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From: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Arnd Bergmann <arnd@arndb.de>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Andrea Righi <righi.andrea@gmail.com>,
	Daniel Vetter <daniel.vetter@ffwll.ch>,
	Sam Ravnborg <sam@ravnborg.org>,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Daniel Thompson <daniel.thompson@linaro.org>,
	Peter Rosin <peda@axentia.se>,
	Jani Nikula <jani.nikula@intel.com>,
	Gerd Hoffmann <kraxel@redhat.com>,
	dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org,
	linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: Re: [PATCH v2] fbdev: potential information leak in do_fb_ioctl()
Date: Wed, 15 Jan 2020 15:31:29 +0100	[thread overview]
Message-ID: <ac5585a5-1670-92d2-c019-f349df123f47@samsung.com> (raw)
In-Reply-To: <20200113100132.ixpaymordi24n3av@kili.mountain>


On 1/13/20 12:08 PM, Dan Carpenter wrote:
> The "fix" struct has a 2 byte hole after ->ywrapstep and the
> "fix = info->fix;" assignment doesn't necessarily clear it.  It depends
> on the compiler.  The solution is just to replace the assignment with an
> memcpy().
> 
> Fixes: 1f5e31d7e55a ("fbmem: don't call copy_from/to_user() with mutex held")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

Patch queued for v5.6, thanks.

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics

> ---
> v2:  Use memcpy()
> 
>  drivers/video/fbdev/core/fbmem.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
> index d04554959ea7..bb8d8dbc0461 100644
> --- a/drivers/video/fbdev/core/fbmem.c
> +++ b/drivers/video/fbdev/core/fbmem.c
> @@ -1115,7 +1115,7 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
>  		break;
>  	case FBIOGET_FSCREENINFO:
>  		lock_fb_info(info);
> -		fix = info->fix;
> +		memcpy(&fix, &info->fix, sizeof(fix));
>  		if (info->flags & FBINFO_HIDE_SMEM_START)
>  			fix.smem_start = 0;
>  		unlock_fb_info(info);
> 

  reply	other threads:[~2020-01-15 14:31 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-29 18:23 [PATCH] fbdev: potential information leak in do_fb_ioctl() Dan Carpenter
2019-10-29 18:35 ` Joe Perches
2019-10-29 19:02 ` Eric W. Biederman
2019-10-30  7:43   ` Andrea Righi
2019-10-30 19:26     ` Eric W. Biederman
2019-10-30 20:12       ` Andrea Righi
2019-10-31 18:16         ` Joe Perches
2019-10-31 22:12           ` Eric W. Biederman
2020-01-03 13:07   ` Bartlomiej Zolnierkiewicz
2020-01-13 11:08     ` [PATCH v2] " Dan Carpenter
2020-01-15 14:31       ` Bartlomiej Zolnierkiewicz [this message]
2020-01-13 12:49     ` [PATCH] " Arnd Bergmann
2020-01-15 13:09       ` Bartlomiej Zolnierkiewicz
2020-01-15 13:16         ` Arnd Bergmann

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