[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, gedmurphy at svn.reactos.org 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?rev=70408&r1=70407&r2=70408&view=diff
> ==============================================================================
> --- 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;
> 
>