!1911 ksmbd: fix out-of-bound read in smb2_write

Merge Pull Request from: @ci-robot 
 
PR sync from: Li Lingfeng <lilingfeng3@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/HHXTEKWL4Z4QJ3KP2L5HPOTKEBYCOF2D/ 
 
https://gitee.com/src-openeuler/kernel/issues/I7ST5T 
 
Link:https://gitee.com/openeuler/kernel/pulls/1911

 

Reviewed-by: Jialin Zhang <zhangjialin11@huawei.com>
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>