From 83e5b3b0eba7ef437e0e1f8d3c73fc7cec2a19ef Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Lukas=20Br=C3=BCbach?= Date: Tue, 4 Aug 2026 10:02:35 +0200 Subject: [PATCH] [Security] Use a CSPRNG for salts, tokens, and RNG seeding Password salts and activation tokens were generated with the global SFMT RNG, which was seeded from a 32-bit timestamp, making registration salts and activation tokens predictable. The game RNG used the same timestamp seed across restarts. Add CryptoUtil backed by OpenSSL RAND_bytes and use it for salt/token generation and to seed RNG_SFMT with a 64-bit CSPRNG value in both the client and server. Link libcockatrice_utility against OpenSSL::Crypto. --- cockatrice/src/main.cpp | 3 +- .../libcockatrice/rng/rng_sfmt.cpp | 7 ++++ .../libcockatrice/rng/rng_sfmt.h | 1 + libcockatrice_utility/CMakeLists.txt | 9 ++-- .../libcockatrice/utility/cryptoutil.cpp | 25 +++++++++++ .../libcockatrice/utility/cryptoutil.h | 13 ++++++ .../libcockatrice/utility/passwordhasher.cpp | 26 +++++++++--- servatrice/src/main.cpp | 3 +- tests/password_hash_test.cpp | 41 +++++++++++-------- 9 files changed, 101 insertions(+), 27 deletions(-) create mode 100644 libcockatrice_utility/libcockatrice/utility/cryptoutil.cpp create mode 100644 libcockatrice_utility/libcockatrice/utility/cryptoutil.h diff --git a/cockatrice/src/main.cpp b/cockatrice/src/main.cpp index dbfd2b6b7..062fda142 100644 --- a/cockatrice/src/main.cpp +++ b/cockatrice/src/main.cpp @@ -44,6 +44,7 @@ #include #include #include +#include QTranslator *translator, *qtTranslator; RNG_Abstract *rng; @@ -241,7 +242,7 @@ int main(int argc, char *argv[]) Logger::getInstance().logToFile(true); } - rng = new RNG_SFMT; + rng = new RNG_SFMT(CryptoUtil::randomUInt64()); themeManager = new ThemeManager; soundEngine = new SoundEngine; diff --git a/libcockatrice_rng/libcockatrice/rng/rng_sfmt.cpp b/libcockatrice_rng/libcockatrice/rng/rng_sfmt.cpp index 5b38deb3f..17cc77a22 100644 --- a/libcockatrice_rng/libcockatrice/rng/rng_sfmt.cpp +++ b/libcockatrice_rng/libcockatrice/rng/rng_sfmt.cpp @@ -17,6 +17,13 @@ RNG_SFMT::RNG_SFMT(QObject *parent) : RNG_Abstract(parent) sfmt_init_gen_rand(&sfmt, QDateTime::currentDateTime().toSecsSinceEpoch()); } +RNG_SFMT::RNG_SFMT(uint64_t seed, QObject *parent) : RNG_Abstract(parent) +{ + // initialize the random number generator with a 64bit seed, e.g. from a CSPRNG + uint32_t seedArray[2] = {static_cast(seed), static_cast(seed >> 32)}; + sfmt_init_by_array(&sfmt, seedArray, 2); +} + /** * This method is the rand() equivalent which calls the cdf with proper bounds. * diff --git a/libcockatrice_rng/libcockatrice/rng/rng_sfmt.h b/libcockatrice_rng/libcockatrice/rng/rng_sfmt.h index 7e9f53df3..b12401799 100644 --- a/libcockatrice_rng/libcockatrice/rng/rng_sfmt.h +++ b/libcockatrice_rng/libcockatrice/rng/rng_sfmt.h @@ -37,6 +37,7 @@ private: public: explicit RNG_SFMT(QObject *parent = nullptr); + explicit RNG_SFMT(uint64_t seed, QObject *parent = nullptr); unsigned int rand(int min, int max) override; }; diff --git a/libcockatrice_utility/CMakeLists.txt