Add the chroot creator to the default set of allowed groups (with override flag).

build/install-chroot.sh

 #!/bin/bash -e
 
 # Copyright (c) 2010 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # This script installs Debian-derived distributions in a chroot environment.
 # It can for example be used to have an accurate 32bit build and test
 # environment when otherwise working on a 64bit machine.
 # N. B. it is unlikely that this script will ever work on anything other than a
 # Debian-derived system.
 
 usage() {
-  echo "usage: ${0##*/} [-m mirror]"
-  echo "-m mirror  an alternate repository mirror for package downloads"
-  echo "-h         this help message"
+  echo "usage: ${0##*/} [-m mirror] [-g group,...]"
+  echo "-g group,... groups that can use the chroot unauthenticated"
+  echo "             Default: 'admin' and current user's group ('$(id -gn)')"
+  echo "-m mirror    an alternate repository mirror for package downloads"
+  echo "-h           this help message"
 }
 
 process_opts() {
   local OPTNAME OPTIND OPTERR OPTARG
-  while getopts ":m:h" OPTNAME; do
+  while getopts ":g:m:h" OPTNAME; do
     case "$OPTNAME" in
+      g)
+        [ -n "${OPTARG}" ] &&
+          chroot_groups="${chroot_groups}${chroot_groups:+,}${OPTARG}"
+        ;;
       m)
         if [ -n "${mirror}" ]; then
           echo "You can only specify exactly one mirror location"
           usage
           exit 1
         fi
         mirror="$OPTARG"
         ;;
       h)
         usage
@@ skipping 127 matching lines @@
  grep ubuntu.com /usr/share/debootstrap/scripts/"${distname}" >&/dev/null &&
    mirror="http://archive.ubuntu.com/ubuntu" ||
    mirror="http://ftp.us.debian.org/debian"
 fi
  sudo debootstrap ${archflag} "${distname}" /var/lib/chroot/"${target}"        \
                   "$mirror"
 
 # Add new entry to /etc/schroot/schroot.conf
 grep ubuntu.com /usr/share/debootstrap/scripts/"${distname}" >&/dev/null &&
   brand="Ubuntu" || brand="Debian"
+if [ -z "${chroot_groups}" ]; then
+  chroot_groups="admin,$(id -gn)"
+fi
 sudo sh -c 'cat >>/etc/schroot/schroot.conf' <<EOF
 [${target%bit}]
 description=${brand} ${distname} ${arch}
 type=directory
 directory=/var/lib/chroot/${target}
 priority=3
 users=root
-groups=admin
-root-groups=admin
+groups=${chroot_groups}
+root-groups=${chroot_groups}
 personality=linux$([ "${arch}" != 64bit ] && echo 32)
 script-config=script-${target}
 
 EOF
 
 # Set up a special directory that changes contents depending on the target
 # that is executing.
 sed '/^FSTAB=/s,/mount-defaults",/mount-'"${target}"'",'                       \
          /etc/schroot/script-defaults |
   sudo sh -c 'cat >/etc/schroot/script-'"${target}"
@@ skipping 102 matching lines @@
 
 Successfully installed ${distname} ${arch}
 
 You can run programs inside of the chroot by invoking the "${target%bit}"
 command.
 
 Your home directory is shared between the host and the chroot. But I configured
 $HOME/chroot to be private to the chroot environment. You can use it
 for files that need to differ between environments.
 EOF