Merge pull request #57887 from Faless/crypto/4.x_os_get_entropy

6 files changed, 78 insertions, 20 deletions

diff --git a/core/crypto/SCsub b/core/crypto/SCsub
index 1fe2fa5b23..9b7953fdc5 100644
--- a/core/crypto/SCsub
+++ b/core/crypto/SCsub
@@ -31,6 +31,8 @@ if not has_module:
         "aes.c",
         "base64.c",
         "constant_time.c",
+        "ctr_drbg.c",
+        "entropy.c",
         "md5.c",
         "sha1.c",
         "sha256.c",
diff --git a/core/crypto/crypto_core.cpp b/core/crypto/crypto_core.cpp
index 9f000c5aeb..3cf7b6c310 100644
--- a/core/crypto/crypto_core.cpp
+++ b/core/crypto/crypto_core.cpp
@@ -30,12 +30,55 @@
 
 #include "crypto_core.h"
 
+#include "core/os/os.h"
+
 #include <mbedtls/aes.h>
 #include <mbedtls/base64.h>
+#include <mbedtls/ctr_drbg.h>
+#include <mbedtls/entropy.h>
 #include <mbedtls/md5.h>
 #include <mbedtls/sha1.h>
 #include <mbedtls/sha256.h>
 
+// RandomGenerator
+CryptoCore::RandomGenerator::RandomGenerator() {
+	entropy = memalloc(sizeof(mbedtls_entropy_context));
+	mbedtls_entropy_init((mbedtls_entropy_context *)entropy);
+	mbedtls_entropy_add_source((mbedtls_entropy_context *)entropy, &CryptoCore::RandomGenerator::_entropy_poll, nullptr, 256, MBEDTLS_ENTROPY_SOURCE_STRONG);
+	ctx = memalloc(sizeof(mbedtls_ctr_drbg_context));
+	mbedtls_ctr_drbg_init((mbedtls_ctr_drbg_context *)ctx);
+}
+
+CryptoCore::RandomGenerator::~RandomGenerator() {
+	mbedtls_ctr_drbg_free((mbedtls_ctr_drbg_context *)ctx);
+	memfree(ctx);
+	mbedtls_entropy_free((mbedtls_entropy_context *)entropy);
+	memfree(entropy);
+}
+
+int CryptoCore::RandomGenerator::_entropy_poll(void *p_data, unsigned char *r_buffer, size_t p_len, size_t *r_len) {
+	*r_len = 0;
+	Error err = OS::get_singleton()->get_entropy(r_buffer, p_len);
+	ERR_FAIL_COND_V(err, MBEDTLS_ERR_ENTROPY_SOURCE_FAILED);
+	*r_len = p_len;
+	return 0;
+}
+
+Error CryptoCore::RandomGenerator::init() {
+	int ret = mbedtls_ctr_drbg_seed((mbedtls_ctr_drbg_context *)ctx, mbedtls_entropy_func, (mbedtls_entropy_context *)entropy, nullptr, 0);
+	if (ret) {
+		ERR_FAIL_COND_V_MSG(ret, FAILED, " failed\n  ! mbedtls_ctr_drbg_seed returned an error" + itos(ret));
+	}
+	return OK;
+}
+
+Error CryptoCore::RandomGenerator::get_random_bytes(uint8_t *r_buffer, size_t p_bytes) {
+	ERR_FAIL_COND_V(!ctx, ERR_UNCONFIGURED);
+	int ret = mbedtls_ctr_drbg_random((mbedtls_ctr_drbg_context *)ctx, r_buffer, p_bytes);
+	ERR_FAIL_COND_V_MSG(ret, FAILED, " failed\n  ! mbedtls_ctr_drbg_seed returned an error" + itos(ret));
+	return OK;
+}
+
 // MD5
 CryptoCore::MD5Context::MD5Context() {
 	ctx = memalloc(sizeof(mbedtls_md5_context));
diff --git a/core/crypto/crypto_core.h b/core/crypto/crypto_core.h
index 355f4a2404..eacef268cc 100644
--- a/core/crypto/crypto_core.h
+++ b/core/crypto/crypto_core.h
@@ -35,9 +35,24 @@
 
 class CryptoCore {
 public:
+	class RandomGenerator {
+	private:
+		void *entropy = nullptr;
+		void *ctx = nullptr;
+
+		static int _entropy_poll(void *p_data, unsigned char *r_buffer, size_t p_len, size_t *r_len);
+
+	public:
+		RandomGenerator();
+		~RandomGenerator();
+
+		Error init();
+		Error get_random_bytes(uint8_t *r_buffer, size_t p_bytes);
+	};
+
 	class MD5Context {
 	private:
-		void *ctx = nullptr; // To include, or not to include...
+		void *ctx = nullptr;
 
