fbdev: efifb: Fix a use-after-free due early fb_info cleanup
authorJavier Martinez Canillas <javierm@redhat.com>
Fri, 6 May 2022 13:22:25 +0000 (15:22 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 18 May 2022 08:26:49 +0000 (10:26 +0200)
commitef090cd44dd9150195bd45ab1042dbaa42414b5e
tree20916c344658bf98f1fc0ed6e2cf7c9942956012
parent42125c81ca257ad3fd54eb43c66157b34e711d8c
fbdev: efifb: Fix a use-after-free due early fb_info cleanup

[ Upstream commit 1b5853dfab7fdde450f00f145327342238135c8a ]

Commit d258d00fb9c7 ("fbdev: efifb: Cleanup fb_info in .fb_destroy rather
than .remove") attempted to fix a use-after-free error due driver freeing
the fb_info in the .remove handler instead of doing it in .fb_destroy.

But ironically that change introduced yet another use-after-free since the
fb_info was still used after the free.

This should fix for good by freeing the fb_info at the end of the handler.

Fixes: d258d00fb9c7 ("fbdev: efifb: Cleanup fb_info in .fb_destroy rather than .remove")
Reported-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reported-by: Andrzej Hajda <andrzej.hajda@intel.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
Reviewed-by: Thomas Zimmermann <tzimemrmann@suse.de>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220506132225.588379-1-javierm@redhat.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
drivers/video/fbdev/efifb.c