b/libcockatrice_utility/CMakeLists.txt index 2d34cad31..594749623 100644 --- a/libcockatrice_utility/CMakeLists.txt +++ b/libcockatrice_utility/CMakeLists.txt @@ -5,12 +5,13 @@ set(CMAKE_AUTOMOC ON) set(CMAKE_AUTOUIC ON) set(CMAKE_AUTORCC ON) -set(UTILITY_SOURCES libcockatrice/utility/expression.cpp libcockatrice/utility/levenshtein.cpp - libcockatrice/utility/passwordhasher.cpp +set(UTILITY_SOURCES libcockatrice/utility/cryptoutil.cpp libcockatrice/utility/expression.cpp + libcockatrice/utility/levenshtein.cpp libcockatrice/utility/passwordhasher.cpp ) set(UTILITY_HEADERS libcockatrice/utility/color.h + libcockatrice/utility/cryptoutil.h libcockatrice/utility/expression.h libcockatrice/utility/levenshtein.h libcockatrice/utility/macros.h @@ -27,7 +28,9 @@ add_library(libcockatrice_utility STATIC ${UTILITY_SOURCES} ${UTILITY_HEADERS}) target_include_directories(libcockatrice_utility PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}) -target_link_libraries(libcockatrice_utility PUBLIC libcockatrice_rng ${QT_CORE_MODULE}) +find_package(OpenSSL REQUIRED) + +target_link_libraries(libcockatrice_utility PUBLIC libcockatrice_rng OpenSSL::Crypto ${QT_CORE_MODULE}) set(ORACLE_LIBS) diff --git a/libcockatrice_utility/libcockatrice/utility/cryptoutil.cpp b/libcockatrice_utility/libcockatrice/utility/cryptoutil.cpp new file mode 100644 index 000000000..416ef261b --- /dev/null +++ b/libcockatrice_utility/libcockatrice/utility/cryptoutil.cpp @@ -0,0 +1,25 @@ +#include "cryptoutil.h" + +#include + +namespace CryptoUtil +{ +QByteArray randomBytes(int count) +{ + QByteArray bytes(count, '\0'); + if (RAND_bytes(reinterpret_cast(bytes.data()), count) != 1) { + // Randomness failure is fatal: never fall back to a predictable source. + qFatal("CryptoUtil::randomBytes: RAND_bytes failed"); + } + return bytes; +} + +quint64 randomUInt64() +{ + quint64 value; + if (RAND_bytes(reinterpret_cast(&value), sizeof(value)) != 1) { + qFatal("CryptoUtil::randomUInt64: RAND_bytes failed"); + } + return value; +} +} // namespace CryptoUtil diff --git a/libcockatrice_utility/libcockatrice/utility/cryptoutil.h b/libcockatrice_utility/libcockatrice/utility/cryptoutil.h new file mode 100644 index 000000000..dba9dc37d --- /dev/null +++ b/libcockatrice_utility/libcockatrice/utility/cryptoutil.h @@ -0,0 +1,13 @@ +#ifndef CRYPTOUTIL_H +#define CRYPTOUTIL_H + +#include +#include + +namespace CryptoUtil +{ +QByteArray randomBytes(int count); +quint64 randomUInt64(); +} // namespace CryptoUtil + +#endif diff --git a/libcockatrice_utility/libcockatrice/utility/passwordhasher.cpp b/libcockatrice_utility/libcockatrice/utility/passwordhasher.cpp index c40c5f94f..1c22fdcfa 100644 --- a/libcockatrice_utility/libcockatrice/utility/passwordhasher.cpp +++ b/libcockatrice_utility/libcockatrice/utility/passwordhasher.cpp @@ -1,7 +1,7 @@ #include "passwordhasher.h" #include -#include +#include QString PasswordHasher::computeHash(const QString &password, const QString &salt) { @@ -21,12 +21,28 @@ QString PasswordHasher::generateRandomSalt(const int len) static const char