 0) {
pad = p_alignment - rest;
}
return pad;
}
void PCKPacker::_bind_methods() {
ClassDB::bind_method(D_METHOD("pck_start", "pck_name", "alignment", "key", "encrypt_directory"), &PCKPacker::pck_start, DEFVAL(32), DEFVAL("0000000000000000000000000000000000000000000000000000000000000000"), DEFVAL(false));
ClassDB::bind_method(D_METHOD("add_file", "pck_path", "source_path", "encrypt"), &PCKPacker::add_file, DEFVAL(false));
ClassDB::bind_method(D_METHOD("flush", "verbose"), &PCKPacker::flush, DEFVAL(false));
}
Error PCKPacker::pck_start(const String &p_file, int p_alignment, const String &p_key, bool p_encrypt_directory) {
ERR_FAIL_COND_V_MSG((p_key.is_empty() || !p_key.is_valid_hex_number(false) || p_key.length() != 64), ERR_CANT_CREATE, "Invalid Encryption Key (must be 64 characters long).");
ERR_FAIL_COND_V_MSG(p_alignment <= 0, ERR_CANT_CREATE, "Invalid alignment, must be greater then 0.");
String _key = p_key.to_lower();
key.resize(32);
for (int i = 0; i < 32; i++) {
int v = 0;
if (i * 2 < _key.length()) {
char32_t ct = _key[i * 2];
if (is_digit(ct)) {
ct = ct - '0';
} else if (ct >= 'a' && ct <= 'f') {
ct = 10 + ct - 'a';
}
v |= ct << 4;
}
if (i * 2 + 1 < _key.length()) {
char32_t ct = _key[i * 2 + 1];
if (is_digit(ct)) {
ct = ct - '0';
} else if (ct >= 'a' && ct <= 'f') {
ct = 10 + ct - 'a';
}
v |= ct;
}
key.write[i] = v;
}
enc_dir = p_encrypt_directory;
file = FileAccess::open(p_file, FileAccess::WRITE);
ERR_FAIL_COND_V_MSG(file.is_null(), ERR_CANT_CREATE, "Can't open file to write: " + String(p_file) + ".");
alignment = p_alignment;
file->store_32(PACK_HEADER_MAGIC);
file->store_32(PACK_FORMAT_VERSION);
file->store_32(VERSION_MAJOR);
file->store_32(VERSION_MINOR);
file->store_32(VERSION_PATCH);
uint32_t pack_flags = 0;
if (enc_dir) {
pack_flags |= PACK_DIR_ENCRYPTED;
}
file->store_32(pack_flags); // flags
files.clear();
ofs = 0;
return OK;
}
Error PCKPacker::add_file(const String &p_file, const String &p_src, bool p_encrypt) {
ERR_FAIL_COND_V_MSG(file.is_null(), ERR_INVALID_PARAMETER, "File must be opened before use.");
Ref<FileAccess> f = FileAccess::open(p_src, FileAccess::READ);
if (f.is_null()) {
return ERR_FILE_CANT_OPEN;
}
File pf;
// Simplify path here and on every 'files' access so that paths that have extra '/'
// symbols in them still match to the MD5 hash for the saved path.
pf.path = p_file.simplify_path();
pf.src_path = p_src;
pf.ofs = ofs;
pf.size = f->get_length();
Vector<uint8_t> data = FileAccess::get_file_as_bytes(p_src);
{
unsigned char hash[16];
CryptoCore::md5(data.ptr(), data.size(), hash);
pf.md5.resize(16);
for (int i = 0; i < 16; i++) {
pf.md5.write[i] = hash[i];
}
}
pf.encrypted = p_encrypt;
uint64_t _size = pf.size;
if (p_encrypt) { // Add encryption overhead.
if (_size % 16) { // Pad to encryption block size.
_size += 16 - (_size % 16);
}
_size += 16; // hash
_size += 8; // data size
_size += 16; // iv
}
int pad = _get_pad(alignment, ofs + _size);
ofs = ofs + _size + pad;
files.push_back(pf);
return OK;
}
Error PCKPacker::flush(bool p_verbose) {
ERR_FAIL_COND_V_MSG(file.is_null(), ERR_INVALID_PARAMETER, "File must be opened before use.");
int64_t file_base_ofs = file->get_position();
file->store_64(0); // files base
for (int i = 0; i < 16; i++) {
file->store_32(0); // reserved
}
// write the index
file->store_32(files.size());
Ref<FileAccessEncrypted> fae;
Ref<FileAccess> fhead = file;
if (enc_dir) {
fae.instantiate();
ERR_FAIL_COND_V(fae.is_null(), ERR_CANT_CREATE);
Error err = fae->open_and_parse(file, key, FileAccessEncrypted::MODE_WRITE_AES256, false);
ERR_FAIL_COND_V(err != OK, ERR_CANT_CREATE);
fhead = fae;
}
for (int i = 0; i < files.size(); i++) {
int string_len = files[i].path.utf8().length();
int pad = _get_pad(4, string_len);
fhead->store_32(string_len + pad);
fhead->store_buffer((const uint8_t *)files[i].path.utf8().get_data(), string_len);
for (int j = 0; j < pad; j++) {
fhead->store_8(0);
}
fhead->store_64(files[i].ofs);
fhead->store_64(files[i].size); // pay attention here, this is where file is
fhead->store_buffer(files[i].md5.ptr(), 16); //also save md5 for file
uint32_t flags = 0;
if (files[i].encrypted) {
flags |= PACK_FILE_ENCRYPTED;
}
fhead->store_32(flags);
}
if (fae.is_valid()) {
fhead.unref();
fae.unref();
}
int header_padding = _get_pad(alignment, file->get_position());
for (int i = 0; i < header_padding; i++) {
file->store_8(0);
}
int64_t file_base = file->get_position();
file->seek(file_base_ofs);
file->store_64(file_base); // update files base
file->seek(file_base);
const uint32_t buf_max = 65536;
uint8_t *buf = memnew_arr(uint8_t, buf_max);
int count = 0;
for (int i = 0; i < files.size(); i++) {
Ref<FileAccess> src = FileAccess::open(files[i].src_path, FileAccess::READ);
uint64_t to_write = files[i].size;
Ref<FileAccess> ftmp = file;
if (files[i].encrypted) {
fae.instantiate();
ERR_FAIL_COND_V(fae.is_null(), ERR_CANT_CREATE);
Error err = fae->open_and_parse(file, key, FileAccessEncrypted::MODE_WRITE_AES256, false);
ERR_FAIL_COND_V(err != OK, ERR_CANT_CREATE);
ftmp = fae;
}
while (to_write > 0) {
uint64_t read = src->get_buffer(buf, MIN(to_write, buf_max));
ftmp->store_buffer(buf, read);
to_write -= read;
}
if (fae.is_valid()) {
ftmp.unref();
fae.unref();
}
int pad = _get_pad(alignment, file->get_position());
for (int j = 0; j < pad; j++) {
file->store_8(0);
}
count += 1;
const int file_num = files.size();
if (p_verbose && (file_num > 0)) {
print_line(vformat("[%d/%d - %d%%] PCKPacker flush: %s -> %s", count, file_num, float(count) / file_num * 100, files[i].src_path, files[i].path));
}
}
file.unref();
memdelete_arr(buf);
return OK;
}