When a docker is running with privileges, majority of the use case is to have some program running with root then drop privileges to another user. i.e. httpd to start with privileged and bind to port 80, then drop privileges to www user.
- We should add security check for submitting users, to verify they have "sudo" access to run privileged container.
- We should remove --user=uid:gid for privileged containers.
Docker can be launched with --privileged=true, and --user=uid:gid flag. With this parameter combinations, user will not have access to become root user. All docker exec command will be drop to uid:gid user to run instead of granting privileges. User can gain root privileges if container file system contains files that give user extra power, but this type of image is considered as dangerous. Non-privileged user can launch container with special bits to acquire same level of root power. Hence, we lose control of which image should be run with --privileges, and who have sudo rights to use privileged container images. As the result, we should check for sudo access then decide to parameterize --privileged=true OR --user=uid:gid. This will avoid leading developer down the wrong path.