alphanum[] = "0123456789" "ABCDEFGHIJKLMNOPQRSTUVWXYZ" "abcdefghijklmnopqrstuvwxyz"; + const int size = sizeof(alphanum) - 1; + + // Two bytes per character, corrected for modulo bias via rejection sampling. + const int bucketSize = 65536 / size; + const int limit = bucketSize * size; QString ret; - int size = sizeof(alphanum) - 1; - + ret.reserve(len); + QByteArray random = CryptoUtil::randomBytes(len * 2); + int bytesUsed = 0; for (int i = 0; i < len; ++i) { - ret.append(alphanum[rng->rand(0, size)]); + unsigned int value; + do { + if (bytesUsed >= random.size()) { + random = CryptoUtil::randomBytes(len * 2); + bytesUsed = 0; + } + value = static_cast(static_cast(random.at(bytesUsed))) << 8 | + static_cast(static_cast(random.at(bytesUsed + 1))); + bytesUsed += 2; + } while (value >= limit); + ret.append(alphanum[value / bucketSize]); } return ret; @@ -34,5 +50,5 @@ QString PasswordHasher::generateRandomSalt(const int len) QString PasswordHasher::generateActivationToken() { - return QCryptographicHash::hash(generateRandomSalt().toUtf8(), QCryptographicHash::Md5).toBase64().left(16); + return QString(CryptoUtil::randomBytes(16).toBase64().left(16)); } diff --git a/servatrice/src/main.cpp b/servatrice/src/main.cpp index 9e7fe38d9..13bf95a82 100644 --- a/servatrice/src/main.cpp +++ b/servatrice/src/main.cpp @@ -33,6 +33,7 @@ #include #include #include +#include #include RNG_Abstract *rng; @@ -169,7 +170,7 @@ int main(int argc, char *argv[]) signalhandler = new SignalHandler(); - rng = new RNG_SFMT; + rng = new RNG_SFMT(CryptoUtil::randomUInt64()); std::cerr << "Servatrice " << VERSION_STRING << " starting." << std::endl; std::cerr << "-------------------------" << std::endl; diff --git a/tests/password_hash_test.cpp b/tests/password_hash_test.cpp index 38d9b6315..2b8f8bdb7 100644 --- a/tests/password_hash_test.cpp +++ b/tests/password_hash_test.cpp @@ -1,25 +1,9 @@ #include "gtest/gtest.h" -#include -#include +#include #include -RNG_Abstract *rng; - namespace { -class PasswordHashTest : public ::testing::Test -{ -protected: - void SetUp() override - { - rng = new RNG_SFMT; - } - - void TearDown() override - { - delete rng; - } -}; TEST(PasswordHashTest, RegressionTest) { @@ -29,6 +13,29 @@ TEST(PasswordHashTest, RegressionTest) QString hash = PasswordHasher::computeHash(password, salt); ASSERT_EQ(hash, salt + expected) << "The computed hash value remains the same"; } + +TEST(PasswordHashTest, SaltUsesAlphanumericCharset) +{ + static const char alphanum[] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"; + const QString salt = PasswordHasher::generateRandomSalt(); + ASSERT_EQ(salt.size(), 16); + for (const QChar &c : salt) { + ASSERT_NE(strchr(alphanum, c.toLatin1()), nullptr); + } +} + +TEST(PasswordHashTest, SaltsAreUnique) +{ + const QString salt1 = PasswordHasher::generateRandomSalt(); + const QString salt2 = PasswordHasher::generateRandomSalt(); + ASSERT_NE(salt1, salt2); +} + +TEST(PasswordHashTest, TokenHasExpectedLength) +{ + const QString token = PasswordHasher::generateActivationToken(); + ASSERT_EQ(token.size(), 16); +} } // namespace int main(int argc, char **argv)