feat: HMAC support in Crypto APIs

6 files changed, 220 insertions, 4 deletions

diff --git a/modules/mbedtls/SCsub b/modules/mbedtls/SCsub
index 5f5d25a3ee..3b1739c6ee 100755
--- a/modules/mbedtls/SCsub
+++ b/modules/mbedtls/SCsub
@@ -100,3 +100,7 @@ if env["builtin_mbedtls"]:
 
 # Module sources
 env_mbed_tls.add_source_files(env.modules_sources, "*.cpp")
+
+if env["tests"]:
+    env_mbed_tls.Append(CPPDEFINES=["TESTS_ENABLED"])
+    env_mbed_tls.add_source_files(env.modules_sources, "./tests/*.cpp")
diff --git a/modules/mbedtls/crypto_mbedtls.cpp b/modules/mbedtls/crypto_mbedtls.cpp
index bec792450a..4ea38ebd60 100644
--- a/modules/mbedtls/crypto_mbedtls.cpp
+++ b/modules/mbedtls/crypto_mbedtls.cpp
@@ -44,6 +44,7 @@
 #define PEM_END_CRT "-----END CERTIFICATE-----\n"
 
 #include <mbedtls/debug.h>
+#include <mbedtls/md.h>
 #include <mbedtls/pem.h>
 
 CryptoKey *CryptoKeyMbedTLS::create() {
@@ -186,6 +187,68 @@ Error X509CertificateMbedTLS::save(String p_path) {
 	return OK;
 }
 
+bool HMACContextMbedTLS::is_md_type_allowed(mbedtls_md_type_t p_md_type) {
+	switch (p_md_type) {
+		case MBEDTLS_MD_SHA1:
+		case MBEDTLS_MD_SHA256:
+			return true;
+		default:
+			return false;
+	}
+}
+
+HMACContext *HMACContextMbedTLS::create() {
+	return memnew(HMACContextMbedTLS);
+}
+
+Error HMACContextMbedTLS::start(HashingContext::HashType p_hash_type, PackedByteArray p_key) {
+	ERR_FAIL_COND_V_MSG(ctx != nullptr, ERR_FILE_ALREADY_IN_USE, "HMACContext already started.");
+
+	// HMAC keys can be any size.
+	ERR_FAIL_COND_V_MSG(p_key.empty(), ERR_INVALID_PARAMETER, "Key must not be empty.");
+
+	hash_type = p_hash_type;
+	mbedtls_md_type_t ht = CryptoMbedTLS::md_type_from_hashtype(p_hash_type, hash_len);
+
+	bool allowed = HMACContextMbedTLS::is_md_type_allowed(ht);
+	ERR_FAIL_COND_V_MSG(!allowed, ERR_INVALID_PARAMETER, "Unsupported hash type.");
+
+	ctx = memalloc(sizeof(mbedtls_md_context_t));
+	mbedtls_md_init((mbedtls_md_context_t *)ctx);
+
+	mbedtls_md_setup((mbedtls_md_context_t *)ctx, mbedtls_md_info_from_type((mbedtls_md_type_t)ht), 1);
+	int ret = mbedtls_md_hmac_starts((mbedtls_md_context_t *)ctx, (const uint8_t *)p_key.ptr(), (size_t)p_key.size());
+	return ret ? FAILED : OK;
+}
+
+Error HMACContextMbedTLS::update(PackedByteArray p_data) {
+	ERR_FAIL_COND_V_MSG(ctx == nullptr, ERR_INVALID_DATA, "Start must be called before update.");
+
+	ERR_FAIL_COND_V_MSG(p_data.empty(), ERR_INVALID_PARAMETER, "Src must not be empty.");
+
+	int ret = mbedtls_md_hmac_update((mbedtls_md_context_t *)ctx, (const uint8_t *)p_data.ptr(), (size_t)p_data.size());
+	return ret ? FAILED : OK;
+}
+
+PackedByteArray HMACContextMbedTLS::finish() {
+	ERR_FAIL_COND_V_MSG(ctx == nullptr, PackedByteArray(), "Start must be called before finish.");
+	ERR_FAIL_COND_V_MSG(hash_len == 0, PackedByteArray(), "Unsupported hash type.");
+
+	PackedByteArray out;
+	out.resize(hash_len);
+
+	unsigned char *out_ptr = (unsigned char *)out.ptrw();
+	int ret = mbedtls_md_hmac_finish((mbedtls_md_context_t *)ctx, out_ptr);
+
+	mbedtls_md_free((mbedtls_md_context_t *)ctx);
+	memfree((mbedtls_md_context_t *)ctx);
+	ctx = nullptr;
+	hash_len = 0;
+
+	ERR_FAIL_COND_V_MSG(ret, PackedByteArray(), "Error received while finishing HMAC");
+	return out;
+}
+
 Crypto *CryptoMbedTLS::create() {
 	return memnew(CryptoMbedTLS);
 }
@@ -199,6 +262,7 @@ void CryptoMbedTLS::initialize_crypto() {
 	Crypto::_load_default_certificates = load_default_certificates;
 	X509CertificateMbedTLS::make_default();
 	CryptoKeyMbedTLS::make_default();
+	HMACContextMbedTLS::make_default();
 }
 
 void CryptoMbedTLS::finalize_crypto() {
@@ -210,6 +274,7 @@ void CryptoMbedTLS::finalize_crypto() {
 	}
 	X509CertificateMbedTLS::finalize();
 	CryptoKeyMbedTLS::finalize();
+	HMACContextMbedTLS::finalize();
 }
 
