xwayland: fix CVE-2025-49177

A flaw was found in the XFIXES extension. The XFixesSetClientDisconnectMode handler
does not validate the request length, allowing a client to read unintended memory
from previous requests

(From OE-Core rev: 0b2afd59ce8c35083c1cb3596a2f7d4eaa7bd1c8)

Signed-off-by: Archana Polampalli <archana.polampalli@windriver.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>

meta/recipes-graphics/xwayland/xwayland/CVE-2025-49177.patch

@@ -0,0 +1,55 @@
+From ab02fb96b1c701c3bb47617d965522c34befa6af Mon Sep 17 00:00:00 2001
+From: Olivier Fourdan <ofourdan@redhat.com>
+Date: Mon, 28 Apr 2025 10:05:36 +0200
+Subject: [PATCH] xfixes: Check request length for SetClientDisconnectMode
+
+The handler of XFixesSetClientDisconnectMode does not check the client
+request length.
+
+A client could send a shorter request and read data from a former
+request.
+
+Fix the issue by checking the request size matches.
+
+CVE-2025-49177
+
+This issue was discovered by Nils Emmerich <nemmerich@ernw.de> and
+reported by Julian Suleder via ERNW Vulnerability Disclosure.
+
+Fixes: e167299f6 - xfixes: Add ClientDisconnectMode
+Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
+Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
+Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/2024>
+
+CVE: CVE-2025-49177
+
+Upstream-Status: Backport [https://gitlab.freedesktop.org/xorg/xserver/-/commit/ab02fb96b1c701c3bb47617d965522c34befa6af]
+
+Signed-off-by: Archana Polampalli <archana.polampalli@windriver.com>
+---
+ xfixes/disconnect.c | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+diff --git a/xfixes/disconnect.c b/xfixes/disconnect.c
+index 28aac45..d6da1f9 100644
+--- a/xfixes/disconnect.c
++++ b/xfixes/disconnect.c
+@@ -67,6 +67,7 @@ ProcXFixesSetClientDisconnectMode(ClientPtr client)
+     ClientDisconnectPtr pDisconnect = GetClientDisconnect(client);
+
+     REQUEST(xXFixesSetClientDisconnectModeReq);
++    REQUEST_SIZE_MATCH(xXFixesSetClientDisconnectModeReq);
+
+     pDisconnect->disconnect_mode = stuff->disconnect_mode;
+
+@@ -80,7 +81,7 @@ SProcXFixesSetClientDisconnectMode(ClientPtr client)
+
+     swaps(&stuff->length);
+
+-    REQUEST_AT_LEAST_SIZE(xXFixesSetClientDisconnectModeReq);
++    REQUEST_SIZE_MATCH(xXFixesSetClientDisconnectModeReq);
+
+     swapl(&stuff->disconnect_mode);
+
+--
+2.40.0

meta/recipes-graphics/xwayland/xwayland_23.2.5.bb

@@ -27,6 +27,7 @@ SRC_URI = "https://www.x.org/archive/individual/xserver/xwayland-${PV}.tar.xz \
            file://CVE-2025-49175.patch \
            file://CVE-2025-49176-0001.patch \
            file://CVE-2025-49176-0002.patch \
+           file://CVE-2025-49177.patch \
 "
 SRC_URI[sha256sum] = "33ec7ff2687a59faaa52b9b09aa8caf118e7ecb6aed8953f526a625ff9f4bd90"