From 9467c8951a01f58e1d50e163fbedc85370786981 Mon Sep 17 00:00:00 2001
From: UnknownShadow200 <unknownshadow200@gmail.com>
Date: Tue, 17 Dec 2024 19:50:39 +1100
Subject: [PATCH] WIP on implementing entropy generation

---
 src/Platform_3DS.c     |  5 +++++
 src/Platform_Posix.c   |  8 +++++++-
 src/SSL.c              | 17 +++--------------
 src/_PlatformConsole.h |  2 ++
 4 files changed, 17 insertions(+), 15 deletions(-)

diff --git a/src/Platform_3DS.c b/src/Platform_3DS.c
index d0d50ba91..c9f422336 100644
--- a/src/Platform_3DS.c
+++ b/src/Platform_3DS.c
@@ -459,4 +459,9 @@ static cc_result GetMachineID(cc_uint32* key) {
 	Mem_Copy(key, MACHINE_KEY, sizeof(MACHINE_KEY) - 1);
 	return 0;
 }
+
+cc_result Platform_GetEntropy(void* data, int len) {
+	return PS_GenerateRandomBytes(data, len);
+	// NOTE: PS_GenerateRandomBytes isn't implemented in Citra
+}
 #endif
diff --git a/src/Platform_Posix.c b/src/Platform_Posix.c
index cfd0e0c39..177422fb7 100644
--- a/src/Platform_Posix.c
+++ b/src/Platform_Posix.c
@@ -1605,7 +1605,13 @@ cc_result Platform_Decrypt(const void* data, int len, cc_string* dst) {
 }
 
 cc_result Platform_GetEntropy(void* data, int len) {
-	return ERR_NOT_SUPPORTED;
+	int fd = open("/dev/urandom", O_RDONLY);
+	if (fd < 0) return ERR_NOT_SUPPORTED;
+	
+	// TODO: check return code? and partial reads?
+	read(fd, data, len);
+	close(fd);
+	return 0;
 }
 
 
diff --git a/src/SSL.c b/src/SSL.c
index 12369d574..77cf9b3ac 100644
--- a/src/SSL.c
+++ b/src/SSL.c
@@ -446,24 +446,13 @@ cc_bool SSLBackend_DescribeError(cc_result res, cc_string* dst) {
 	return false; // TODO: error codes 
 }
 
-#if defined CC_BUILD_3DS
-#include <3ds.h>
 static void InjectEntropy(SSLContext* ctx) {
 	char buf[32];
-	PS_GenerateRandomBytes(buf, 32);
-	// NOTE: PS_GenerateRandomBytes isn't implemented in Citra
-	
+	cc_result res = Platform_GetEntropy(buf, 32);
+	if (res) Platform_LogConst("SSL: Using insecure uninitialised stack data for entropy");
+
 	br_ssl_engine_inject_entropy(&ctx->sc.eng, buf, 32);
 }
-#else
-#warning "Using uninitialised stack data for entropy. This should be replaced with actual cryptographic RNG data"
-static void InjectEntropy(SSLContext* ctx) {
-	char buf[32];
-	// TODO: Use actual APIs to retrieve random data
-	
-	br_ssl_engine_inject_entropy(&ctx->sc.eng, buf, 32);
-}
-#endif
 
 static void SetCurrentTime(SSLContext* ctx) {
 	cc_uint64 cur = DateTime_CurrentUTC();
diff --git a/src/_PlatformConsole.h b/src/_PlatformConsole.h
index 634e2f97f..e42c52e84 100644
--- a/src/_PlatformConsole.h
+++ b/src/_PlatformConsole.h
@@ -196,6 +196,8 @@ cc_result Platform_Decrypt(const void* data, int len, cc_string* dst) {
 	return 0;
 }
 
+#ifndef CC_BUILD_3DS
 cc_result Platform_GetEntropy(void* data, int len) {
 	return ERR_NOT_SUPPORTED;
 }
+#endif