Messages in this thread | | | Date | Thu, 1 Jun 2023 19:57:13 +0200 | Subject | Re: [PATCH] ASoC: SOF: ipc4-topology: Use size_t for variable passed to kzalloc() | From | Christophe JAILLET <> |
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Le 01/06/2023 à 19:39, Pierre-Louis Bossart a écrit : > > > 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@wanadoo.fr> >> --- >> 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);
My coccinelle script does not handle such cases.
> > not sure how much of an issue this really is though?
I agree that in practice it should be safe as-is, but it can't hurt :). I don't know this code well, but should [2] be part of the call chain, it is obvious that it CAN'T overflow.
I checked for places where such pattern occurs after Dan's comment on another patch. I'll see if I find better candidates.
CJ
[2]: https://elixir.bootlin.com/linux/v6.4-rc1/source/sound/soc/sof/topology.c#L1404
> >> --- >> 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); >
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