[gedmurphy] 70408: [NTOSKRNL] - Raise the IRQL when enumerating device lists so it doesn't get edited mid-listing - Don't hardcode the pointer size when checking the buffer size

Author: gedmurphy
Date: Wed Dec 23 11:26:28 2015
New Revision: 70408

URL: http://svn.reactos.org/svn/reactos?rev=70408&view=rev
Log:
[NTOSKRNL]
- Raise the IRQL when enumerating device lists so it doesn't get edited mid-listing
- Don't hardcode the pointer size when checking the buffer size

Modified:
    trunk/reactos/ntoskrnl/io/iomgr/device.c

Modified: trunk/reactos/ntoskrnl/io/iomgr/device.c
URL: http://svn.reactos.org/svn/reactos/trunk/reactos/ntoskrnl/io/iomgr/device.c?...
==============================================================================
--- trunk/reactos/ntoskrnl/io/iomgr/device.c	[iso-8859-1] (original)
+++ trunk/reactos/ntoskrnl/io/iomgr/device.c	[iso-8859-1] Wed Dec 23 11:26:28 2015
@@ -1088,6 +1088,10 @@
 {
     ULONG ActualDevices = 1;
     PDEVICE_OBJECT CurrentDevice = DriverObject->DeviceObject;
+    KIRQL OldIrql;
+
+    /* Raise to dispatch level */
+    KeRaiseIrql(DISPATCH_LEVEL, &OldIrql);

/* Find out how many devices we'll enumerate */
     while ((CurrentDevice = CurrentDevice->NextDevice)) ActualDevices++;
@@ -1099,13 +1103,14 @@
     *ActualNumberDeviceObjects = ActualDevices;

/* Check if we can support so many */
-    if ((ActualDevices * 4) > DeviceObjectListSize)
+    if ((ActualDevices * sizeof(PDEVICE_OBJECT)) > DeviceObjectListSize)
     {
         /* Fail because the buffer was too small */
+        KeLowerIrql(OldIrql);
         return STATUS_BUFFER_TOO_SMALL;
     }

-    /* Check if the caller only wanted the size */
+    /* Check if the caller wanted the device list */
     if (DeviceObjectList)
     {
         /* Loop through all the devices */
@@ -1123,6 +1128,9 @@
             DeviceObjectList++;
         }
     }
+
+    /* Return back to previous IRQL */
+    KeLowerIrql(OldIrql);

/* Return the status */
     return STATUS_SUCCESS;