 CryptoMbedTLS::CryptoMbedTLS() {
@@ -313,7 +378,7 @@ PackedByteArray CryptoMbedTLS::generate_random_bytes(int p_bytes) {
 	return out;
 }
 
-mbedtls_md_type_t CryptoMbedTLS::_md_type_from_hashtype(HashingContext::HashType p_hash_type, int &r_size) {
+mbedtls_md_type_t CryptoMbedTLS::md_type_from_hashtype(HashingContext::HashType p_hash_type, int &r_size) {
 	switch (p_hash_type) {
 		case HashingContext::HASH_MD5:
 			r_size = 16;
@@ -332,7 +397,7 @@ mbedtls_md_type_t CryptoMbedTLS::_md_type_from_hashtype(HashingContext::HashType
 
 Vector<uint8_t> CryptoMbedTLS::sign(HashingContext::HashType p_hash_type, Vector<uint8_t> p_hash, Ref<CryptoKey> p_key) {
 	int size;
-	mbedtls_md_type_t type = _md_type_from_hashtype(p_hash_type, size);
+	mbedtls_md_type_t type = CryptoMbedTLS::md_type_from_hashtype(p_hash_type, size);
 	ERR_FAIL_COND_V_MSG(type == MBEDTLS_MD_NONE, Vector<uint8_t>(), "Invalid hash type.");
 	ERR_FAIL_COND_V_MSG(p_hash.size() != size, Vector<uint8_t>(), "Invalid hash provided. Size must be " + itos(size));
 	Ref<CryptoKeyMbedTLS> key = static_cast<Ref<CryptoKeyMbedTLS>>(p_key);
@@ -350,7 +415,7 @@ Vector<uint8_t> CryptoMbedTLS::sign(HashingContext::HashType p_hash_type, Vector
 
 bool CryptoMbedTLS::verify(HashingContext::HashType p_hash_type, Vector<uint8_t> p_hash, Vector<uint8_t> p_signature, Ref<CryptoKey> p_key) {
 	int size;
-	mbedtls_md_type_t type = _md_type_from_hashtype(p_hash_type, size);
+	mbedtls_md_type_t type = CryptoMbedTLS::md_type_from_hashtype(p_hash_type, size);
 	ERR_FAIL_COND_V_MSG(type == MBEDTLS_MD_NONE, false, "Invalid hash type.");
 	ERR_FAIL_COND_V_MSG(p_hash.size() != size, false, "Invalid hash provided. Size must be " + itos(size));
 	Ref<CryptoKeyMbedTLS> key = static_cast<Ref<CryptoKeyMbedTLS>>(p_key);
diff --git a/modules/mbedtls/crypto_mbedtls.h b/modules/mbedtls/crypto_mbedtls.h
index e40ca08643..990f8ae578 100644
--- a/modules/mbedtls/crypto_mbedtls.h
+++ b/modules/mbedtls/crypto_mbedtls.h
@@ -101,12 +101,31 @@ public:
 	friend class SSLContextMbedTLS;
 };
 
+class HMACContextMbedTLS : public HMACContext {
+private:
+	HashingContext::HashType hash_type;
+	int hash_len = 0;
+	void *ctx = nullptr;
+
+public:
+	static HMACContext *create();
+	static void make_default() { HMACContext::_create = create; }
+	static void finalize() { HMACContext::_create = nullptr; }
+
+	static bool is_md_type_allowed(mbedtls_md_type_t p_md_type);
+
+	virtual Error start(HashingContext::HashType p_hash_type, PackedByteArray p_key);
+	virtual Error update(PackedByteArray p_data);
+	virtual PackedByteArray finish();
+
+	HMACContextMbedTLS() {}
+};
+
 class CryptoMbedTLS : public Crypto {
 private:
 	mbedtls_entropy_context entropy;
 	mbedtls_ctr_drbg_context ctr_drbg;
 	static X509CertificateMbedTLS *default_certs;
-	mbedtls_md_type_t _md_type_from_hashtype(HashingContext::HashType p_hash_type, int &r_size);
 
 public:
 	static Crypto *create();
@@ -114,6 +133,7 @@ public:
 	static void finalize_crypto();
 	static X509CertificateMbedTLS *get_default_certificates();
 	static void load_default_certificates(String p_path);
+	static mbedtls_md_type_t md_type_from_hashtype(HashingContext::HashType p_hash_type, int &r_size);
 
 	virtual PackedByteArray generate_random_bytes(int p_bytes);
 	virtual Ref<CryptoKey> generate_rsa(int p_bytes);
diff --git a/modules/mbedtls/register_types.cpp b/modules/mbedtls/register_types.cpp
index 84a27c29bd..59abbac8ec 100644
--- a/modules/mbedtls/register_types.cpp
+++ b/modules/mbedtls/register_types.cpp
@@ -35,6 +35,10 @@
 #include "packet_peer_mbed_dtls.h"
 #include "stream_peer_mbedtls.h"
 
