linux-kernel - [PATCH] drivers/firmware: Fix double free in dmi_sysfs_register

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Message-Id: <20210310072459.5029-1-lyl2019@mail.ustc.edu.cn>
Date:   Tue,  9 Mar 2021 23:24:59 -0800
From:   Lv Yunlong <lyl2019@...l.ustc.edu.cn>
To:     gustavo@...eddedor.com, gregkh@...e.de, mikew@...gle.com
Cc:     linux-kernel@...r.kernel.org, Lv Yunlong <lyl2019@...l.ustc.edu.cn>
Subject: [PATCH] drivers/firmware: Fix double free in dmi_sysfs_register_handle

A double free bug was found in drivers/firmware/dmi-sysfs.c.
In the implementation of dmi_sysfs_register_handle, it calls
dmi_system_event_log() to initialize entry->child. If
kobject_init_and_add() failed, entry->child is freed. But
unfortunately, out_err branch in dmi_sysfs_register_handle
will freed entry->child twice!

Fixes: 925a1da7477fc ("firmware: Break out system_event_log in dmi-sysfs")
Signed-off-by: Lv Yunlong <lyl2019@...l.ustc.edu.cn>
---
 drivers/firmware/dmi-sysfs.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/firmware/dmi-sysfs.c b/drivers/firmware/dmi-sysfs.c
index 8b8127fa8955..ad97bbd37206 100644
--- a/drivers/firmware/dmi-sysfs.c
+++ b/drivers/firmware/dmi-sysfs.c
@@ -631,7 +631,6 @@ static void __init dmi_sysfs_register_handle(const struct dmi_header *dh,
 
 	return;
 out_err:
-	kobject_put(entry->child);
 	kobject_put(&entry->kobj);
 	return;
 }
-- 
2.25.1