Re: [Intel-wired-lan] [PATCH iwl-next v2] i40e: fix MMIO write access to an invalid page in i40e_clear_hw

[Simon Horman <horms@kernel.org>]

On Tue, Mar 11, 2025 at 02:16:02PM +0900, Kyungwook Boo wrote:
> When the device sends a specific input, an integer underflow can occur, leading
> to MMIO write access to an invalid page.
> 
> Prevent the integer underflow by changing the type of related variables.
> 
> Signed-off-by: Kyungwook Boo <bookyungwook@gmail.com>
> Link: https://lore.kernel.org/lkml/ffc91764-1142-4ba2-91b6-8c773f6f7095@gmail.com/T/
> ---
> Changes in v2:
> - Formatting properly
> - Fix variable shadowing
> - Link to v1: https://lore.kernel.org/netdev/55acc5dc-8d5a-45bc-a59c-9304071e4579@gmail.com/
> ---
>  drivers/net/ethernet/intel/i40e/i40e_common.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/i40e/i40e_common.c b/drivers/net/ethernet/intel/i40e/i40e_common.c
> index 370b4bddee44..b11c35e307ca 100644
> --- a/drivers/net/ethernet/intel/i40e/i40e_common.c
> +++ b/drivers/net/ethernet/intel/i40e/i40e_common.c
> @@ -817,10 +817,11 @@ int i40e_pf_reset(struct i40e_hw *hw)
>  void i40e_clear_hw(struct i40e_hw *hw)
>  {
>  	u32 num_queues, base_queue;
> -	u32 num_pf_int;
> -	u32 num_vf_int;
> +	s32 num_pf_int;
> +	s32 num_vf_int;
>  	u32 num_vfs;
> -	u32 i, j;
> +	s32 i;
> +	u32 j;
>  	u32 val;
>  	u32 eol = 0x7ff;
>  
> ---
> base-commit: 4d872d51bc9d7b899c1f61534e3dbde72613f627

I see that this addresses the problem at the first link above.
And I'd happy to see it accepted as-is.

Reviewed-by: Simon Horman <horms@kernel.org>

But, as an aside, wouldn't it be more appropriate to use generic
types like int and unsigned int for most of the above variables?
Perhaps this could be addressed by a follow-up. Or perhaps that
would just be churn, IDK.