From d3d19d6fc5736a798b118971935ce274f7deaa82 Mon Sep 17 00:00:00 2001
From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Mon, 13 Jan 2020 14:08:14 +0300
Subject: fbdev: potential information leak in do_fb_ioctl()
Git-commit: d3d19d6fc5736a798b118971935ce274f7deaa82
Patch-mainline: v5.7-rc1
References: bsc#1114279

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>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andrea Righi <righi.andrea@gmail.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Peter Rosin <peda@axentia.se>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200113100132.ixpaymordi24n3av@kili.mountain
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/video/fbdev/core/fbmem.c |   12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -769,7 +769,7 @@ fb_read(struct file *file, char __user *
 
 	if (info->fbops->fb_read)
 		return info->fbops->fb_read(info, buf, count, ppos);
-	
+
 	total_size = info->screen_size;
 
 	if (total_size == 0)
@@ -834,7 +834,7 @@ fb_write(struct file *file, const char _
 
 	if (info->fbops->fb_write)
 		return info->fbops->fb_write(info, buf, count, ppos);
-	
+
 	total_size = info->screen_size;
 
 	if (total_size == 0)
@@ -1062,7 +1062,7 @@ EXPORT_SYMBOL(fb_set_var);
 
 int
 fb_blank(struct fb_info *info, int blank)
-{	
+{
 	struct fb_event event;
 	int ret = -EINVAL, early_ret;
 
@@ -1133,7 +1133,7 @@ static long do_fb_ioctl(struct fb_info *
 	case FBIOGET_FSCREENINFO:
 		if (!lock_fb_info(info))
 			return -ENODEV;
-		fix = info->fix;
+		memcpy(&fix, &info->fix, sizeof(fix));
 		unlock_fb_info(info);
 
 		ret = copy_to_user(argp, &fix, sizeof(fix)) ? -EFAULT : 0;
@@ -1495,7 +1495,7 @@ out:
 	return res;
 }
 
-static int 
+static int
 fb_release(struct inode *inode, struct file *file)
 __acquires(&info->lock)
 __releases(&info->lock)
@@ -1693,7 +1693,7 @@ static int do_register_framebuffer(struc
 			fb_info->pixmap.access_align = 32;
 			fb_info->pixmap.flags = FB_PIXMAP_DEFAULT;
 		}
-	}	
+	}
 	fb_info->pixmap.offset = 0;
 
 	if (!fb_info->pixmap.blit_x)