Re: [ros-dev] [ros-diffs] [aandrejevic] 68607: [FASTFAT] Irp->UserBuffer being NULL doesn't indicate any error. It could be that the caller really wants the result stored at address NULL (which can be valid, and is valid by...

[Pierre Schweitzer]

This patch, as it, is really dangerous. MS allows null pointer in its
Read/Write routines, but they are wrapped inside a SEH block, to prevent
nasty things to happen in case of a null pointer dereference.

Here we don't, meaning that a null pointer here will cause major damages.

Furthermore, your commit regressed ntdll:file:
https://reactos.org/sites/all/modules/reactos/testman/compare.php?ids=40042…

Regards,

On 08/07/2015 05:30 AM, aandrejevic(a)svn.reactos.org wrote:
>   Author: aandrejevic
>  Date: Fri Aug  7 03:30:05 2015
>  New Revision: 68607
>  
>  URL: http://svn.reactos.org/svn/reactos?rev=68607&view=rev
>  Log:
>  [FASTFAT]
>  Irp->UserBuffer being NULL doesn't indicate any error. It could be that the
>  caller really wants the result stored at address NULL (which can be valid,
>  and is valid by default for programs like NTVDM).
>  
>  
>  Modified:
>      trunk/reactos/drivers/filesystems/fastfat/rw.c
>  
>  Modified: trunk/reactos/drivers/filesystems/fastfat/rw.c
>  URL:
> http://svn.reactos.org/svn/reactos/trunk/reactos/drivers/filesystems/fastfa…
>  ==============================================================================
>  --- trunk/reactos/drivers/filesystems/fastfat/rw.c	[iso-8859-1] (original)
>  +++ trunk/reactos/drivers/filesystems/fastfat/rw.c	[iso-8859-1] Fri Aug  7 03:30:05 2015
>  @@ -656,7 +656,7 @@
>       }
>   
>       Buffer = VfatGetUserBuffer(IrpContext->Irp,
> BooleanFlagOn(IrpContext->Irp->Flags, IRP_PAGING_IO));
>  -    if (!Buffer)
>  +    if (!Buffer && IrpContext->Irp->MdlAddress)
>       {
>           Status = STATUS_INVALID_USER_BUFFER;
>           goto ByeBye;
>  @@ -927,7 +927,7 @@
>       OldFileSize = Fcb->RFCB.FileSize;
>   
>       Buffer = VfatGetUserBuffer(IrpContext->Irp,
> BooleanFlagOn(IrpContext->Irp->Flags, IRP_PAGING_IO));
>  -    if (!Buffer)
>  +    if (!Buffer && IrpContext->Irp->MdlAddress)
>       {
>           Status = STATUS_INVALID_USER_BUFFER;
>           goto ByeBye;
>  
>   

-- 
Pierre Schweitzer <pierre(a)reactos.org>
System & Network Administrator
Senior Kernel Developer
ReactOS Deutschland e.V.