Bashrc

Nice bashrc options to secure history and auditting

declare -rx HISTCONTROL=""                                  #does not ignore spaces or duplicates
declare -rx HISTIGNORE=""                                   #does not ignore patterns
declare -rx AUDIT_LOGINUSER="$(who -mu | awk '{print $1}')"
declare -rx AUDIT_LOGINPID="$(who -mu | awk '{print $6}')"
declare -rx AUDIT_USER="$USER"                              #defined by pam during su/sudo
declare -rx AUDIT_PID="$$"
declare -rx AUDIT_TTY="$(who -mu | awk '{print $2}')"
declare -rx AUDIT_SSH="$([ -n "$SSH_CONNECTION" ] && echo "$SSH_CONNECTION" | awk '{print $1":"$2"->"$3":"$4}')"
declare -rx AUDIT_STR="[audit $AUDIT_LOGINUSER/$AUDIT_LOGINPID as $AUDIT_USER/$AUDIT_PID on $AUDIT_TTY/$AUDIT_SSH]"
set +o functrace                                            #disable trap DEBUG inherited in functions, command substitutions or subshells, normally the default setting already
shopt -s extglob                                            #enable extended pattern matching operators
function audit_DEBUG() {
  if [ "$BASH_COMMAND" != "$PROMPT_COMMAND" ]               #avoid logging unexecuted commands after 'ctrl-c or 'empty+enter'
  then
    local AUDIT_CMD="$(history 1)"                          #current history command
    if ! logger -p user.info -t "$AUDIT_STR $PWD" "${AUDIT_CMD##*( )?(+([0-9])[^0-9])*( )}"
    then
      echo error "$AUDIT_STR $PWD" "${AUDIT_CMD##*( )?(+([0-9])[^0-9])*( )}"
    fi
  fi
}
function audit_EXIT() {
  local AUDIT_STATUS="$?"
  logger -p user.info -t "$AUDIT_STR" "#=== bash session ended. ==="
  exit "$AUDIT_STATUS"
}
declare -fr +t audit_DEBUG
declare -fr +t audit_EXIT
logger -p user.info -t "$AUDIT_STR" "#=== New bash session started. ===" #audit the session openning
#when a bash command is executed it launches first the audit_DEBUG(),
#then the trap DEBUG is disabled to avoid a useless rerun of audit_DEBUG() during the execution of pipes-commands;
#at the end, when the prompt is displayed, re-enable the trap DEBUG
declare -rx PROMPT_COMMAND="trap 'audit_DEBUG; trap DEBUG' DEBUG"
declare -rx BASH_COMMAND                                    #current command executed by user or a trap
declare -rx SHELLOPT                                        #shell options, like functrace
trap audit_EXIT EXIT