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Location: cpp/openttd-patchpack/source/src/signature.cpp
r28645:c09eac136c46
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text/x-c
Change: Link houses production on industry chain graph by TPE_PASSENGERS or TPE_MAIL cargo.
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* This file is part of OpenTTD.
* OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
* OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
*/
/** @file signature.cpp Implementation of signature validation routines. */
#include "stdafx.h"
#include "signature.h"
#include "debug.h"
#include "fileio_func.h"
#include "string_func.h"
#include "3rdparty/monocypher/monocypher.h"
#include "3rdparty/monocypher/monocypher-ed25519.h"
#include "3rdparty/nlohmann/json.hpp"
#include "safeguards.h"
/** The public keys used for signature validation. */
static const std::initializer_list<std::array<uint8_t, 32>> _public_keys_v1 = {
/* 2024-01-20 - Public key for Social Integration Plugins. */
{ 0xed, 0x5d, 0x57, 0x47, 0x21, 0x99, 0x8b, 0x02, 0xdf, 0x6e, 0x3d, 0x69, 0xe1, 0x87, 0xca, 0xd0, 0x0e, 0x88, 0xc3, 0xe2, 0xb2, 0xa6, 0x7b, 0xc0, 0x42, 0xc8, 0xd6, 0x4b, 0x65, 0xe6, 0x48, 0xf7 },
};
/**
* Calculate the 32-byte blake2b hash of a file.
*
* @param filename The filename to calculate the hash of.
* @return The 32-byte blake2b hash of the file, hex-encoded.
*/
static std::string CalculateHashV1(const std::string &filename)
{
FILE *f = FioFOpenFile(filename, "rb", NO_DIRECTORY);
if (f == nullptr) {
return "";
}
std::array<uint8_t, 32> digest;
crypto_blake2b_ctx ctx;
crypto_blake2b_init(&ctx, digest.size());
while (!feof(f)) {
std::array<uint8_t, 1024> buf;
size_t len = fread(buf.data(), 1, buf.size(), f);
crypto_blake2b_update(&ctx, buf.data(), len);
}
fclose(f);
crypto_blake2b_final(&ctx, digest.data());
return FormatArrayAsHex(digest);
}
/**
* Validate whether the checksum of a file is the same.
*
* @param filename The filename to validate the checksum of.
* @param checksum The expected checksum.
* @return True iff the checksum of the file is the same as the expected checksum.
*/
static bool ValidateChecksum(const std::string &filename, const std::string &checksum)
{
/* Checksums are "<version>$<hash>". Split out the version. */
auto pos = checksum.find('$');
assert(pos != std::string::npos); // Already validated by ValidateSchema().
const std::string version = checksum.substr(0, pos);
const std::string hash = checksum.substr(pos + 1);
/* Calculate the checksum over the file. */
std::string calculated_hash;
if (version == "1") {
calculated_hash = CalculateHashV1(filename);
} else {
Debug(misc, 0, "Failed to validate signature: unknown checksum version: {}", filename);
return false;
}
/* Validate the checksum is the same. */
if (calculated_hash.empty()) {
Debug(misc, 0, "Failed to validate signature: couldn't calculate checksum for: {}", filename);
return false;
}
if (calculated_hash != hash) {
Debug(misc, 0, "Failed to validate signature: checksum mismatch for: {}", filename);
return false;
}
return true;
}
/**
* Validate whether the signature is valid for this set of files.
*
* @param signature The signature to validate.
* @param files The files to validate the signature against.
* @param filename The filename of the signatures file (for error-reporting).
* @return True iff the signature is valid for this set of files.
*/
static bool ValidateSignature(const std::string &signature, const nlohmann::json &files, const std::string &filename)
{
/* Signatures are "<version>$<signature>". Split out the version. */
auto pos = signature.find('$');
assert(pos != std::string::npos); // Already validated by ValidateSchema().
const std::string version = signature.substr(0, pos);
const std::string sig_value = signature.substr(pos + 1);
/* Create the message we are going to validate. */
std::string message = files.dump(-1);
/* Validate the signature. */
if (version == "1") {
std::array<uint8_t, 64> sig;
if (sig_value.size() != 128 || !ConvertHexToBytes(sig_value, sig)) {
Debug(misc, 0, "Failed to validate signature: invalid signature: {}", filename);
return false;
}
for (auto &pk_value : _public_keys_v1) {
/* Check if the message is valid with this public key. */
auto res = crypto_ed25519_check(sig.data(), pk_value.data(), reinterpret_cast<uint8_t *>(message.data()), message.size());
if (res == 0) {
return true;
}
}
Debug(misc, 0, "Failed to validate signature: signature validation failed: {}", filename);
return false;
} else {
Debug(misc, 0, "Failed to validate signature: unknown signature version: {}", filename);
return false;
}
return true;
}
/**
* Validate the signatures file complies with the JSON schema.
