Re: [PATCH v1] dmaengine: idxd: Fix allowing write() from different address spaces

[Dave Jiang <dave.jiang@intel.com>]

On 4/15/25 7:52 PM, Vinicius Costa Gomes wrote:
> Check if the process submitting the descriptor belongs to the same
> address space as the one that opened the file, reject otherwise.
> 
> Fixes: 6827738dc684 ("dmaengine: idxd: add a write() method for applications to submit work")
> Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>

Reviewed-by: Dave Jiang <dave.jiang@intel.com>

> ---
>  drivers/dma/idxd/cdev.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/dma/idxd/cdev.c b/drivers/dma/idxd/cdev.c
> index ff94ee892339..373c622fcddc 100644
> --- a/drivers/dma/idxd/cdev.c
> +++ b/drivers/dma/idxd/cdev.c
> @@ -473,6 +473,9 @@ static ssize_t idxd_cdev_write(struct file *filp, const char __user *buf, size_t
>  	ssize_t written = 0;
>  	int i;
>  
> +	if (current->mm != ctx->mm)
> +		return -EPERM;
> +
>  	for (i = 0; i < len/sizeof(struct dsa_hw_desc); i++) {
>  		int rc = idxd_submit_user_descriptor(ctx, udesc + i);
>