From 1b1e2317ff073b04a5ecd55574d2dc1edcdf1d50 Mon Sep 17 00:00:00 2001
From: matt335672 <30179339+matt335672@users.noreply.github.com>
Date: Fri, 29 Aug 2025 11:33:19 +0100
Subject: [PATCH] xrdp: Don't try to drop privs if we are already unprivileged

---
 xrdp/xrdp.c | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/xrdp/xrdp.c b/xrdp/xrdp.c
index e41be7d1..bd41b4e5 100644
--- a/xrdp/xrdp.c
+++ b/xrdp/xrdp.c
@@ -426,14 +426,30 @@ check_drop_privileges(struct xrdp_startup_params *startup_params)
     int rv = 1;
     const char *user = startup_params->runtime_user;
     const char *group = startup_params->runtime_group;
+    int entry_uid = g_getuid();
+    int entry_gid = g_getgid();
 
-    if (user[0] == '\0' && group[0] == '\0')
+    // Regard a user as privileged if either the UID or GID is zero
+    int privileged_user = (entry_uid == 0 || entry_gid == 0);
+    if (!privileged_user)
     {
-        // Allow this for now
-        LOG(LOG_LEVEL_ALWAYS,
-            "You are running xrdp as root. This is not safe.");
+        // xrdp daemon UID:GID is already set by whatever started it. We'll
+        // log this as it may be unexpected and continue. We don't have
+        // any privilege to override this.
+        LOG(LOG_LEVEL_INFO,
+            "xrdp is already running as an unprivileged user uid=%d gid=%d",
+            entry_uid, entry_gid);
         rv = 0;
     }
+    else if (user[0] == '\0' && group[0] == '\0')
+    {
+        // We're running as a privileged user, and this isn't
+        // overridden in our own config
+        LOG(LOG_LEVEL_ALWAYS,
+            "You are running xrdp as uid=%d gid=%d. This is not safe.",
+            entry_uid, entry_gid);
+        rv = 0; // Allowed for now for old configs
+    }
     else if (user[0] == '\0' || group[0] == '\0')
     {
         LOG(LOG_LEVEL_ERROR,