Re: [PATCH next v2] nvdimm: Prevent integer overflow in ramdax_get_config_data()

[Mike Rapoport]

On Wed, Nov 26, 2025 at 03:11:53PM +0300, Dan Carpenter wrote:
> The "cmd->in_offset" variable comes from the user via the __nd_ioctl()
> function.  The problem is that the "cmd->in_offset + cmd->in_length"
> addition could have an integer wrapping issue if cmd->in_offset is close
> to UINT_MAX .  Both "cmd->in_offset" and "cmd->in_length" are u32
> variables.
> 
> Fixes: 43bc0aa19a21 ("nvdimm: allow exposing RAM carveouts as NVDIMM DIMM devices")
> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

Acked-by: Mike Rapoport (Microsoft) <rppt@xxxxxxxxxx>

> ---
> v2: Ira Weiny pointed out that ramdax_set_config_data() needs to be
>     fixed as well.
> 
>  drivers/nvdimm/ramdax.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/nvdimm/ramdax.c b/drivers/nvdimm/ramdax.c
> index 63cf05791829..954cb7919807 100644
> --- a/drivers/nvdimm/ramdax.c
> +++ b/drivers/nvdimm/ramdax.c
> @@ -143,7 +143,7 @@ static int ramdax_get_config_data(struct nvdimm *nvdimm, int buf_len,
>  		return -EINVAL;
>  	if (struct_size(cmd, out_buf, cmd->in_length) > buf_len)
>  		return -EINVAL;
> -	if (cmd->in_offset + cmd->in_length > LABEL_AREA_SIZE)
> +	if (size_add(cmd->in_offset, cmd->in_length) > LABEL_AREA_SIZE)
>  		return -EINVAL;
>  
>  	memcpy(cmd->out_buf, dimm->label_area + cmd->in_offset, cmd->in_length);
> @@ -160,7 +160,7 @@ static int ramdax_set_config_data(struct nvdimm *nvdimm, int buf_len,
>  		return -EINVAL;
>  	if (struct_size(cmd, in_buf, cmd->in_length) > buf_len)
>  		return -EINVAL;
> -	if (cmd->in_offset + cmd->in_length > LABEL_AREA_SIZE)
> +	if (size_add(cmd->in_offset, cmd->in_length) > LABEL_AREA_SIZE)
>  		return -EINVAL;
>  
>  	memcpy(dimm->label_area + cmd->in_offset, cmd->in_buf, cmd->in_length);
> -- 
> 2.51.0
> 

-- 
Sincerely yours,
Mike.