From 335e8a6d128646e5a19d39dfc677f5a5a555f7cc Mon Sep 17 00:00:00 2001
From: Ben Noordhuis <info@bnoordhuis.nl>
Date: Mon, 6 Apr 2020 12:36:34 +0200
Subject: [PATCH] win: use RtlGenRandom from advapi32.dll directly

At least two people have reported that `LoadLibrary("advapi32.dll")`
fails in some configurations.

Libuv already links against advapi32.dll so let's sidestep the issue
by linking to `RtlGenRandom()` directly instead of looking it up at
runtime.

Fixes: https://github.com/libuv/libuv/issues/2759
PR-URL: https://github.com/libuv/libuv/pull/2762
Reviewed-By: Bartosz Sosnowski <bartosz@janeasystems.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Jameson Nash <vtjnash@gmail.com>
---
 src/win/util.c   |  8 ++++----
 src/win/winapi.c | 12 ------------
 src/win/winapi.h |  8 --------
 3 files changed, 4 insertions(+), 24 deletions(-)

diff --git a/src/win/util.c b/src/win/util.c
index 4de638f5..34a898bf 100644
--- a/src/win/util.c
+++ b/src/win/util.c
@@ -63,6 +63,9 @@
 /* Maximum environment variable size, including the terminating null */
 #define MAX_ENV_VAR_LENGTH 32767
 
+/* A RtlGenRandom() by any other name... */
+extern BOOLEAN NTAPI SystemFunction036(PVOID Buffer, ULONG BufferLength);
+
 /* Cached copy of the process title, plus a mutex guarding it. */
 static char *process_title;
 static CRITICAL_SECTION process_title_lock;
@@ -1862,13 +1865,10 @@ int uv_gettimeofday(uv_timeval64_t* tv) {
 }
 
 int uv__random_rtlgenrandom(void* buf, size_t buflen) {
-  if (pRtlGenRandom == NULL)
-    return UV_ENOSYS;
-
   if (buflen == 0)
     return 0;
 
-  if (pRtlGenRandom(buf, buflen) == FALSE)
+  if (SystemFunction036(buf, buflen) == FALSE)
     return UV_EIO;
 
   return 0;
diff --git a/src/win/winapi.c b/src/win/winapi.c
index 85a9de8a..bb86ec8c 100644
--- a/src/win/winapi.c
+++ b/src/win/winapi.c
@@ -36,9 +36,6 @@ sNtQueryDirectoryFile pNtQueryDirectoryFile;
 sNtQuerySystemInformation pNtQuerySystemInformation;
 sNtQueryInformationProcess pNtQueryInformationProcess;
 
-/* Advapi32 function pointers */
-sRtlGenRandom pRtlGenRandom;
-
 /* Kernel32 function pointers */
 sGetQueuedCompletionStatusEx pGetQueuedCompletionStatusEx;
 
@@ -54,7 +51,6 @@ void uv_winapi_init(void) {
   HMODULE powrprof_module;
   HMODULE user32_module;
   HMODULE kernel32_module;
-  HMODULE advapi32_module;
 
   ntdll_module = GetModuleHandleA("ntdll.dll");
   if (ntdll_module == NULL) {
@@ -138,12 +134,4 @@ void uv_winapi_init(void) {
     pSetWinEventHook = (sSetWinEventHook)
       GetProcAddress(user32_module, "SetWinEventHook");
   }
-
-  advapi32_module = GetModuleHandleA("advapi32.dll");
-  if (advapi32_module == NULL) {
-    uv_fatal_error(GetLastError(), "GetModuleHandleA");
-  }
-
-  pRtlGenRandom =
-      (sRtlGenRandom) GetProcAddress(advapi32_module, "SystemFunction036");
 }
diff --git a/src/win/winapi.h b/src/win/winapi.h
index fcc70652..322a212d 100644
--- a/src/win/winapi.h
+++ b/src/win/winapi.h
@@ -4589,11 +4589,6 @@ typedef NTSTATUS (NTAPI *sNtQueryInformationProcess)
                   ULONG Length,
                   PULONG ReturnLength);
 
-/*
- * Advapi32 headers
- */
-typedef BOOLEAN (WINAPI *sRtlGenRandom)(PVOID Buffer, ULONG BufferLength);
-
 /*
  * Kernel32 headers
  */
@@ -4736,9 +4731,6 @@ extern sNtQueryDirectoryFile pNtQueryDirectoryFile;
 extern sNtQuerySystemInformation pNtQuerySystemInformation;
 extern sNtQueryInformationProcess pNtQueryInformationProcess;
 
-/* Advapi32 function pointers */
-extern sRtlGenRandom pRtlGenRandom;
-
 /* Kernel32 function pointers */
 extern sGetQueuedCompletionStatusEx pGetQueuedCompletionStatusEx;