security.d/chk_passwd

#!/bin/bash
#
#############################################################################
# Copyright (C) 2005-2012
#   
# Michiel Broek               <mbse@mbse.eu>
# Beekmansbos 10
# 1971 BV IJmuiden
# the Netherlands
#
# This file is part of SlackSecCheckScripts.
#
# This package is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 2, or (at your option) any
# later version.
#
# SlackSecCheckScripts is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.
# 
# You should have received a copy of the GNU General Public License
# along with MBSE BBS; see the file COPYING.  If not, write to the Free
# Software Foundation, 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
#############################################################################


PATH=/sbin:/usr/sbin:/bin:/usr/bin

umask 077
TZ=UTC; export TZ
LANG=C; export LANG

max_loginlen=${max_loginlen:-32}

MP=/etc/passwd
SP=/etc/shadow


SECUREDIR=`mktemp -d /tmp/_securedir.XXXXXX` || exit 1

trap "/bin/rm -rf $SECUREDIR ; exit 0" EXIT INT QUIT PIPE

if ! cd "$SECUREDIR"; then
        echo "Can not cd to $SECUREDIR".
        exit 1
fi

TMP2=secure1.$$
MPBYUID=secure2.$$
COMBINED=secure3.$$
OUTPUT=secure4.$$


# Combine passwd and shadow files.
#
JOPT=$( join --help | grep "\--nocheck-order")
if [ -z "$JOPT" ]; then
    join -t : -j 1 $MP $SP > $COMBINED
else
    join --nocheck-order -t : -j 1 $MP $SP > $COMBINED
fi


# These are used several times.
#
awk -F: '!/^+/ { print $1 " " $3 }' $MP | sort -k2n > $MPBYUID


# Check the master password file syntax.
# Usernames may have a $ character at the end for Samba
# machine and trust accounts.
#
awk -v "len=$max_loginlen" '
    BEGIN {
	while ( getline < "/etc/shells" > 0 ) {
	    if ($0 ~ /^\#/ || $0 ~ /^$/ )
		continue;
	    shells[$1]++;
	}
	FS=":";
    }

    {
        if ($0 ~ /^[     ]*$/) {
            printf "\tLine %d is a blank line.\n", NR;
            next;
        }
        if (NF != 15 && ($1 != "+" || NF != 1))
            printf "\tLine %d has the wrong number of fields.\n", NR;
        if ($1 == "+" )  {
            if (NF != 1 && $3 == 0)
                printf "\tLine %d includes entries with uid 0.\n", NR;
            next;
        }
        if ($1 !~ /^[A-Za-z0-9]([-A-Za-z0-9_]*[A-Za-z0-9\$])*$/)
            printf "\tLogin %s has non-alphanumeric characters.\n", $1;
        if (length($1) > len)
            printf "\tLogin %s has more than "len" characters.\n", $1;
	if ($7 == "" && $8 !~ /!/ && $8 != "*")
	    printf "\tLogin %s does not have a shell\n", $1;
        if ($7 != "" && ! shells[$7] && $8 !~ /!/ && $8 != "*")
            printf "\tLogin %s does not have a valid shell (%s)\n", $1, $7;
	if ($7 != "" && shells[$7] && ($8 ~ /!/ && $8 = "*"))
	    printf "\tLogin %s account is locked.\n", $1;
	if ($8 == "")
	    printf "\tLogin %s has no password.\n", $1;
	if ($9 == "0")
	    printf "\tLogin %s password is expired.\n", $1;
        if ($3 == 0 && $1 != "root" && $1 != "toor")
            printf "\tLogin %s has a user id of 0.\n", $1;
        if ($3 < 0)
            printf "\tLogin %s has a negative user id.\n", $1;
	if ($4 < 0)
            printf "\tLogin %s has a negative group id.\n", $1;
    }' < $COMBINED > $OUTPUT
if [ -s $OUTPUT ] ; then
    printf "\nChecking the $MP and $SP files:\n"
    cat $OUTPUT
fi

awk -F: '{ print $1 }' $MP | sort | uniq -d > $OUTPUT
if [ -s $OUTPUT ] ; then
    printf "\n$MP has duplicate user names.\n"
    column $OUTPUT
fi

# To not exclude 'toor', a standard duplicate root account, from the duplicate
# account test, uncomment the line below (without egrep in it)and comment
# out the line (with egrep in it) below it.
#
#< $MPBYUID uniq -d -f 1 | awk '{ print $2 }' > $TMP2
< $MPBYUID egrep -v '^toor ' | uniq -d -f 1 | awk '{ print $2 }' > $TMP2
if [ -s $TMP2 ] ; then
    printf "\n$MP has duplicate user id's.\n"
    while read uid; do
        grep -w $uid $MPBYUID
    done < $TMP2 | column
fi