!8775 llc: verify mac len before reading mac header

Merge Pull Request from: @ci-robot 
 
PR sync from: Dong Chenchen <dongchenchen2@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/UQJ5KACJSLK2OZHAGK7XN6DBUR3U6JD6/ 
 
https://gitee.com/src-openeuler/kernel/issues/I9RG0B 
 
Link:https://gitee.com/openeuler/kernel/pulls/8775

 

Reviewed-by: Yue Haibing <yuehaibing@huawei.com>
Reviewed-by: Liu YongQiang <liuyongqiang13@huawei.com>
Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>