Re: [PATCH v2 3/7] test_firmware: add partial read support for request_firmware_into_buf

From: Dan Carpenter <dan.carpenter@oracle.com>
To: Scott Branden <scott.branden@broadcom.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	David Brown <david.brown@linaro.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Shuah Khan <shuah@kernel.org>,
	bjorn.andersson@linaro.org,
	Shuah Khan <skhan@linuxfoundation.org>,
	Arnd Bergmann <arnd@arndb.de>,
	"Rafael J . Wysocki" <rafael@kernel.org>,
	linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	linux-fsdevel@vger.kernel.org,
	BCM Kernel Feedback <bcm-kernel-feedback-list@broadcom.com>,
	Olof Johansson <olof@lixom.net>,
	Andrew Morton <akpm@linux-foundation.org>,
	Colin Ian King <colin.king@canonical.com>,
	Kees Cook <keescook@chromium.org>, Takashi Iwai <tiwai@suse.de>,
	linux-kselftest@vger.kernel.org, Andy Gross <agross@kernel.org>
Subject: Re: [PATCH v2 3/7] test_firmware: add partial read support for request_firmware_into_buf
Date: Thu, 20 Feb 2020 11:42:55 +0300	[thread overview]
Message-ID: <20200220084255.GW7838@kadam> (raw)
In-Reply-To: <20200220004825.23372-4-scott.branden@broadcom.com>

On Wed, Feb 19, 2020 at 04:48:21PM -0800, Scott Branden wrote:
> +static int test_dev_config_update_size_t(const char *buf,
> +					 size_t size,
> +					 size_t *cfg)
> +{
> +	int ret;
> +	long new;
> +
> +	ret = kstrtol(buf, 10, &new);
> +	if (ret)
> +		return ret;
> +
> +	if (new > SIZE_MAX)

This "new" variable is long and SIZE_MAX is ULONG_MAX so the condition
can't be true.

> +		return -EINVAL;
> +
> +	mutex_lock(&test_fw_mutex);
> +	*(size_t *)cfg = new;
> +	mutex_unlock(&test_fw_mutex);
> +
> +	/* Always return full write size even if we didn't consume all */
> +	return size;
> +}
> +
> +static ssize_t test_dev_config_show_size_t(char *buf, int cfg)
> +{
> +	size_t val;
> +
> +	mutex_lock(&test_fw_mutex);
> +	val = cfg;
> +	mutex_unlock(&test_fw_mutex);

Both val and cfg are stack variables so there is no need for locking.
Probably you meant to pass a pointer to cfg?

> +
> +	return snprintf(buf, PAGE_SIZE, "%zu\n", val);
> +}
> +
>  static ssize_t test_dev_config_show_int(char *buf, int cfg)
>  {
>  	int val;

regards,
dan carpenter