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

[Greg KH <gregkh@linuxfoundation.org>]

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))
 		                     ^

I'll go fix this up by hand, but be more careful in the future...

thanks,

greg k-h