Re: [PATCH v2] usb: gadget: functioni: Fix a oob problem in rndis

[Greg KH <gregkh@linuxfoundation.org>]

On Thu, Jul 10, 2025 at 11:16:41AM +0200, Greg KH wrote:
> On Thu, Jul 10, 2025 at 04:49:22PM +0800, jackysliu wrote:
> > From: Siyang Liu <1972843537@qq.com>
> > 
> > An out-of-bounds memory access vulnerability exists in the RNDIS
> > (Remote Network Driver Interface Specification) implementation.
> > The vulnerability stems from insufficient boundary validation when
> > processing SET requests with user-controlled InformationBufferOffset
> > and InformationBufferLength parameters.
> > 
> > Fix on commit id:
> > commit 5f60d5f6bbc1 ("move asm/unaligned.h to linux/unaligned.h")
> > 
> > The vulnerability can be fixed by adding addtional boundary checks
> > 
> > Signed-off-by: Siyang Liu <1972843537@qq.com>
> > ---
> >  drivers/usb/gadget/function/rndis.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/usb/gadget/function/rndis.c b/drivers/usb/gadget/function/rndis.c
> > index afd75d72412c..cc522fb4c06c 100644
> > --- a/drivers/usb/gadget/function/rndis.c
> > +++ b/drivers/usb/gadget/function/rndis.c
> > @@ -641,7 +641,8 @@ static int rndis_set_response(struct rndis_params *params,
> >  	BufOffset = le32_to_cpu(buf->InformationBufferOffset);
> >  	if ((BufLength > RNDIS_MAX_TOTAL_SIZE) ||
> >  	    (BufOffset > RNDIS_MAX_TOTAL_SIZE) ||
> > -	    (BufOffset + 8 >= RNDIS_MAX_TOTAL_SIZE))
> > +	    (BufOffset + 8 >= RNDIS_MAX_TOTAL_SIZE) ||
> > +		(BufOffset + BufLength+8 > RNDIS_MAX_TOTAL_SIZE))
> 
> Odd, this should be "BufLength + 8" as checkpatch says:
> 
> CHECK: spaces preferred around that '+' (ctx:VxV)
> #121: FILE: drivers/usb/gadget/function/rndis.c:645:
> +		(BufOffset + BufLength+8 > RNDIS_MAX_TOTAL_SIZE))
>  		                     ^

And the indentation needs to be fixed up too.  I'll do that...

How was this tested?

thanks,

greg k-h