From 18e126e97c961f7a93823795c879d7c085fe5098 Mon Sep 17 00:00:00 2001
From: Chen Zhongjin <chenzhongjin@huawei.com>
Date: Fri, 11 Nov 2022 09:53:26 +0800
Subject: [PATCH] firmware: dmi-sysfs: Fix null-ptr-deref in dmi_sysfs_register_handle
Git-commit: 18e126e97c961f7a93823795c879d7c085fe5098
Patch-mainline: v6.3-rc1
References: git-fixes
KASAN reported a null-ptr-deref error:
Kasan: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
Cpu: 0 PID: 1373 Comm: modprobe
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
Rip: 0010:dmi_sysfs_entry_release
...
Call Trace:
<TASK>
kobject_put
dmi_sysfs_register_handle (drivers/firmware/dmi-sysfs.c:540) dmi_sysfs
dmi_decode_table (drivers/firmware/dmi_scan.c:133)
dmi_walk (drivers/firmware/dmi_scan.c:1115)
dmi_sysfs_init (drivers/firmware/dmi-sysfs.c:149) dmi_sysfs
do_one_initcall (init/main.c:1296)
...
Kernel panic - not syncing: Fatal exception
Kernel Offset: 0x4000000 from 0xffffffff81000000
Acked-by: Takashi Iwai <tiwai@suse.de>
---[ end Kernel panic - not syncing: Fatal exception ]---
It is because previous patch added kobject_put() to release the memory
which will call dmi_sysfs_entry_release() and list_del().
However, list_add_tail(entry->list) is called after the error block,
so the list_head is uninitialized and cannot be deleted.
Move error handling to after list_add_tail to fix this.
Fixes: 660ba678f999 ("firmware: dmi-sysfs: Fix memory leak in dmi_sysfs_register_handle")
Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com>
Link: https://lore.kernel.org/r/20221111015326.251650-2-chenzhongjin@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/firmware/dmi-sysfs.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/firmware/dmi-sysfs.c b/drivers/firmware/dmi-sysfs.c
index 9b6ce172175c..ed5aff0a4204 100644
--- a/drivers/firmware/dmi-sysfs.c
+++ b/drivers/firmware/dmi-sysfs.c
@@ -603,16 +603,16 @@ static void __init dmi_sysfs_register_handle(const struct dmi_header *dh,
*ret = kobject_init_and_add(&entry->kobj, &dmi_sysfs_entry_ktype, NULL,
"%d-%d", dh->type, entry->instance);
- if (*ret) {
- kobject_put(&entry->kobj);
- return;
- }
-
/* Thread on the global list for cleanup */
spin_lock(&entry_list_lock);
list_add_tail(&entry->list, &entry_list);
spin_unlock(&entry_list_lock);
+ if (*ret) {
+ kobject_put(&entry->kobj);
+ return;
+ }
+
/* Handle specializations by type */
switch (dh->type) {
case DMI_ENTRY_SYSTEM_EVENT_LOG:
--
2.35.3