diff options
Diffstat (limited to 'patches/source/xorg-server/patch/xorg-server/CVE-2023-5380.patch')
-rw-r--r-- | patches/source/xorg-server/patch/xorg-server/CVE-2023-5380.patch | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/patches/source/xorg-server/patch/xorg-server/CVE-2023-5380.patch b/patches/source/xorg-server/patch/xorg-server/CVE-2023-5380.patch new file mode 100644 index 000000000..a358076dc --- /dev/null +++ b/patches/source/xorg-server/patch/xorg-server/CVE-2023-5380.patch @@ -0,0 +1,99 @@ +From 564ccf2ce9616620456102727acb8b0256b7bbd7 Mon Sep 17 00:00:00 2001 +From: Peter Hutterer <peter.hutterer@who-t.net> +Date: Thu, 5 Oct 2023 12:19:45 +1000 +Subject: [PATCH] mi: reset the PointerWindows reference on screen switch + +PointerWindows[] keeps a reference to the last window our sprite +entered - changes are usually handled by CheckMotion(). + +If we switch between screens via XWarpPointer our +dev->spriteInfo->sprite->win is set to the new screen's root window. +If there's another window at the cursor location CheckMotion() will +trigger the right enter/leave events later. If there is not, it skips +that process and we never trigger LeaveWindow() - PointerWindows[] for +the device still refers to the previous window. + +If that window is destroyed we have a dangling reference that will +eventually cause a use-after-free bug when checking the window hierarchy +later. + +To trigger this, we require: +- two protocol screens +- XWarpPointer to the other screen's root window +- XDestroyWindow before entering any other window + +This is a niche bug so we hack around it by making sure we reset the +PointerWindows[] entry so we cannot have a dangling pointer. This +doesn't handle Enter/Leave events correctly but the previous code didn't +either. + +CVE-2023-5380, ZDI-CAN-21608 + +This vulnerability was discovered by: +Sri working with Trend Micro Zero Day Initiative + +Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net> +Reviewed-by: Adam Jackson <ajax@redhat.com> +--- + dix/enterleave.h | 2 -- + include/eventstr.h | 3 +++ + mi/mipointer.c | 17 +++++++++++++++-- + 3 files changed, 18 insertions(+), 4 deletions(-) + +diff --git a/dix/enterleave.h b/dix/enterleave.h +index 4b833d8a3b..e8af924c68 100644 +--- a/dix/enterleave.h ++++ b/dix/enterleave.h +@@ -58,8 +58,6 @@ extern void DeviceFocusEvent(DeviceIntPtr dev, + + extern void EnterWindow(DeviceIntPtr dev, WindowPtr win, int mode); + +-extern void LeaveWindow(DeviceIntPtr dev); +- + extern void CoreFocusEvent(DeviceIntPtr kbd, + int type, int mode, int detail, WindowPtr pWin); + +diff --git a/include/eventstr.h b/include/eventstr.h +index 93308f9b24..a9926eaeef 100644 +--- a/include/eventstr.h ++++ b/include/eventstr.h +@@ -335,4 +335,7 @@ union _InternalEvent { + GestureEvent gesture_event; + }; + ++extern void ++LeaveWindow(DeviceIntPtr dev); ++ + #endif +diff --git a/mi/mipointer.c b/mi/mipointer.c +index a638f25d4a..8cf0035140 100644 +--- a/mi/mipointer.c ++++ b/mi/mipointer.c +@@ -397,8 +397,21 @@ miPointerWarpCursor(DeviceIntPtr pDev, ScreenPtr pScreen, int x, int y) + #ifdef PANORAMIX + && noPanoramiXExtension + #endif +- ) +- UpdateSpriteForScreen(pDev, pScreen); ++ ) { ++ DeviceIntPtr master = GetMaster(pDev, MASTER_POINTER); ++ /* Hack for CVE-2023-5380: if we're moving ++ * screens PointerWindows[] keeps referring to the ++ * old window. If that gets destroyed we have a UAF ++ * bug later. Only happens when jumping from a window ++ * to the root window on the other screen. ++ * Enter/Leave events are incorrect for that case but ++ * too niche to fix. ++ */ ++ LeaveWindow(pDev); ++ if (master) ++ LeaveWindow(master); ++ UpdateSpriteForScreen(pDev, pScreen); ++ } + } + + /** +-- +GitLab + +B |