From 54e6ef353ecf05be0f0c847ac0a86f55f69a84d0 Mon Sep 17 00:00:00 2001
From: Javier Martinez Canillas <javierm@redhat.com>
Date: Fri, 6 May 2022 15:22:25 +0200
Subject: fbdev: efifb: Fix a use-after-free due early fb_info cleanup
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Git-commit: 1b5853dfab7fdde450f00f145327342238135c8a
Patch-mainline: v5.18-rc7
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225
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
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/video/fbdev/efifb.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/video/fbdev/efifb.c b/drivers/video/fbdev/efifb.c
index cfa3dc0b4eee..b3d5f884c544 100644
--- a/drivers/video/fbdev/efifb.c
+++ b/drivers/video/fbdev/efifb.c
@@ -259,12 +259,12 @@ static void efifb_destroy(struct fb_info *info)
memunmap(info->screen_base);
}
- framebuffer_release(info);
-
if (request_mem_succeeded)
release_mem_region(info->apertures->ranges[0].base,
info->apertures->ranges[0].size);
fb_dealloc_cmap(&info->cmap);
+
+ framebuffer_release(info);
}
static const struct fb_ops efifb_ops = {
--
2.38.1