xrdp/tools/chkpriv/xrdp-chkpriv.in

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#!/bin/sh
#
# xrdp: A Remote Desktop Protocol server.
#
# Copyright (C) Jay Sorg and contributors 2004-2024
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
# Program to check permissions for xrdp when running in a non-privileged
# mode
# Change these if they do not match your installation
CONF_DIR=@sysconfdir@/xrdp
XRDP_INI="$CONF_DIR"/xrdp.ini
SESMAN_INI="$CONF_DIR"/sesman.ini
RSAKEYS_INI="$CONF_DIR"/rsakeys.ini
DROPPRIV=@pkglibexecdir@/xrdp-droppriv
# -----------------------------------------------------------------------------
# G E T I N I V A L U E
#
# Gets a value from an ini file.
#
# Params [ini_file] [key]
# -----------------------------------------------------------------------------
GetIniValue()
{
# Look for a line matching 'key=' with optional whitespace
# either side of the key. When we find one, strip everything
# up to and including the first '=', print it, and quit
#
# This doesn't take sections into account
sed -n -e '/^ *'"$2"' *=/{
s/^[^=]*=//p
q
}' "$1"
}
# -----------------------------------------------------------------------------
# M A I N
# -----------------------------------------------------------------------------
if [ "$(id -u)" != 0 ]; then
echo "** Must run this script as root" >&2
exit 1
fi
OS=$(uname)
case "$OS" in
FreeBSD | Linux) ;;
*) echo "Unsupported operating system $OS" >&2
exit 1
esac
errors=0
runtime_user=$(GetIniValue "$XRDP_INI" runtime_user)
runtime_group=$(GetIniValue "$XRDP_INI" runtime_group)
certificate=$(GetIniValue "$XRDP_INI" certificate)
key_file=$(GetIniValue "$XRDP_INI" key_file)
SessionSockdirGroup=$(GetIniValue "$SESMAN_INI" SessionSockdirGroup)
case "$certificate" in
'') certificate="$CONF_DIR"/cert.pem ;;
/*) ;;
*) certificate="$CONF_DIR"/"$certificate"
esac
case "$key_file" in
'') key_file="$CONF_DIR"/key.pem ;;
/*) ;;
*) key_file="$CONF_DIR"/"$key_file"
esac
echo "Settings"
echo " - [xrdp.ini] runtime_user : $runtime_user"
echo " - [xrdp.ini] runtime_group : $runtime_group"
echo " - [xrdp.ini] certificate : $certificate"
echo " - [xrdp.ini] key_file : $key_file"
echo " - [sesman.ini] SessionSockdirGroup : $SessionSockdirGroup"
echo
# Basic checks on runtime user/group
if [ -z "$runtime_user" ] && [ -z "$runtime_group" ]; then
echo "-Info- This system is not configured to run xrdp without privilege"
exit 0
fi
if [ -z "$runtime_user" ] || [ -z "$runtime_group" ]; then
echo "-Error- Both 'runtime_user' and 'runtime_group' must be set"
errors=$(( errors + 1 ))
exit 1
fi
if getent passwd "$runtime_user" >/dev/null ; then
echo "-Info- runtime_user '$runtime_user' appears to exist"
else
echo "-Error- runtime_user '$runtime_user' does not exist"
errors=$(( errors + 1 ))
fi
GID=
if getent group "$runtime_group" >/dev/null ; then
echo "-Info- runtime_group '$runtime_group' appears to exist"
GID=$(getent group xrdp | cut -d: -f3)
else
echo "-Error- runtime_group '$runtime_group' does not exist"
errors=$(( errors + 1 ))
fi
# Groups agree between sesman and xrdp?
if [ "$runtime_user" = "$SessionSockdirGroup" ]; then
echo "-Info- xrdp.ini and sesman.ini agree on group ownership"
else
echo "-Error- xrdp.ini and sesman.ini do not agree on group ownership"
errors=$(( errors + 1 ))
fi
# Check we can access rsakeys.ini
#
# This is our file, so we can be completely prescriptive about
# the permissions
if [ -e $RSAKEYS_INI ]; then
# Only check if we have a GID
if [ -n "$GID" ]; then
# Get the permissions, UID and GID in $1..$3
case "$OS" in
FreeBSD)
# shellcheck disable=SC2046
set -- $(stat -f "%Lp %u %g" $RSAKEYS_INI)
;;
*)
# shellcheck disable=SC2046
set -- $(stat -c "%a %u %g" $RSAKEYS_INI)
esac
if [ "$1/$2/$3" = "640/0/$GID" ]; then
echo "-Info- $RSAKEYS_INI has correct permissions"
else
if [ "$1" != 640 ]; then
echo "-Error- $RSAKEYS_INI should have permissions -rw-r-----"
errors=$(( errors + 1 ))
fi
if [ "$2" != 0 ]; then
echo "-Error- $RSAKEYS_INI should be owned by root"
errors=$(( errors + 1 ))
fi
if [ "$3" != "$GID" ]; then
echo "-Error- $RSAKEYS_INI should be in the $runtime_group group"
errors=$(( errors + 1 ))
fi
fi
fi
else
echo "-Error- $RSAKEYS_INI does not exist"
errors=$(( errors + 1 ))
fi
# Are cert and key readable (but NOT writeable) by the user?
#
# These aren't necessarily our files, so we can't be too prescriptive about
# privileges. On Debian for example, we might be using the 'ssl-cert'
# group to obtain access to /etc/ssl/private/ssl-cert-snakeoil.key
for file in "$certificate" "$key_file"; do
if ! [ -e $file ]; then
echo "-Error- $file does not exist"
errors=$(( errors + 1 ))
elif ! $DROPPRIV "$runtime_user" "$runtime_group" sh -c '[ -r '"$file"' ]'
then
echo "-Error- $file is not readable by $runtime_user:$runtime_group"
errors=$(( errors + 1 ))
elif $DROPPRIV "$runtime_user" "$runtime_group" sh -c '[ -w '"$file"' ]'
then
echo "-Error- $file is writeable by $runtime_user:$runtime_group"
errors=$(( errors + 1 ))
else
echo "-Info- $file is read-only for $runtime_user:$runtime_group"
fi
done
echo
if [ $errors -eq 0 ]; then
echo "-Summary- Permissions appear to be correct to run xrdp unprivileged"
status=0
else
echo "-Summary- $errors error(s) found. Please correct these and try again"
status=1
fi
exit $status