 	public:
 		MD5Context();
@@ -50,7 +65,7 @@ public:
 
 	class SHA1Context {
 	private:
-		void *ctx = nullptr; // To include, or not to include...
+		void *ctx = nullptr;
 
 	public:
 		SHA1Context();
@@ -63,7 +78,7 @@ public:
 
 	class SHA256Context {
 	private:
-		void *ctx = nullptr; // To include, or not to include...
+		void *ctx = nullptr;
 
 	public:
 		SHA256Context();
@@ -76,7 +91,7 @@ public:
 
 	class AESContext {
 	private:
-		void *ctx = nullptr; // To include, or not to include...
+		void *ctx = nullptr;
 
 	public:
 		AESContext();
diff --git a/core/io/resource_uid.cpp b/core/io/resource_uid.cpp
index 776756e64e..d0335bed3a 100644
--- a/core/io/resource_uid.cpp
+++ b/core/io/resource_uid.cpp
@@ -31,7 +31,7 @@
 #include "resource_uid.h"
 
 #include "core/config/project_settings.h"
-#include "core/crypto/crypto.h"
+#include "core/crypto/crypto_core.h"
 #include "core/io/dir_access.h"
 #include "core/io/file_access.h"
 
@@ -82,20 +82,14 @@ ResourceUID::ID ResourceUID::text_to_id(const String &p_text) const {
 	return ID(uid & 0x7FFFFFFFFFFFFFFF);
 }
 
-ResourceUID::ID ResourceUID::create_id() const {
-	mutex.lock();
-	if (crypto.is_null()) {
-		crypto = Ref<Crypto>(Crypto::create());
-	}
-	mutex.unlock();
+ResourceUID::ID ResourceUID::create_id() {
 	while (true) {
-		PackedByteArray bytes = crypto->generate_random_bytes(8);
-		ERR_FAIL_COND_V(bytes.size() != 8, INVALID_ID);
-		const uint64_t *ptr64 = (const uint64_t *)bytes.ptr();
-		ID id = int64_t((*ptr64) & 0x7FFFFFFFFFFFFFFF);
-		mutex.lock();
+		ID id = INVALID_ID;
+		MutexLock lock(mutex);
+		Error err = ((CryptoCore::RandomGenerator *)crypto)->get_random_bytes((uint8_t *)&id, sizeof(id));
+		ERR_FAIL_COND_V(err != OK, INVALID_ID);
+		id &= 0x7FFFFFFFFFFFFFFF;
 		bool exists = unique_ids.has(id);
-		mutex.unlock();
 		if (!exists) {
 			return id;
 		}
@@ -261,6 +255,9 @@ ResourceUID *ResourceUID::singleton = nullptr;
 ResourceUID::ResourceUID() {
 	ERR_FAIL_COND(singleton != nullptr);
 	singleton = this;
+	crypto = memnew(CryptoCore::RandomGenerator);
+	((CryptoCore::RandomGenerator *)crypto)->init();
 }
 ResourceUID::~ResourceUID() {
+	memdelete((CryptoCore::RandomGenerator *)crypto);
 }
diff --git a/core/io/resource_uid.h b/core/io/resource_uid.h
index 9f2ab5245b..1ea44b9d06 100644
--- a/core/io/resource_uid.h
+++ b/core/io/resource_uid.h
@@ -35,7 +35,6 @@
 #include "core/string/string_name.h"
 #include "core/templates/ordered_hash_map.h"
 
-class Crypto;
 class ResourceUID : public Object {
 	GDCLASS(ResourceUID, Object)
 public:
@@ -47,7 +46,7 @@ public:
 	static String get_cache_file();
 
 private:
-	mutable Ref<Crypto> crypto;
+	void *crypto; // CryptoCore::RandomGenerator (avoid including crypto_core.h)
 	Mutex mutex;
 	struct Cache {
 		CharString cs;
@@ -67,7 +66,7 @@ public:
 	String id_to_text(ID p_id) const;
 	ID text_to_id(const String &p_text) const;
 
-	ID create_id() const;
+	ID create_id();
 	bool has_id(ID p_id) const;
 	void add_id(ID p_id, const String &p_path);
 	void set_id(ID p_id, const String &p_path);
diff --git a/core/os/os.h b/core/os/os.h
index d3d2a868fa..188900a070 100644
--- a/core/os/os.h
+++ b/core/os/os.h
@@ -132,6 +132,8 @@ public:
 
 	virtual String get_stdin_string(bool p_block = true) = 0;
 
+	virtual Error get_entropy(uint8_t *r_buffer, int p_bytes) = 0; // Should return cryptographically-safe random bytes.
+
 	virtual PackedStringArray get_connected_midi_inputs();
 	virtual void open_midi_inputs();
 	virtual void close_midi_inputs();