Linux container and rights on shared folder: can't change them

i run a gitea container on widows with the following command:

> docker run -d --name=gitea -p 10022:22 -p 10080:3000 -v d:\data\docker\gitea:/data gitea/gitea:latest

the container runs an ssh service but, the certificates are in /data/ssh, that is on the windows file system.
I get the following error message:

Permissions 0777 for '/data/ssh/certificate_name' are too open.
It is recommended that your private key files are NOT accessible by others.
This private key will be ignored.

but, when I try to use chmod, it has no effect on the files on the shared drive…

What may I do ?