diff --git a/U_xserver-composite-Fix-use-after-free-of-the-COW.patch b/U_xserver-composite-Fix-use-after-free-of-the-COW.patch new file mode 100644 index 0000000..3473094 --- /dev/null +++ b/U_xserver-composite-Fix-use-after-free-of-the-COW.patch @@ -0,0 +1,42 @@ +From 947bd1b3f4a23565bf10879ec41ba06ebe1e1c76 Mon Sep 17 00:00:00 2001 +From: Olivier Fourdan +Date: Mon, 13 Mar 2023 11:08:47 +0100 +Subject: [PATCH xserver] composite: Fix use-after-free of the COW + +ZDI-CAN-19866/CVE-2023-1393 + +If a client explicitly destroys the compositor overlay window (aka COW), +we would leave a dangling pointer to that window in the CompScreen +structure, which will trigger a use-after-free later. + +Make sure to clear the CompScreen pointer to the COW when the latter gets +destroyed explicitly by the client. + +This vulnerability was discovered by: +Jan-Niklas Sohn working with Trend Micro Zero Day Initiative + +Signed-off-by: Olivier Fourdan +Reviewed-by: Adam Jackson +--- + composite/compwindow.c | 5 +++++ + 1 file changed, 5 insertions(+) + +diff --git a/composite/compwindow.c b/composite/compwindow.c +index 4e2494b86..b30da589e 100644 +--- a/composite/compwindow.c ++++ b/composite/compwindow.c +@@ -620,6 +620,11 @@ compDestroyWindow(WindowPtr pWin) + ret = (*pScreen->DestroyWindow) (pWin); + cs->DestroyWindow = pScreen->DestroyWindow; + pScreen->DestroyWindow = compDestroyWindow; ++ ++ /* Did we just destroy the overlay window? */ ++ if (pWin == cs->pOverlayWin) ++ cs->pOverlayWin = NULL; ++ + /* compCheckTree (pWin->drawable.pScreen); can't check -- tree isn't good*/ + return ret; + } +-- +2.40.0 + diff --git a/xwayland.changes b/xwayland.changes index bc111ea..6c0549d 100644 --- a/xwayland.changes +++ b/xwayland.changes @@ -1,3 +1,10 @@ +------------------------------------------------------------------- +Thu Mar 23 12:32:18 UTC 2023 - Stefan Dirsch + +- U_xserver-composite-Fix-use-after-free-of-the-COW.patch + * overlay window use-after-free (CVE-2023-1393, ZDI-CAN-19866, + bsc#1209543) + ------------------------------------------------------------------- Wed Mar 22 17:57:02 UTC 2023 - Bjørn Lie diff --git a/xwayland.spec b/xwayland.spec index af3c531..d6c0964 100644 --- a/xwayland.spec +++ b/xwayland.spec @@ -33,6 +33,7 @@ Group: System/X11/Servers/XF86_4 Source0: %{url}/archive/individual/xserver/%{name}-%{version}.tar.xz Source1: %{url}/archive/individual/xserver/%{name}-%{version}.tar.xz.sig Source2: xwayland.keyring +Patch1209543: U_xserver-composite-Fix-use-after-free-of-the-COW.patch BuildRequires: meson BuildRequires: ninja