SQUID3 - using multiple auth_param like basic_ncsa_auth & basic_ldap_auth - bash

Question

i tried to setup squid3 with multiple auth_param. Basically, the first choice should be basic_ldap_auth and if this doesnt return OK it should try basic_ncsa_auth with the same values. As far as i know squid doesnt support it however there is the possibility to use "external" ACL
auth_param basic program /usr/lib/squid3/basic_fake_auth
external_acl_type MultAuth %SRC %LOGIN %{Proxy-Authorization} /etc/squid3/multAuth.pl
acl extAuth external MultAuth
my "multAuth.pl"
use URI::Escape;
use MIME::Base64;
$|=1;
while (<>) {
($ip,$user,$auth) = split();
# Retrieve the password from the authentication header
$auth = uri_unescape($auth);
($type,$authData) = split(/ /, $auth);
$authString = decode_base64($authData);
($username,$password) = split(/:/, $authString);
# do the authentication and pass results back to Squid.
$ldap = `/bin/bash auth/ldap.sh`;
if ($ldap == "OK") {
print "OK";
}
$ncsa = `/bin/bash auth/ncsa.sh`;
if ($ncsa == "OK") {
print "OK";
} else {
print "ERR";
}
}
now i am trying to run with ncsa.sh and ldap.sh the "normal" shell command for these auth methods.
./basic_ldap_auth -R -b "dc=domain,dc=de" -D "CN=Administrator,CN=Users,DC=domain,DC=de" -w "password" -f sAMAccountName=%s -h domain.de
user password
and
./basic_ncsa_auth /etc/squid3/users
user password
Therefor i ran:
auth/ncsa.sh
#!/usr/bin/expect
eval spawn [lrange $argv 0 end]
expect ""
send [lindex $argv 1]
send '\r'
expect {
"OK" {
echo OK
exp_continue
}
"ERR" {
echo ERR
exp_continue
}
interact
with
./ncsa.sh "/usr/lib/squid3/basic_ncsa_auth /etc/squid3/users" "user password"
and i generate the following error:
couldn't execute "/usr/lib/squid3/basic_ncsa_auth /etc/squid3/users": no such file or directory
while executing
"spawn {/usr/lib/squid3/basic_ncsa_auth /etc/squid3/users} {user password}"
("eval" body line 1)
invoked from within
"eval spawn [lrange $argv 0 end]"
(file "./ncsa.sh" line 2)
Besides this error, i am not sure how to pass the variables (username & password) forward and i am also not sure how to answer the shell questions like for example the user & pw input for basic_ldap_auth .
Is there a nice way how to solve that? or any other good plan ?
thanks!

Answer 1

FWIW, the following script helped me transition from passwd based to LDAP based authentication.
Contrary to your requirements, my script acts the other way around: It first checks passwd, then LDAP.
#!/usr/bin/env bash
# multiple Squid basic auth checks
# originally posted here: https://github.com/HackerHarry/mSquidAuth
#
# credits
# https://stackoverflow.com/questions/24147067/verify-user-and-password-against-a-file-created-by-htpasswd/40131483
# https://stackoverflow.com/questions/38710483/how-to-stop-ldapsearch1-from-base64-encoding-userpassword-and-other-attributes
#
# requires ldap-utils, openssl and perl
# tested with Squid 4 using a "auth_param basic program /usr/lib/squid/mSquidAuth.sh" line
# authenticate first against squid password file
# if this fails, try LDAP (Active Directory) and also check group membership
# variables
# sLOGFILE=/var/log/squid/mSquidAuth.log
sPWDFILE="/etc/squid/passwd"
sLDAPHOST="ldaps://dc.domain.local:636"
sBASE="DC=domain,DC=local"
sLDS_OPTIONS="-o ldif-wrap=no -o nettimeout=7 -LLL -P3 -x "
sBINDDN="CN=LDAP-read-user,OU=Users,DC=domain,DC=local"
sBINDPW="read-user-password"
sGROUP="Proxy-Users"
# functions
function _grantAccess {
# echo "access granted - $sUSER" >>$sLOGFILE
echo "OK"
}
function _denyAccess {
# echo "access denied - $sUSER" >>$sLOGFILE
echo "ERR"
}
function _setUserAndPass {
local sAuth="$1"
local sOldIFS=$IFS
IFS=' '
set -- $sAuth
IFS=$sOldIFS
# set it globally
sUSER="$1"
sPASS="$2"
}
# loop
while (true); do
read -r sAUTH
sUSER=""
sPASS=""
sSALT=""
sUSERENTRY=""
sHASHEDPW=""
sUSERDN=""
iDNCOUNT=0
if [ -z "$sAUTH" ]; then
# echo "exiting" >>$sLOGFILE
exit 0
fi
_setUserAndPass "$sAUTH"
sUSERENTRY=$(grep -E "^${sUSER}:" "$sPWDFILE")
if [ -n "$sUSERENTRY" ]; then
sSALT=$(echo "$sUSERENTRY" | cut -d$ -f3)
if [ -n "$sSALT" ]; then
sHASHEDPW=$(openssl passwd -apr1 -salt "$sSALT" "$sPASS")
if [ "$sUSERENTRY" = "${sUSER}:${sHASHEDPW}" ]; then
_grantAccess
continue
fi
fi
fi
# LDAP is next
iDNCOUNT=$(ldapsearch $sLDS_OPTIONS -H "$sLDAPHOST" -D "$sBINDDN" -w "$sBINDPW" -b "$sBASE" "(|(sAMAccountName=${sUSER})(userPrincipalName=${sUSER}))" dn 2>/dev/null | grep -cE 'dn::? ')
if [ $iDNCOUNT != 1 ]; then
# user needs a unique account
_denyAccess
continue
fi
# get user's DN
# we need the extra grep in case we get lines back starting with "# refldap" :/
sUSERDN=$(ldapsearch $sLDS_OPTIONS -H "$sLDAPHOST" -D "$sBINDDN" -w "$sBINDPW" -b "$sBASE" "(|(sAMAccountName=${sUSER})(userPrincipalName=${sUSER}))" dn 2>/dev/null | perl -MMIME::Base64 -n -00 -e 's/\n +//g;s/(?<=:: )(\S+)/decode_base64($1)/eg;print' | grep -E 'dn::? ' | sed -r 's/dn::? //')
# try and bind using that DN to check password validity
# also test if that user is member of a particular group
# backslash in DN needs special treatment
if ldapsearch $sLDS_OPTIONS -H "$sLDAPHOST" -D "$sUSERDN" -w "$sPASS" -b "$sBASE" "name=${sGROUP}" member 2>/dev/null | perl -MMIME::Base64 -n -00 -e 's/\n +//g;s/(?<=:: )(\S+)/decode_base64($1)/eg;print' | grep -q "${sUSERDN/\\/\\\\}"; then
_grantAccess
continue
fi
_denyAccess
done