Re: [ros-dev] [ros-diffs] [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

[Thomas Faber]

Uhm... raising the IRQL is not a synchronization mechanism. Should
there be a spinlock involved?

On 2015-12-23 12:26, [e-mail] wrote:
> 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;