!1596 ksmbd: fix out-of-bound read in deassemble_neg_contexts()

Merge Pull Request from: @ci-robot 
 
PR sync from: Li Lingfeng <lilingfeng3@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/MKD6POKWLXC45KXPZXCZ7N52MPOZMNAR/ 
 
https://gitee.com/src-openeuler/kernel/issues/I7LU2Q 
 
Link:https://gitee.com/openeuler/kernel/pulls/1596

 

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