From: Chen Zhongjin <chenzhongjin@huawei.com> mainline inclusion from mainline-v6.3-rc1 commit 18e126e97c961f7a93823795c879d7c085fe5098 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IBP6BN CVE: CVE-2022-49370 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- 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 ---[ 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> Signed-off-by: Xia Fukun <xiafukun@huawei.com> --- 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 5d6b497d54d0..795affb79500 100644 --- a/drivers/firmware/dmi-sysfs.c +++ b/drivers/firmware/dmi-sysfs.c @@ -601,16 +601,16 @@ 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: -- 2.34.1