Allow non admin containers to write to mounted volumes on Windows containers

Overview

When I have the following config.toml, that mounts a new volume under c:\\test

config.toml

[[runners]]
  name = "windows-docker"
  url = "http://192.168.190.160:3000"
  token = "LnGUusC8WHWzsxdchh_J"
  executor = "docker-windows"
  [runners.docker]
    tls_verify = false
    privileged = false
    disable_entrypoint_overwrite = false
    oom_kill_disable = false
    disable_cache = false
    volumes = ["c:\\cache", "c:\\test"]
    pull_policy = "if-not-present"
    shm_size = 0
    helper_image = "gitlab/gitlab-runner-helper:x86_64-4c96e5ad-servercore1809"

I try to list the directory of the mount volume for example c:\\test when using an image that is not running as admin:

.gitlab-ci.yml

job:
  image: steveazz/nonadmin-win
  script:
  - dir C:\\test
  after_script:
  - echo "test"

I get permissions denied

job trace

 Running with gitlab-runner 12.9.0 (4c96e5ad)
   on windows-docker LnGUusC8
Preparing the "docker-windows" executor
 Using Docker executor with image steveazz/nonadmin-win ...
 Authenticating with credentials from C:\Users\Administrator/.docker/config.json
 Using locally found image version due to if-not-present pull policy
 Using docker image sha256:bdc4ebbad3c1c642bdeaaa516c4e0d9690df6494f71ee61951e2546fc7f313a6 for gitlab/gitlab-runner-helper:x86_64-4c96e5ad-servercore1809 ...
 Authenticating with credentials from C:\Users\Administrator/.docker/config.json
 Authenticating with credentials from C:\Users\Administrator/.docker/config.json
 Using locally found image version due to if-not-present pull policy
 Using docker image sha256:52925dc1b265efac26bf6788d50d6369f8cfc4441737458c874ee027226592dd for steveazz/nonadmin-win ...
Preparing environment
00:10
 Authenticating with credentials from C:\Users\Administrator/.docker/config.json
 Authenticating with credentials from C:\Users\Administrator/.docker/config.json
 Running on RUNNER-LNGUUSC8 via 
 vagrant-2019...
Getting source from Git repository
00:10
 Authenticating with credentials from C:\Users\Administrator/.docker/config.json
 Authenticating with credentials from C:\Users\Administrator/.docker/config.json
 Fetching changes with git depth set to 50...
 Reinitialized existing Git repository in c:/builds/root/playground/.git/
 From http://192.168.190.160:3000/root/playground
  * [new ref]         refs/pipelines/420 -> refs/pipelines/420
    a985f5d..3b4fb64  nonroot-windows    -> origin/nonroot-windows
 Checking out 3b4fb646 as nonroot-windows...
 git-lfs/2.7.1 (GitHub; windows amd64; go 1.11.5; git 6b7fb6e3)
 Skipping Git submodules setup
Restoring cache
 Authenticating with credentials from C:\Users\Administrator/.docker/config.json
 Authenticating with credentials from C:\Users\Administrator/.docker/config.json
Downloading artifacts
 Authenticating with credentials from C:\Users\Administrator/.docker/config.json
 Authenticating with credentials from C:\Users\Administrator/.docker/config.json
Running before_script and script
 Authenticating with credentials from C:\Users\Administrator/.docker/config.json
 $ dir C:\\test
 dir : Access to the path 'C:\test' is denied.
 At line:1 char:1
 + dir C:\\test
 + ~~~~~~~~~~~~
     + CategoryInfo          : PermissionDenied: (C:\test:String) [Get-ChildIte 
    m], UnauthorizedAccessException
     + FullyQualifiedErrorId : DirUnauthorizedAccessError,Microsoft.PowerShell. 
    Commands.GetChildItemCommand
  
Running after_script
 Running after script...
 $ echo "test"
 test
Uploading artifacts for failed job
 Authenticating with credentials from C:\Users\Administrator/.docker/config.json
 Authenticating with credentials from C:\Users\Administrator/.docker/config.json
 ERROR: Job failed: exit code 1

On Linux this works