[PATCH] ASoC: max98390: Fix potential crash during param fw loading

[Mark Brown]

On Wed, Jun 03, 2020 at 08:18:19PM +0900, Steve Lee wrote:

> +	param_start_addr = (dsm_param[0] & 0xff) | (dsm_param[1] & 0xff) << 8;
> +	param_size = (dsm_param[2] & 0xff) | (dsm_param[3] & 0xff) << 8;
> +	if (param_size > MAX98390_DSM_PARAM_MAX_SIZE ||
> +		param_start_addr < DSM_STBASS_HPF_B0_BYTE0) {
> +		dev_err(component->dev,
> +			"param fw is invalid.\n");
> +		goto err_alloc;
> +	}

This is now reading the size out of the header of the file which is good
but it should also validate that the file is big enough to have this
much data in it, otherwise it's possible to read beyond the end of the
firmware file (eg, if it got truncated somehow).  Previously the code
used the size of the file read from disk so that wasn't an issue.
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