problems with kerberos authentication

[Jose Lopes]

Hi,

I'm trying to get the squid helper squid_kerb_auth to work against our
Active Directory (win 2003 r2).

I'm using squid 3.0.STABLE14

Squid Cache: Version 3.0.STABLE14
configure options:  '--build=x86_64-mandriva-linux-gnu' '--prefix=/usr'
'--exec-prefix=/usr' '--bindir=/usr/sbin' '--sbindir=/usr/sbin'
'--sysconfdir=/etc/squid' '--datadir=/usr/share'
'--includedir=/usr/include' '--libdir=/usr/lib64'
'--libexecdir=/usr/lib64/squid' '--localstatedir=/var'
'--sharedstatedir=/usr/com' '--mandir=/usr/share/man'
'--infodir=/usr/share/info' '--x-includes=/usr/include'
'--x-libraries=/usr/lib64' '--enable-shared=yes' '--enable-static=no'
'--enable-xmalloc-statistics' '--enable-carp' '--enable-async-io'
'--enable-storeio=aufs,diskd,null,ufs'
'--enable-disk-io=AIO,Blocking,DiskDaemon,DiskThreads'
'--enable-removal-policies=heap,lru' '--enable-icmp'
'--enable-delay-pools' '--disable-esi' '--enable-icap-client'
'--enable-useragent-log' '--enable-referer-log' '--enable-wccp'
'--enable-wccpv2' '--disable-kill-parent-hack' '--enable-snmp'
'--enable-cachemgr-hostname=localhost' '--enable-arp-acl'
'--enable-htcp' '--enable-ssl' '--enable-forw-via-db'
'--enable-cache-digests' '--disable-poll' '--enable-epoll'
'--enable-linux-netfilter' '--disable-ident-lookups'
'--enable-default-hostsfile=/etc/hosts'
'--enable-auth=basic,digest,negotiate,ntlm'
'--enable-basic-auth-helpers=getpwnam,LDAP,MSNT,multi-domain-NTLM,NCSA,PAM,SMB,YP,SASL,POP3,DB,squid_radius_auth'
'--enable-ntlm-auth-helpers=fakeauth,no_check,SMB'
'--enable-negotiate-auth-helpers=squid_kerb_auth'
'--enable-digest-auth-helpers=password,ldap,eDirectory'
'--enable-external-acl-helpers=ip_user,ldap_group,session,unix_group,wbinfo_group'
'--with-default-user=squid' '--with-pthreads' '--with-dl'
'--with-openssl=/usr' '--with-large-files'
'--with-build-environment=default' '--with-filedescriptors=1024'
'build_alias=x86_64-mandriva-linux-gnu' 'CFLAGS=-O2 -g -pipe -Wformat
-Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -fexceptions
-fstack-protector --param=ssp-buffer-size=4 -fstack-protector-all
-D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64' 'LDFLAGS= -Wl,--as-needed
-Wl,--no-undefined -Wl,-z,relro' 'CPPFLAGS=-I/usr/include/openssl '
'CXXFLAGS=-O2 -g -pipe -Wformat -Werror=format-security
-Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector
--param=ssp-buffer-size=4 -fstack-protector-all -D_LARGEFILE64_SOURCE
-D_FILE_OFFSET_BITS=64'



A keytab file was create on AD for squid
(HTTP/fqdn at REALM)

ktpass -princ HTTP/fqdn at REALM -mapuser squiduser
-pass password -ptype KRB5_NT_SRV_HST -out HTTP.keytab

Transferred the file to the squid server and placed it
in /etc/squid/HTTP.keytab


kinit -k -t /etc/squid/HTTP.keytab HTTP/fqdn at REALM
it works!


At /etc/init.d/squid, I have included:
KRB5_KTNAME=/etc/squid/HTTP.keytab
export KRB5_KTNAME

I have configured /etc/squid/squid.conf to use squid_kerb_auth

I am using IE as client and  set the proxy to fqdn.

When i try to go to http://www.squid-cache.org/, IE asks for login and
password, but it fails.
The messages between squid an IE are:

IE -> SQUID
GET http://www.squid-cache.org/ HTTP/1.1
[...]

SQUID -> IE
HTTP/1.0 407 Proxy Authentication Required
Server: squid/3.0.STABLE14
[...]
Proxy-Authenticate: Negotiate
[...]

IE -> SQUID
GET http://www.squid-cache.org/ HTTP/1.1
[...]
Proxy-Authorization: Negotiate
TlRMTVNTUAABAAAAB4IIogAAAAAAAAAAAAAAAAAAAAAFASgKAAAADw==

SQUID -> IE
HTTP/1.0 407 Proxy Authentication Required
Server: squid/3.0.STABLE14
[...]
Proxy-Authenticate: Negotiate
[...]

Seems like IE tries to authenticate with NTLM, and not with kerberos.

How do I sort out this problem?


Thanks in advance.
Regards
Jose Lopes