• Chen Zhongjin's avatar
    firmware: dmi-sysfs: Fix null-ptr-deref in dmi_sysfs_register_handle · 18e126e9
    Chen Zhongjin authored
    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: 660ba678 ("firmware: dmi-sysfs: Fix memory leak in dmi_sysfs_register_handle")
    Signed-off-by: default avatarChen Zhongjin <chenzhongjin@huawei.com>
    Link: https://lore.kernel.org/r/20221111015326.251650-2-chenzhongjin@huawei.comSigned-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    18e126e9
dmi-sysfs.c 17 KB