Re: [PATCH] ASoC: SOF: ipc4-topology: Use size_t for variable passed to kzalloc()

[Pierre-Louis Bossart]

On 6/1/23 12:30, Christophe JAILLET wrote:
> struct_size() checks for overflow, but assigning its result to just a u32
> may still overflow after a successful check.
> 
> Use a size_t instead in order to be cleaner.
> 
> Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
> ---
> Based on analysis from Dan Carpenter on another patch (see [1]).
> 
> [1]: https://lore.kernel.org/all/00e84595-e2c9-48ea-8737-18da34eaafbf@kili.mountain/

looks like there are similar cases of struct_size -> u32 conversions in
other places:

struct snd_sof_control {
    u32 size;	/* cdata size */

ipc3-topology.c:        scontrol->size = struct_size(cdata, chanv,
scontrol->num_channels);
ipc3-topology.c:        scontrol->size = struct_size(cdata, chanv,
scontrol->num_channels);
ipc4-topology.c:        scontrol->size = struct_size(control_data,
chanv, scontrol->num_channels);

not sure how much of an issue this really is though?

> ---
>  sound/soc/sof/ipc4-topology.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/sound/soc/sof/ipc4-topology.c b/sound/soc/sof/ipc4-topology.c
> index db64e0cb8663..50faa4c88b97 100644
> --- a/sound/soc/sof/ipc4-topology.c
> +++ b/sound/soc/sof/ipc4-topology.c
> @@ -881,7 +881,7 @@ static int sof_ipc4_widget_setup_comp_process(struct snd_sof_widget *swidget)
>  	/* allocate memory for base config extension if needed */
>  	if (process->init_config == SOF_IPC4_MODULE_INIT_CONFIG_TYPE_BASE_CFG_WITH_EXT) {
>  		struct sof_ipc4_base_module_cfg_ext *base_cfg_ext;
> -		u32 ext_size = struct_size(base_cfg_ext, pin_formats,
> +		size_t ext_size = struct_size(base_cfg_ext, pin_formats,
>  						swidget->num_input_pins + swidget->num_output_pins);
>  
>  		base_cfg_ext = kzalloc(ext_size, GFP_KERNEL);