+#ifdef TESTS_ENABLED
+#include "tests/test_crypto_mbedtls.h"
+#endif
+
 void register_mbedtls_types() {
 	CryptoMbedTLS::initialize_crypto();
 	StreamPeerMbedTLS::initialize_ssl();
diff --git a/modules/mbedtls/tests/test_crypto_mbedtls.cpp b/modules/mbedtls/tests/test_crypto_mbedtls.cpp
new file mode 100644
index 0000000000..c5a27aa794
--- /dev/null
+++ b/modules/mbedtls/tests/test_crypto_mbedtls.cpp
@@ -0,0 +1,62 @@
+/*************************************************************************/
+/*  test_crypto_mbedtls.cpp                                              */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* 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 "modules/mbedtls/tests/test_crypto_mbedtls.h"
+
+#include "modules/mbedtls/crypto_mbedtls.h"
+#include "tests/test_macros.h"
+
+namespace TestCryptoMbedTLS {
+
+void hmac_digest_test(HashingContext::HashType ht, String expected_hex) {
+	CryptoMbedTLS crypto;
+	PackedByteArray key = String("supersecretkey").to_utf8_buffer();
+	PackedByteArray msg = String("Return of the MAC!").to_utf8_buffer();
+	PackedByteArray digest = crypto.hmac_digest(ht, key, msg);
+	String hex = String::hex_encode_buffer(digest.ptr(), digest.size());
+	CHECK(hex == expected_hex);
+}
+
+void hmac_context_digest_test(HashingContext::HashType ht, String expected_hex) {
+	HMACContextMbedTLS ctx;
+	PackedByteArray key = String("supersecretkey").to_utf8_buffer();
+	PackedByteArray msg1 = String("Return of ").to_utf8_buffer();
+	PackedByteArray msg2 = String("the MAC!").to_utf8_buffer();
+	Error err = ctx.start(ht, key);
+	CHECK(err == OK);
+	err = ctx.update(msg1);
+	CHECK(err == OK);
+	err = ctx.update(msg2);
+	CHECK(err == OK);
+	PackedByteArray digest = ctx.finish();
+	String hex = String::hex_encode_buffer(digest.ptr(), digest.size());
+	CHECK(hex == expected_hex);
+}
+} // namespace TestCryptoMbedTLS
diff --git a/modules/mbedtls/tests/test_crypto_mbedtls.h b/modules/mbedtls/tests/test_crypto_mbedtls.h
new file mode 100644
index 0000000000..7b1e062239
--- /dev/null
+++ b/modules/mbedtls/tests/test_crypto_mbedtls.h
@@ -0,0 +1,61 @@
+/*************************************************************************/
+/*  test_crypto_mbedtls.h                                                */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* 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.                */
+/*************************************************************************/
+
+#ifndef TEST_CRYPTO_MBEDTLS_H
+#define TEST_CRYPTO_MBEDTLS_H
+
+#include "core/crypto/hashing_context.h"
+
+#include "tests/test_macros.h"
+
+namespace TestCryptoMbedTLS {
+
+void hmac_digest_test(HashingContext::HashType ht, String expected_hex);
+
+TEST_CASE("[CryptoMbedTLS] HMAC digest") {
+	// SHA-256
+	hmac_digest_test(HashingContext::HashType::HASH_SHA256, "fe442023f8a7d36a810e1e7cd8a8e2816457f350a008fbf638296afa12085e59");
+
+	// SHA-1
+	hmac_digest_test(HashingContext::HashType::HASH_SHA1, "a0ac4cd68a2f4812c355983d94e8d025afe7dddf");
+}
+
+void hmac_context_digest_test(HashingContext::HashType ht, String expected_hex);
+
+TEST_CASE("[HMACContext] HMAC digest") {
+	// SHA-256
+	hmac_context_digest_test(HashingContext::HashType::HASH_SHA256, "fe442023f8a7d36a810e1e7cd8a8e2816457f350a008fbf638296afa12085e59");
+
+	// SHA-1
+	hmac_context_digest_test(HashingContext::HashType::HASH_SHA1, "a0ac4cd68a2f4812c355983d94e8d025afe7dddf");
+}
+} // namespace TestCryptoMbedTLS
+
+#endif // TEST_CRYPTO_MBEDTLS_H