Multiple issues have been found in the X server and Xwayland

implementations:

1) CVE-2023-6816 can be triggered by passing an invalid array index to
DeviceFocusEvent or ProcXIQueryPointer.

2) CVE-2024-0229 can be triggered if a device has both a button and a
key class and zero buttons.

3) CVE-2024-21885 can be triggered if a device with a given ID was
removed and a new device with the same ID added both in the same
operation.

4) CVE-2024-21886 can be triggered by disabling a master device with
disabled slave devices.

5) CVE-2024-0409 can be triggered by enabling SELinux
xserver_object_manager and running a client.

6) CVE-2024-0408 can be triggered by enabling SELinux
xserver_object_manager and creating a GLX PBuffer.

3 files changed, 26 insertions, 9 deletions

diff --git a/xserver/Xi/exevents.c b/xserver/Xi/exevents.c
index 54ea11a93..e16171468 100644
--- a/xserver/Xi/exevents.c
+++ b/xserver/Xi/exevents.c
@@ -605,6 +605,7 @@ DeepCopyPointerClasses(DeviceIntPtr from, DeviceIntPtr to)
                 to->button = calloc(1, sizeof(ButtonClassRec));
                 if (!to->button)
                     FatalError("[Xi] no memory for class shift.\n");
+                to->button->numButtons = from->button->numButtons;
             }
             else
                 classes->button = NULL;
diff --git a/xserver/Xi/xichangehierarchy.c b/xserver/Xi/xichangehierarchy.c
index 504defe56..72d00451e 100644
--- a/xserver/Xi/xichangehierarchy.c
+++ b/xserver/Xi/xichangehierarchy.c
@@ -270,7 +270,7 @@ remove_master(ClientPtr client, xXIRemoveMasterInfo * r, int flags[MAXDEVICES])
         if (rc != Success)
             goto unwind;
 
-        if (!IsMaster(newptr)) {
+        if (!IsMaster(newptr) || !IsPointerDevice(newptr)) {
             client->errorValue = r->return_pointer;
             rc = BadDevice;
             goto unwind;
@@ -281,7 +281,7 @@ remove_master(ClientPtr client, xXIRemoveMasterInfo * r, int flags[MAXDEVICES])
         if (rc != Success)
             goto unwind;
 
-        if (!IsMaster(newkeybd)) {
+        if (!IsMaster(newkeybd) || !IsKeyboardDevice(newkeybd)) {
             client->errorValue = r->return_keyboard;
             rc = BadDevice;
             goto unwind;
@@ -416,6 +416,11 @@ ProcXIChangeHierarchy(ClientPtr client)
     size_t len;			/* length of data remaining in request */
     int rc = Success;
     int flags[MAXDEVICES] = { 0 };
+    enum {
+        NO_CHANGE,
+        FLUSH,
+        CHANGED,
+    } changes = NO_CHANGE;
 
     REQUEST(xXIChangeHierarchyReq);
     REQUEST_AT_LEAST_SIZE(xXIChangeHierarchyReq);
@@ -465,8 +470,9 @@ ProcXIChangeHierarchy(ClientPtr client)
             rc = add_master(client, c, flags);
             if (rc != Success)
                 goto unwind;
-        }
+            changes = FLUSH;
             break;
+        }
         case XIRemoveMaster:
         {
             xXIRemoveMasterInfo *r = (xXIRemoveMasterInfo *) any;
@@ -475,8 +481,9 @@ ProcXIChangeHierarchy(ClientPtr client)
             rc = remove_master(client, r, flags);
             if (rc != Success)
                 goto unwind;
-        }
+            changes = FLUSH;
             break;
+        }
         case XIDetachSlave:
         {
             xXIDetachSlaveInfo *c = (xXIDetachSlaveInfo *) any;
@@ -485,8 +492,9 @@ ProcXIChangeHierarchy(ClientPtr client)
             rc = detach_slave(client, c, flags);
             if (rc != Success)
                 goto unwind;
-        }
+            changes = CHANGED;
             break;
+        }
         case XIAttachSlave:
         {
             xXIAttachSlaveInfo *c = (xXIAttachSlaveInfo *) any;
@@ -495,16 +503,25 @@ ProcXIChangeHierarchy(ClientPtr client)
             rc = attach_slave(client, c, flags);
             if (rc != Success)
                 goto unwind;
+            changes = CHANGED;
+            break;
         }
+        default:
             break;
         }
 
+        if (changes == FLUSH) {
+            XISendDeviceHierarchyEvent(flags);
+            memset(flags, 0, sizeof(flags));
+            changes = NO_CHANGE;
+        }
+
         len -= any->length * 4;
         any = (xXIAnyHierarchyChangeInfo *) ((char *) any + any->length * 4);
     }
 
  unwind:
-
-    XISendDeviceHierarchyEvent(flags);
+    if (changes != NO_CHANGE)
+        XISendDeviceHierarchyEvent(flags);
     return rc;
 }
diff --git a/xserver/Xi/xiquerypointer.c b/xserver/Xi/xiquerypointer.c
index 5b77b1a44..2b05ac5f3 100644
--- a/xserver/Xi/xiquerypointer.c
+++ b/xserver/Xi/xiquerypointer.c
@@ -149,8 +149,7 @@ ProcXIQueryPointer(ClientPtr client)
     if (pDev->button) {
         int i;
 
-        rep.buttons_len =
-            bytes_to_int32(bits_to_bytes(pDev->button->numButtons));
+        rep.buttons_len = bytes_to_int32(bits_to_bytes(256)); /* button map up to 255 */
         rep.length += rep.buttons_len;
         buttons = calloc(rep.buttons_len, 4);
         if (!buttons)