From 0aa6de6debbc67cf5ec852677e6d341e720e4bc5 Mon Sep 17 00:00:00 2001
From: Kyle Farnung <kfarnung@microsoft.com>
Date: Fri, 20 Apr 2018 10:03:26 -0700
Subject: [PATCH] win: fix registry API error handling

The Reg* APIs on Windows don't use GetLastError() to report
failures. The errors are returned directly from the call.

For systems which don't have one of the values GetLastError() can
end up returning 0 to the caller, indicating success. The caller
then assumes that the data is valid and can attempt to execute on
garbage data. This change fixes the flow to correctly return the
error to the caller.

PR-URL: https://github.com/libuv/libuv/pull/1811
Reviewed-By: Bartosz Sosnowski <bartosz@janeasystems.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
---
 src/win/util.c | 43 +++++++++++++++++++++----------------------
 1 file changed, 21 insertions(+), 22 deletions(-)

diff --git a/src/win/util.c b/src/win/util.c
index 6b2bc2d72..5d1c812dd 100644
--- a/src/win/util.c
+++ b/src/win/util.c
@@ -615,7 +615,7 @@ int uv_cpu_info(uv_cpu_info_t** cpu_infos_ptr, int* cpu_count_ptr) {
   SYSTEM_PROCESSOR_PERFORMANCE_INFORMATION* sppi;
   DWORD sppi_size;
   SYSTEM_INFO system_info;
-  DWORD cpu_count, r, i;
+  DWORD cpu_count, i;
   NTSTATUS status;
   ULONG result_size;
   int err;
@@ -670,34 +670,33 @@ int uv_cpu_info(uv_cpu_info_t** cpu_infos_ptr, int* cpu_count_ptr) {
 
     assert(len > 0 && len < ARRAY_SIZE(key_name));
 
-    r = RegOpenKeyExW(HKEY_LOCAL_MACHINE,
-                      key_name,
-                      0,
-                      KEY_QUERY_VALUE,
-                      &processor_key);
-    if (r != ERROR_SUCCESS) {
-      err = GetLastError();
+    err = RegOpenKeyExW(HKEY_LOCAL_MACHINE,
+                        key_name,
+                        0,
+                        KEY_QUERY_VALUE,
+                        &processor_key);
+    if (err != ERROR_SUCCESS) {
       goto error;
     }
 
-    if (RegQueryValueExW(processor_key,
-                         L"~MHz",
-                         NULL,
-                         NULL,
-                         (BYTE*) &cpu_speed,
-                         &cpu_speed_size) != ERROR_SUCCESS) {
-      err = GetLastError();
+    err = RegQueryValueExW(processor_key,
+                           L"~MHz",
+                           NULL,
+                           NULL,
+                           (BYTE*)&cpu_speed,
+                           &cpu_speed_size);
+    if (err != ERROR_SUCCESS) {
       RegCloseKey(processor_key);
       goto error;
     }
 
-    if (RegQueryValueExW(processor_key,
-                         L"ProcessorNameString",
-                         NULL,
-                         NULL,
-                         (BYTE*) &cpu_brand,
-                         &cpu_brand_size) != ERROR_SUCCESS) {
-      err = GetLastError();
+    err = RegQueryValueExW(processor_key,
+                           L"ProcessorNameString",
+                           NULL,
+                           NULL,
+                           (BYTE*)&cpu_brand,
+                           &cpu_brand_size);
+    if (err != ERROR_SUCCESS) {
       RegCloseKey(processor_key);
       goto error;
     }