*
* @param signatures The signatures JSON to validate.
* @param filename The filename of the signatures file (for error-reporting).
* @return True iff the signatures file complies with the JSON schema.
*/
static bool ValidateSchema(const nlohmann::json &signatures, const std::string &filename)
{
if (signatures["files"].is_null()) {
Debug(misc, 0, "Failed to validate signature: no files found: {}", filename);
return false;
}
if (signatures["signature"].is_null()) {
Debug(misc, 0, "Failed to validate signature: no signature found: {}", filename);
return false;
}
for (auto &signature : signatures["files"]) {
if (signature["filename"].is_null() || signature["checksum"].is_null()) {
Debug(misc, 0, "Failed to validate signature: invalid entry in files: {}", filename);
return false;
}
const std::string sig_filename = signature["filename"];
const std::string sig_checksum = signature["checksum"];
if (sig_filename.empty() || sig_checksum.empty()) {
Debug(misc, 0, "Failed to validate signature: invalid entry in files: {}", filename);
return false;
}
auto pos = sig_checksum.find('$');
if (pos == std::string::npos) {
Debug(misc, 0, "Failed to validate signature: invalid checksum format: {}", filename);
return false;
}
}
const std::string signature = signatures["signature"];
auto pos = signature.find('$');
if (pos == std::string::npos) {
Debug(misc, 0, "Failed to validate signature: invalid signature format: {}", filename);
return false;
}
return true;
}
/**
* Validate that the signatures mentioned in the signature file are matching
* the files in question.
*
* @return True iff the files in the signature file passed validation.
*/
static bool _ValidateSignatureFile(const std::string &filename)
{
size_t filesize;
FILE *f = FioFOpenFile(filename, "rb", NO_DIRECTORY, &filesize);
if (f == nullptr) {
Debug(misc, 0, "Failed to validate signature: file not found: {}", filename);
return false;
}
std::string text(filesize, '\0');
size_t len = fread(text.data(), filesize, 1, f);
if (len != 1) {
Debug(misc, 0, "Failed to validate signature: failed to read file: {}", filename);
return false;
}
nlohmann::json signatures;
try {
signatures = nlohmann::json::parse(text);
} catch (nlohmann::json::exception &) {
Debug(misc, 0, "Failed to validate signature: not a valid JSON file: {}", filename);
return false;
}
/*
* The JSON file should look like:
*
* {
* "files": [
* {
* "checksum": "version$hash"
* "filename": "filename",
* },
* ...
* ],
* "signature": "version$signature"
* }
*
* The signature is a signed message of the content of "files", dumped as
* JSON without spaces / newlines, keys in the order as indicated above.
*/
if (!ValidateSchema(signatures, filename)) {
return false;
}
if (!ValidateSignature(signatures["signature"], signatures["files"], filename)) {
return false;
}
std::string dirname = std::filesystem::path(filename).parent_path().string();
for (auto &signature : signatures["files"]) {
const std::string sig_filename = dirname + PATHSEPCHAR + signature["filename"].get<std::string>();
const std::string sig_checksum = signature["checksum"];
if (!ValidateChecksum(sig_filename, sig_checksum)) {
return false;
}
}
return true;
}
/**
* Validate that the signatures mentioned in the signature file are matching
* the files in question.
*
* @note if ALLOW_INVALID_SIGNATURE is defined, this function will always
* return true (but will still report any errors in the console).
*
* @return True iff the files in the signature file passed validation.
*/
bool ValidateSignatureFile(const std::string &filename)
{
auto res = _ValidateSignatureFile(filename);;
#if defined(ALLOW_INVALID_SIGNATURE)
(void)res; // Ignore the result.
return true;
#else
return res;
#endif
}
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