From a9e27cf240875f527a16c86fd911a214425bce74 Mon Sep 17 00:00:00 2001
From: "Enrico Weigelt, metux IT consult" <info@metux.net>
Date: Tue, 19 Aug 2025 19:21:25 +0200
Subject: [PATCH] [PR #796] xkb: ProcXkbGetKbdByName(): extra payload size
 sanity check

PR: https://github.com/X11Libre/xserver/pull/796
---
 xkb/xkb.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/xkb/xkb.c b/xkb/xkb.c
index ba1ee1d4bb..dc92d66dd9 100644
--- a/xkb/xkb.c
+++ b/xkb/xkb.c
@@ -6090,6 +6090,10 @@ ProcXkbGetKbdByName(ClientPtr client)
 
         XkbAssembleGeometry(client, new->geom, grep, &childbuf);
 
+        if (childbuf.wpos != (grep.length * 4))
+            LogMessage(X_WARNING, "ProcXkbGetKbdByName() childbuf size (%ld) mismatch nrep size (%ld // %d units)\n",
+                       (unsigned long)childbuf.wpos, (unsigned long)grep.length * 4, grep.length);
+
         if (client->swapped) {
             swaps(&grep.sequenceNumber);
             swapl(&grep.length);