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Date:   Wed, 27 Jul 2022 15:14:10 +0200
From:   Greg KH <gregkh@linuxfoundation.org>
To:     Jiho Chu <jiho.chu@samsung.com>
Cc:     arnd@arndb.de, linux-kernel@vger.kernel.org,
        yelini.jeong@samsung.com, myungjoo.ham@samsung.com
Subject: Re: [PATCH 3/9] trinity: Add load/unload IDU files
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References: <20220725065308.2457024-1-jiho.chu@samsung.com>
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 <20220725065308.2457024-4-jiho.chu@samsung.com>
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On Mon, Jul 25, 2022 at 03:53:02PM +0900, Jiho Chu wrote:
> +static int triv2_idu_load_file(struct trinity_driver *drv, const char *dirpath,
> +			       const char *file_name,
> +			       struct trinity_resv_mem *sector)
> +{
> +	struct device *dev = drv_to_dev_ptr(drv);
> +	struct trinity_resv_mem mem;
> +	char filepath[NAME_MAX];
> +	struct kstat *stat;
> +	struct file *filp;
> +	loff_t pos = 0;
> +	size_t size;
> +	int ret;
> +
> +	dev = drv_to_dev_ptr(drv);
> +	stat = vmalloc(sizeof(*stat));
> +	if (stat == NULL)
> +		return -ENOMEM;
> +
> +	/* if dirpath is null, use the default path */
> +	if (dirpath)
> +		snprintf(filepath, NAME_MAX, "%s/%s", dirpath, file_name);
> +	else
> +		snprintf(filepath, NAME_MAX, TRIV2_IDU_DIRPATH_FMT "/%s",
> +			 utsname()->release, file_name);
> +
> +	filp = filp_open(filepath, O_RDONLY, 0400);

That is cute.  And totally not ok.

Please never do this, that is not how to properly load a firmware blob
in the kernel.  This is racy and broken and probably a huge security
hole.

Heck, I wrote an article about this very topic, way back in 2005, with
the title of, "Things you should never do in the kernel" and can be seen
here:
	https://www.linuxjournal.com/article/8110

This should not be news to anyone, again, never do this.

thanks,

greg k-h