stable inclusion
from linux-4.19.141
commit a906b868953a9c9bba44649a8fe760e818dd7224
CVE: CVE-2020-25212

--------------------------------

[ Upstream commit b4487b93 ]

Move the buffer size check to decode_attr_security_label() before memcpy()
Only call memcpy() if the buffer is large enough

Fixes: aa9c2669 ("NFS: Client implementation of Labeled-NFS")
Signed-off-by: NJeffrey Mitchell <jeffrey.mitchell@starlab.io>
[Trond: clean up duplicate test of label->len != 0]
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>