linux-kernel - Re: [PATCH v6 2/7] fpga: sec-mgr: enable secure updates

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Message-ID: <9dd75daf-eb73-4008-ca65-6f7ea3923e35@silicom.dk>
Date:   Thu, 26 Nov 2020 15:02:49 +0100
From:   Martin Hundebøll <mhu@...icom.dk>
To:     Russ Weight <russell.h.weight@...el.com>, mdf@...nel.org,
        linux-fpga@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     trix@...hat.com, lgoncalv@...hat.com, yilun.xu@...el.com,
        hao.wu@...el.com, matthew.gerlach@...el.com
Subject: Re: [PATCH v6 2/7] fpga: sec-mgr: enable secure updates

Hi Russ,

I found another thing while testing this...

On 06/11/2020 02.09, Russ Weight wrote:

<snip>

> +static ssize_t filename_store(struct device *dev, struct device_attribute *attr,
> +			      const char *buf, size_t count)
> +{
> +	struct fpga_sec_mgr *smgr = to_sec_mgr(dev);
> +	int ret = count;
> +
> +	if (count == 0 || count >= PATH_MAX)
> +		return -EINVAL;
> +
> +	mutex_lock(&smgr->lock);
> +	if (smgr->driver_unload || smgr->progress != FPGA_SEC_PROG_IDLE) {
> +		ret = -EBUSY;
> +		goto unlock_exit;
> +	}
> +
> +	smgr->filename = kstrndup(buf, count - 1, GFP_KERNEL);

The `count - 1` is meant to remove a trailing newline, but opae-sdk 
writes the filename without newline, so better do it conditionally...

> +	if (!smgr->filename) {
> +		ret = -ENOMEM;
> +		goto unlock_exit;
> +	}
> +
> +	smgr->err_code = FPGA_SEC_ERR_NONE;
> +	smgr->progress = FPGA_SEC_PROG_READING;
> +	reinit_completion(&smgr->update_done);
> +	schedule_work(&smgr->work);
> +
> +unlock_exit:
> +	mutex_unlock(&smgr->lock);
> +	return ret;
> +}
> +static DEVICE_ATTR_WO(filename);
> +
> +static struct attribute *sec_mgr_update_attrs[] = {
> +	&dev_attr_filename.attr,
> +	NULL,
> +};

Thanks,
Martin