[bug report] ASoC: topology: fix endianness issues

[Dan Carpenter]

[ This bug is way older than your patch but you might know the answer.
  -dan ]

Hello Pierre-Louis Bossart,

The patch 5aebe7c7f9c2: "ASoC: topology: fix endianness issues" from
Apr 4, 2019, leads to the following static checker warning:

	sound/soc/soc-topology.c:903 soc_tplg_denum_create_values()
	warn: potential pointer math issue ('se->dobj.control.dvalues' is a 64 bit pointer)

sound/soc/soc-topology.c
   887  static int soc_tplg_denum_create_values(struct soc_tplg *tplg, struct soc_enum *se,
   888                                          struct snd_soc_tplg_enum_control *ec)
   889  {
   890          int i;
   891  
   892          if (le32_to_cpu(ec->items) > sizeof(*ec->values))

The warning is from this line where Smatch starts to think that
"ec->items" is the number of bytes, but later in the function we treat
it was the number of elements.

I do think probably this should be if:

		if (le32_to_cpu(ec->items) > ARRAY_SIZE(ec->values))
			return -EINVAL;

The ec->values[] is an array of u32:

	__le32 values[SND_SOC_TPLG_NUM_TEXTS * SNDRV_CTL_ELEM_ID_NAME_MAXLEN / 4];

so this code will return -EINVAL for anything larger than 4.  Changing
it to ARRAY_SIZE() would raise the limit to 176.

   893                  return -EINVAL;
   894  
   895          se->dobj.control.dvalues = devm_kzalloc(tplg->dev, le32_to_cpu(ec->items) *
   896                                             sizeof(u32),
   897                                             GFP_KERNEL);
   898          if (!se->dobj.control.dvalues)
   899                  return -ENOMEM;
   900  
   901          /* convert from little-endian */
   902          for (i = 0; i < le32_to_cpu(ec->items); i++) {
   903                  se->dobj.control.dvalues[i] = le32_to_cpu(ec->values[i]);
   904          }
   905  
   906          return 0;
   907  }

regards,
dan carpenter