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/xorg-x11-server.changes b/xorg-x11-server.changes index ce32787..257c1b1 100644 --- a/xorg-x11-server.changes +++ b/xorg-x11-server.changes @@ -1,3 +1,10 @@ +------------------------------------------------------------------- +Wed Mar 22 13:48:21 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) + ------------------------------------------------------------------- Tue Feb 7 14:35:33 UTC 2023 - Stefan Dirsch diff --git a/xorg-x11-server.spec b/xorg-x11-server.spec index f5ab1ec..6ae6e7a 100644 --- a/xorg-x11-server.spec +++ b/xorg-x11-server.spec @@ -242,6 +242,8 @@ Patch1940: U_xephyr-Don-t-check-for-SeatId-anymore.patch Patch1960: u_sync-pci-ids-with-Mesa.patch +Patch1209543: U_xserver-composite-Fix-use-after-free-of-the-COW.patch + %description This package contains the X.Org Server. @@ -400,6 +402,8 @@ sh %{SOURCE92} --verify . %{SOURCE91} %patch1940 -p1 %patch1960 -p1 +%patch1209543 -p1 + %build # We have some -z now related errors during X default startup (boo#1197994): # - when loading modesetting: gbm_bo_get_plane_count