xwayland: Fix CVE-2024-21886

The patches are copied from xserver-xorg recipe.
CVE reported for both and patches apply on both.

Upstream-Commit:
bc1fdbe465
& 26769aa71f

(From OE-Core rev: 77487fb0756951e29628f41ff00db12a5f9d7c27)

Signed-off-by: Vijay Anusuri <vanusuri@mvista.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>

meta/recipes-graphics/xwayland/xwayland/CVE-2024-21886-1.patch

@@ -0,0 +1,74 @@
+From bc1fdbe46559dd947674375946bbef54dd0ce36b Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Jos=C3=A9=20Exp=C3=B3sito?= <jexposit@redhat.com>
+Date: Fri, 22 Dec 2023 18:28:31 +0100
+Subject: [PATCH] Xi: do not keep linked list pointer during recursion
+
+The `DisableDevice()` function is called whenever an enabled device
+is disabled and it moves the device from the `inputInfo.devices` linked
+list to the `inputInfo.off_devices` linked list.
+
+However, its link/unlink operation has an issue during the recursive
+call to `DisableDevice()` due to the `prev` pointer pointing to a
+removed device.
+
+This issue leads to a length mismatch between the total number of
+devices and the number of device in the list, leading to a heap
+overflow and, possibly, to local privilege escalation.
+
+Simplify the code that checked whether the device passed to
+`DisableDevice()` was in `inputInfo.devices` or not and find the
+previous device after the recursion.
+
+CVE-2024-21886, ZDI-CAN-22840
+
+This vulnerability was discovered by:
+Jan-Niklas Sohn working with Trend Micro Zero Day Initiative
+
+Upstream-Status: Backport [https://gitlab.freedesktop.org/xorg/xserver/-/commit/bc1fdbe46559dd947674375946bbef54dd0ce36b]
+CVE: CVE-2024-21886
+Signed-off-by: Vijay Anusuri <vanusuri@mvista.com>
+---
+ dix/devices.c | 15 ++++++++++++---
+ 1 file changed, 12 insertions(+), 3 deletions(-)
+
+diff --git a/dix/devices.c b/dix/devices.c
+index dca98c8d1b..389d28a23c 100644
+--- a/dix/devices.c
++++ b/dix/devices.c
+@@ -453,14 +453,20 @@ DisableDevice(DeviceIntPtr dev, BOOL sendevent)
+ {
+     DeviceIntPtr *prev, other;
+     BOOL enabled;
++    BOOL dev_in_devices_list = FALSE;
+     int flags[MAXDEVICES] = { 0 };
+ 
+     if (!dev->enabled)
+         return TRUE;
+ 
+-    for (prev = &inputInfo.devices;
+-         *prev && (*prev != dev); prev = &(*prev)->next);
+-    if (*prev != dev)
++    for (other = inputInfo.devices; other; other = other->next) {
++        if (other == dev) {
++            dev_in_devices_list = TRUE;
++            break;
++        }
++    }
++
++    if (!dev_in_devices_list)
+         return FALSE;
+ 
+     TouchEndPhysicallyActiveTouches(dev);
+@@ -511,6 +517,9 @@ DisableDevice(DeviceIntPtr dev, BOOL sendevent)
+     LeaveWindow(dev);
+     SetFocusOut(dev);
+ 
++    for (prev = &inputInfo.devices;
++         *prev && (*prev != dev); prev = &(*prev)->next);
++
+     *prev = dev->next;
+     dev->next = inputInfo.off_devices;
+     inputInfo.off_devices = dev;
+-- 
+GitLab
+

meta/recipes-graphics/xwayland/xwayland/CVE-2024-21886-2.patch

@@ -0,0 +1,57 @@
+From 26769aa71fcbe0a8403b7fb13b7c9010cc07c3a8 Mon Sep 17 00:00:00 2001
+From: Peter Hutterer <peter.hutterer@who-t.net>
+Date: Fri, 5 Jan 2024 09:40:27 +1000
+Subject: [PATCH] dix: when disabling a master, float disabled slaved devices
+ too
+
+Disabling a master device floats all slave devices but we didn't do this
+to already-disabled slave devices. As a result those devices kept their
+reference to the master device resulting in access to already freed
+memory if the master device was removed before the corresponding slave
+device.
+
+And to match this behavior, also forcibly reset that pointer during
+CloseDownDevices().
+
+Related to CVE-2024-21886, ZDI-CAN-22840
+
+Upstream-Status: Backport [https://gitlab.freedesktop.org/xorg/xserver/-/commit/26769aa71fcbe0a8403b7fb13b7c9010cc07c3a8]
+CVE: CVE-2024-21886
+Signed-off-by: Vijay Anusuri <vanusuri@mvista.com>
+---
+ dix/devices.c | 12 ++++++++++++
+ 1 file changed, 12 insertions(+)
+
+diff --git a/dix/devices.c b/dix/devices.c
+index 389d28a23c..84a6406d13 100644
+--- a/dix/devices.c
++++ b/dix/devices.c
+@@ -483,6 +483,13 @@ DisableDevice(DeviceIntPtr dev, BOOL sendevent)
+                 flags[other->id] |= XISlaveDetached;
+             }
+         }
++
++        for (other = inputInfo.off_devices; other; other = other->next) {
++            if (!IsMaster(other) && GetMaster(other, MASTER_ATTACHED) == dev) {
++                AttachDevice(NULL, other, NULL);
++                flags[other->id] |= XISlaveDetached;
++            }
++        }
+     }
+     else {
+         for (other = inputInfo.devices; other; other = other->next) {
+@@ -1088,6 +1095,11 @@ CloseDownDevices(void)
+             dev->master = NULL;
+     }
+ 
++    for (dev = inputInfo.off_devices; dev; dev = dev->next) {
++        if (!IsMaster(dev) && !IsFloating(dev))
++            dev->master = NULL;
++    }
++
+     CloseDeviceList(&inputInfo.devices);
+     CloseDeviceList(&inputInfo.off_devices);
+ 
+-- 
+GitLab
+

meta/recipes-graphics/xwayland/xwayland_22.1.8.bb

@@ -22,6 +22,8 @@ SRC_URI = "https://www.x.org/archive/individual/xserver/xwayland-${PV}.tar.xz \
            file://CVE-2024-0229-3.patch \
            file://CVE-2024-0229-4.patch \
            file://CVE-2024-21885.patch \
+           file://CVE-2024-21886-1.patch \
+           file://CVE-2024-21886-2.patch \
 "
 SRC_URI[sha256sum] = "d11eeee73290b88ea8da42a7d9350dedfaba856ce4ae44e58c045ad9ecaa2f73"