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-rw-r--r--core/crypto/SCsub15
-rw-r--r--core/crypto/crypto.cpp47
-rw-r--r--core/crypto/crypto.h23
3 files changed, 83 insertions, 2 deletions
diff --git a/core/crypto/SCsub b/core/crypto/SCsub
index da4a9c9381..4f3104d84b 100644
--- a/core/crypto/SCsub
+++ b/core/crypto/SCsub
@@ -6,6 +6,7 @@ env_crypto = env.Clone()
is_builtin = env["builtin_mbedtls"]
has_module = env["module_mbedtls_enabled"]
+thirdparty_obj = []
if is_builtin or not has_module:
# Use our headers for builtin or if the module is not going to be compiled.
@@ -35,6 +36,16 @@ if not has_module:
"godot_core_mbedtls_platform.c",
]
thirdparty_mbedtls_sources = [thirdparty_mbedtls_dir + file for file in thirdparty_mbedtls_sources]
- env_thirdparty.add_source_files(env.core_sources, thirdparty_mbedtls_sources)
+ env_thirdparty.add_source_files(thirdparty_obj, thirdparty_mbedtls_sources)
+ env.core_sources += thirdparty_obj
-env_crypto.add_source_files(env.core_sources, "*.cpp")
+
+# Godot source files
+
+core_obj = []
+
+env_crypto.add_source_files(core_obj, "*.cpp")
+env.core_sources += core_obj
+
+# Needed to force rebuilding the core files when the thirdparty library is updated.
+env.Depends(core_obj, thirdparty_obj)
diff --git a/core/crypto/crypto.cpp b/core/crypto/crypto.cpp
index d12108bca0..33ba0ba704 100644
--- a/core/crypto/crypto.cpp
+++ b/core/crypto/crypto.cpp
@@ -65,6 +65,22 @@ void X509Certificate::_bind_methods() {
ClassDB::bind_method(D_METHOD("load", "path"), &X509Certificate::load);
}
+/// HMACContext
+
+void HMACContext::_bind_methods() {
+ ClassDB::bind_method(D_METHOD("start", "hash_type", "key"), &HMACContext::start);
+ ClassDB::bind_method(D_METHOD("update", "data"), &HMACContext::update);
+ ClassDB::bind_method(D_METHOD("finish"), &HMACContext::finish);
+}
+
+HMACContext *(*HMACContext::_create)() = nullptr;
+HMACContext *HMACContext::create() {
+ if (_create) {
+ return _create();
+ }
+ ERR_FAIL_V_MSG(nullptr, "HMACContext is not available when the mbedtls module is disabled.");
+}
+
/// Crypto
void (*Crypto::_load_default_certificates)(String p_path) = nullptr;
@@ -82,6 +98,35 @@ void Crypto::load_default_certificates(String p_path) {
}
}
+PackedByteArray Crypto::hmac_digest(HashingContext::HashType p_hash_type, PackedByteArray p_key, PackedByteArray p_msg) {
+ Ref<HMACContext> ctx = Ref<HMACContext>(HMACContext::create());
+ ERR_FAIL_COND_V_MSG(ctx.is_null(), PackedByteArray(), "HMAC is not available witout mbedtls module.");
+ Error err = ctx->start(p_hash_type, p_key);
+ ERR_FAIL_COND_V(err != OK, PackedByteArray());
+ err = ctx->update(p_msg);
+ ERR_FAIL_COND_V(err != OK, PackedByteArray());
+ return ctx->finish();
+}
+
+// Compares two HMACS for equality without leaking timing information in order to prevent timing attakcs.
+// @see: https://paragonie.com/blog/2015/11/preventing-timing-attacks-on-string-comparison-with-double-hmac-strategy
+bool Crypto::constant_time_compare(PackedByteArray p_trusted, PackedByteArray p_received) {
+ const uint8_t *t = p_trusted.ptr();
+ const uint8_t *r = p_received.ptr();
+ int tlen = p_trusted.size();
+ int rlen = p_received.size();
+ // If the lengths are different then nothing else matters.
+ if (tlen != rlen) {
+ return false;
+ }
+
+ uint8_t v = 0;
+ for (int i = 0; i < tlen; i++) {
+ v |= t[i] ^ r[i];
+ }
+ return v == 0;
+}
+
void Crypto::_bind_methods() {
ClassDB::bind_method(D_METHOD("generate_random_bytes", "size"), &Crypto::generate_random_bytes);
ClassDB::bind_method(D_METHOD("generate_rsa", "size"), &Crypto::generate_rsa);
@@ -90,6 +135,8 @@ void Crypto::_bind_methods() {
ClassDB::bind_method(D_METHOD("verify", "hash_type", "hash", "signature", "key"), &Crypto::verify);
ClassDB::bind_method(D_METHOD("encrypt", "key", "plaintext"), &Crypto::encrypt);
ClassDB::bind_method(D_METHOD("decrypt", "key", "ciphertext"), &Crypto::decrypt);
+ ClassDB::bind_method(D_METHOD("hmac_digest", "hash_type", "key", "msg"), &Crypto::hmac_digest);
+ ClassDB::bind_method(D_METHOD("constant_time_compare", "trusted", "received"), &Crypto::constant_time_compare);
}
/// Resource loader/saver
diff --git a/core/crypto/crypto.h b/core/crypto/crypto.h
index 8325f043bf..5cacddaea0 100644
--- a/core/crypto/crypto.h
+++ b/core/crypto/crypto.h
@@ -67,6 +67,23 @@ public:
virtual Error save(String p_path) = 0;
};
+class HMACContext : public Reference {
+ GDCLASS(HMACContext, Reference);
+
+protected:
+ static void _bind_methods();
+ static HMACContext *(*_create)();
+
+public:
+ static HMACContext *create();
+
+ virtual Error start(HashingContext::HashType p_hash_type, PackedByteArray p_key) = 0;
+ virtual Error update(PackedByteArray p_data) = 0;
+ virtual PackedByteArray finish() = 0;
+
+ HMACContext() {}
+};
+
class Crypto : public Reference {
GDCLASS(Crypto, Reference);
@@ -88,6 +105,12 @@ public:
virtual Vector<uint8_t> encrypt(Ref<CryptoKey> p_key, Vector<uint8_t> p_plaintext) = 0;
virtual Vector<uint8_t> decrypt(Ref<CryptoKey> p_key, Vector<uint8_t> p_ciphertext) = 0;
+ PackedByteArray hmac_digest(HashingContext::HashType p_hash_type, PackedByteArray p_key, PackedByteArray p_msg);
+
+ // Compares two PackedByteArrays for equality without leaking timing information in order to prevent timing attacks.
+ // @see: https://paragonie.com/blog/2015/11/preventing-timing-attacks-on-string-comparison-with-double-hmac-strategy
+ bool constant_time_compare(PackedByteArray p_trusted, PackedByteArray p_received);
+
Crypto() {}
};