From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: linux-fbdev@vger.kernel.org
Subject: Re: [patch] fbdev: fix snprintf() limit in show_bl_curve()
Date: Fri, 21 Aug 2015 09:22:03 +0000 [thread overview]
Message-ID: <1440148923.23472.15.camel@linux.intel.com> (raw)
In-Reply-To: <20150821085302.GE25369@mwanda>
On Fri, 2015-08-21 at 11:53 +0300, Dan Carpenter wrote:
> The limit should be "PAGE_SIZE - len" instead of PAGE_SIZE.
>
Besides that was in the original code, the problem still might happen
when FB_BACKLIGHT_LEVELS is set to 171+ since snprintf() returns
desired length. I suppose you would change this to check len on each
iteration or change to scnprintf() if I get it correct.
> diff --git a/drivers/video/fbdev/core/fbsysfs.c
> b/drivers/video/fbdev/core/fbsysfs.c
> index 60c3f0a..827098d 100644
> --- a/drivers/video/fbdev/core/fbsysfs.c
> +++ b/drivers/video/fbdev/core/fbsysfs.c
> @@ -485,7 +485,7 @@ static ssize_t show_bl_curve(struct device
> *device,
>
> mutex_lock(&fb_info->bl_curve_mutex);
> for (i = 0; i < FB_BACKLIGHT_LEVELS; i += 8)
> - len += snprintf(&buf[len], PAGE_SIZE, "%8ph\n",
> + len += snprintf(&buf[len], PAGE_SIZE - len,
> "%8ph\n",
> fb_info->bl_curve + i);
> mutex_unlock(&fb_info->bl_curve_mutex);
>
--
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy
next prev parent reply other threads:[~2015-08-21 9:22 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-21 8:53 [patch] fbdev: fix snprintf() limit in show_bl_curve() Dan Carpenter
2015-08-21 9:22 ` Andy Shevchenko [this message]
2015-08-21 9:53 ` Dan Carpenter
2015-08-21 11:26 ` Andy Shevchenko
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