xorg-x11-server-Xwayland/0007-composite-Handle-failure-to-redirect-in-compRedirect.patch

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From 40efa6359cd184d6d1413f02e4418c9930c73f88 Mon Sep 17 00:00:00 2001
From: Olivier Fourdan <ofourdan@redhat.com>
Date: Tue, 17 Dec 2024 15:19:45 +0100
Subject: [PATCH xserver 07/13] composite: Handle failure to redirect in
compRedirectWindow()
The function compCheckRedirect() may fail if it cannot allocate the
backing pixmap.
In that case, compRedirectWindow() will return a BadAlloc error.
However that failure code path will shortcut the validation of the
window tree marked just before, which leaves the validate data partly
initialized.
That causes a use of uninitialized pointer later.
The fix is to not shortcut the call to compHandleMarkedWindows() even in
the case of compCheckRedirect() returning an error.
CVE-2025-26599, ZDI-CAN-25851
This vulnerability was discovered by:
Jan-Niklas Sohn working with Trend Micro Zero Day Initiative
Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Acked-by: Peter Hutterer <peter.hutterer@who-t.net>
(cherry picked from commit c1ff84bef2569b4ba4be59323cf575d1798ba9be)
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1831>
---
composite/compalloc.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/composite/compalloc.c b/composite/compalloc.c
index acd215002..83894aa1f 100644
--- a/composite/compalloc.c
+++ b/composite/compalloc.c
@@ -140,6 +140,7 @@ compRedirectWindow(ClientPtr pClient, WindowPtr pWin, int update)
CompScreenPtr cs = GetCompScreen(pWin->drawable.pScreen);
WindowPtr pLayerWin;
Bool anyMarked = FALSE;
+ int status = Success;
if (pWin == cs->pOverlayWin) {
return Success;
@@ -218,13 +219,13 @@ compRedirectWindow(ClientPtr pClient, WindowPtr pWin, int update)
if (!compCheckRedirect(pWin)) {
FreeResource(ccw->id, RT_NONE);
- return BadAlloc;
+ status = BadAlloc;
}
if (anyMarked)
compHandleMarkedWindows(pWin, pLayerWin);
- return Success;
+ return status;
}
void
--
2.48.1