Class: OsCtld::UserControl::Supervisor::NamespacedClientHandler

Inherits:
Generic::ClientHandler show all
Defined in:
lib/osctld/user_control/supervisor.rb

Overview

Client handler for commands called from a container’s user namespace.

The handler finds appropriate osctld user and passes control to standard client handler.

Instance Attribute Summary

Attributes inherited from Generic::ClientHandler

#opts

Instance Method Summary collapse

Methods inherited from Generic::ClientHandler

#communicate, #error, #error!, #initialize, #ok, #parse, #reply_error, #reply_ok, #request_stop, #send_data, #send_update, #server_version, #socket

Constructor Details

This class inherits a constructor from OsCtld::Generic::ClientHandler

Instance Method Details

#handle_cmd(req) ⇒ Object 



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# File 'lib/osctld/user_control/supervisor.rb', line 24

def handle_cmd(req)
  return error('invalid input') unless req.is_a?(Hash)

  # For now, allow only ct_autodev
  unless %w[ct_autodev ct_pre_mount ct_post_mount].include?(req[:cmd])
    return error('invalid cmd')
  end

  # Find out which user has connected
  cred = @sock.getsockopt(Socket::SOL_SOCKET, Socket::SO_PEERCRED)
  pid, uid, gid = cred.unpack('LLL')

  # Locate the user in DB using the uid of the caller process' grandparent:
  # - caller: lxc hook
  # - parent: lxc-start, future /sbin/init
  # - grandparent: lxc-start running within the host namespace
  process = OsCtl::Lib::OsProcess.new(pid)
  gpuid = process.grandparent.ruid

  user = DB::Users.get.detect do |u|
    u.pool.name == req[:opts][:pool] && u.ugid == gpuid
  end

  unless user
    log(:warn, "Unable to find user for pid=#{pid},uid=#{uid},gid=#{gid}")
    return error('invalid user')
  end

  # Just to be sure that we have the right user, compare the caller's
  # uid/gid with the user's uid/gid within user namespace.
  {
    uid: [user.uid_map.ns_to_host(0), uid],
    gid: [user.gid_map.ns_to_host(0), gid]
  }.each do |type, ids|
    expected, got = ids

    next unless expected != got

    log(:warn, "Caller's #{type} does not match the located user: " \
               "user=#{user.ident}, expected #{type}=#{expected}, " \
               "got #{type}=#{got}")
    return error('invalid user')
  end

  req[:opts].update(client_pid: pid) if req[:opts].is_a?(Hash)

  # Forward to a real client handler
  log(:info, "Forwarding request to user #{user.ident}")
  handler = ClientHandler.new(@sock, user:)
  handler.handle_cmd(req)
end

#log_type ⇒ Object 



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# File 'lib/osctld/user_control/supervisor.rb', line 76

def log_type
  self.class.name
end