rpccookieperms: Set permissions on temporary file, prior to writing the cookie

Github-Pull: na
Rebased-From: 74cc11bbde33dad0f4856731bf16cb674069b3c4

Author: luke-jr

src/rpc/request.cpp

@@ -117,6 +117,16 @@ bool GenerateAuthCookie(std::string* cookie_out, std::optional<fs::perms> cookie
         LogWarning("Unable to open cookie authentication file %s for writing", fs::PathToString(filepath_tmp));
         return false;
     }
+
+    if (cookie_perms) {
+        std::error_code code;
+        fs::permissions(filepath_tmp, cookie_perms.value(), fs::perm_options::replace, code);
+        if (code) {
+            LogWarning("Unable to set permissions on cookie authentication file %s", fs::PathToString(filepath_tmp));
+            return false;
+        }
+    }
+
     file << cookie;
     file.close();
 
@@ -125,14 +135,6 @@ bool GenerateAuthCookie(std::string* cookie_out, std::optional<fs::perms> cookie
         LogWarning("Unable to rename cookie authentication file %s to %s", fs::PathToString(filepath_tmp), fs::PathToString(filepath));
         return false;
     }
-    if (cookie_perms) {
-        std::error_code code;
-        fs::permissions(filepath, cookie_perms.value(), fs::perm_options::replace, code);
-        if (code) {
-            LogWarning("Unable to set permissions on cookie authentication file %s", fs::PathToString(filepath));
-            return false;
-        }
-    }
 
     g_generated_cookie = true;
     LogInfo("Generated RPC authentication cookie %s\n", fs::PathToString(filepath));