A script to manage the whitelist of package maintainer scripts.

src/scripts/package_script_whitelist.sh

Index: src/scripts/package_script_whitelist.sh
diff --git a/src/scripts/package_script_whitelist.sh b/src/scripts/package_script_whitelist.sh
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+#!/bin/bash
+
+# Copyright (c) 2010 The Chromium OS 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 is used to maintain the whitelist for package maintainer scripts.
+# If a package maintainer script is in the whitelist file then it is ok to skip
+# running that maintainer script when installing the package. Otherwise there
+# should be an equivalent script that can perform those operation on a target
+# root file system.
+#
+# The whitelist contains on entry per line which is the filename followed by
+# its md5sum. Ideally it is kept in sorted by package name like below:
+#    bar.postinst MD5SUM1
+#    bar.postinst MD5SUM2
+#    bar.preinst  MD5SUM3
+#    foo.postinst MD5SUM4
+#
+# TODO: Should be able to whitelist on built packages and not just an already
+# created rootfs.
+
+. "$(dirname "$0")/common.sh"
+
+DEFINE_string whitelist "${SRC_ROOT}/package_scripts/package.whitelist" \
+  "The whitelist file to use."
+DEFINE_string file "" "The path to a presinst/postinst file for add/audit."
+DEFINE_string root "" \
+  "Mounted root on which to look for the maintainer scripts when using audit."
+DEFINE_string audit_pattern "*" \
+  "Package name pattern used when auditing all packages [ex: 'lib*']"
+
+FLAGS_HELP="Usage: $(basename $0) [options] add|audit|check
+
+Use this script to maintain the package scripts whitelist. It handles the
+following commands:
+
+  add: Add the --file= specified file to the whitelist.
+  audit: If no --file= is given, audit all non-whitelisted scripts in the
+         given rootfs. This will show you the files in turn and give you
+         the option to Skip/View/Whitelist/Create template for the script.
+         If --file is given it will do the same for that one file.
+  check: Checks if the --file= is in the whitelist.
+"
+
+# Parse command line
+FLAGS "$@" || exit 1
+eval set -- "${FLAGS_ARGV}"
+
+# Returns true if the input file is whitelisted.
+#
+# $1 - The file to check
+is_whitelisted() {
+  local file=$1
+  local whitelist="$FLAGS_whitelist"
+  test -f "$whitelist" || return
+
+  local checksum=$(md5sum "$file" | awk '{ print $1 }')
+  local count=$(grep -c "$checksum" "${whitelist}" || /bin/true)
+  test $count -ne 0
+}
+
+# Adds a the file at the given path to the whitelist.
+#
+# $1 - Path to file to add to whitelist.
+add_to_whitelist() {
+  local path=$1
+  local whitelist="$FLAGS_whitelist"
+  local file=$(basename "$path")
+
+  local checksum=$(md5sum "$path" | awk '{ print $1 }')
+  if [ ! -f "$whitelist" ]; then
+cat <<EOF > "$whitelist"
+# Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+EOF
+  fi
+
+  echo "$file $checksum" | \
+    sort -u -o "${whitelist}.new" "$whitelist" -
+  mv "${whitelist}.new" "$whitelist"
+}
+
+# Creates a template alternative maintainer script in the same directory
+# as the whitelist file. This will run instead of the whitelisted package
+# scripts using only build machine binaries and targeting a rootfs.
+#
+# $1 - The name of the template (like 'foo.postinst')
+create_script_template() {
+  local file=$1
+
+  local whitelist_dir=$(dirname "$FLAGS_whitelist")
+  local path="${whitelist_dir}/${file}"
+  if [ -f "$path" ]; then
+    echo "Error: Alternative maintainer script '$path' already exists."
+    return
+  fi
+
+cat <<EOF > "$path"
+#!/bin/bash
+
+# Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# \$ROOT - The path to the target root file system.
+# \$SRC_ROOT - The path to the source tree.
+
+# $file
+
+# TODO: The equivalent of $file running from outside of the target rootfs
+# that only uses tools from the build machine and not from the target.
+EOF
+  chmod 0750 "$path"
+}
+
+# Show the script to the user for audit purposes.
+#
+# $1 - The script to show.
+show_script() {
+  local path=$1
+  local type=$(file -b "$path")
+  local is_text=$(echo "$type" | grep -c "text")
+  if [ $is_text -eq 0 ]; then
+    local file=$(basename "$path")
+    echo "Unable to view '$file'; not a text file. Type is '$type'"
+  else
+    local pager="/usr/bin/less"
+    if [ -n "$PAGER" ]; then
+      pager="$PAGER"
+    fi
+    $pager "$path"
+  fi
+}
+
+# Process a given script for audit purposes. We show the script to the user
+# and then prompt them with options.
+#
+# $1 - The script to process
+audit_script() {
+  local path=$1
+  local file=$(basename "$path")
+  local prompt="$file: (Q)uit, (S)kip, (V)iew, (W)hitelist, (C)reate template?"
+
+  show_script "$path"
+  while true; do
+    read -n 1 -p "$prompt " ANSWER
+    echo ""
+    ANSWER="${ANSWER:0:1}" # Get just the first character
+    case $ANSWER in
+      Q*|q*)
+        exit 0
+        ;;
+      S*|s*)
+        echo "Skipping: $file"
+        return
+        ;;
+      V*|v*)
+        show_script "$path"
+        ;;
+      W*|w*)
+        echo "Whitelisting: $file"
+        add_to_whitelist "$path"
+        return
+        ;;
+      C*|c*)
+        echo "Creating template for: $file"
+        create_script_template "$file"
+        ;;
+      *)
+        echo "Unknown response: '$ANSWER'"
+        ;;
+    esac
+  done
+}
+
+# Audit all non-whitelisted script in $FLAGS_root
+audit_all() {
+  echo "Auditing packages at: $FLAGS_root"
+  local dpkg_info="$FLAGS_root/var/lib/dpkg/info"
+  local scripts=$(ls "$dpkg_info"/$FLAGS_audit_pattern.preinst \
+                  "$dpkg_info"/$FLAGS_audit_pattern.postinst | sort -r)
+
+  for s in $scripts; do
+    if ! is_whitelisted "$s"; then
+      audit_script "$s"
+    fi
+  done
+}
+
+case $1 in
+  add)
+    if [ -z "$FLAGS_file" ]; then
+      echo "--file parameter is required for 'add' command."
+      exit 1
+    fi
+    add_to_whitelist "$FLAGS_file"
+    ;;
+  audit)
+    if [ -n "$FLAGS_file" ]; then
+      audit_script "$FLAGS_file"
+    elif [ -n "$FLAGS_root" ]; then
+      audit_all
+    else
+      echo "Error: One of --file or --root is needed for audit command."
+    fi
+    ;;
+  check)
+    if [ -z "$FLAGS_file" ]; then
+      echo "--file parameter is required for 'check' command."
+      exit 1
+    fi
+    if is_whitelisted "$FLAGS_file"; then
+      echo "Whitelisted"
+    else
+      echo "Not whitelisted"
+    fi
+    ;;
+  *)
+  echo "Unknown command."
+  ;;
+esac