James A. Peltier
2010-Jul-02 18:27 UTC
[CentOS] Windows 2003 AD, Winbind, Kerberos and NFSv4
Hi All,
I'm having a bit of difficulty getting a CentOS 5.5 Kerberized NFSv4
server working. This server is configured as a Winbind client to a
Windows 2003 Active Directory. I've successfully bound it to AD and I am
able to authenticate. I've successfully created a NFSv4 entry in
/etc/exports to export the /exports directory and I can successfully mount
a non-Kerberized NFSv4 mount on a client machine. I now want to take it
to the next step and add Kerberos and it doesn't seem to be working for
me. Below are my configurations and the steps I performed.
Fresh install of CentOS 5.5. Non-Kickstarted. Wanted to get it working
manually first.
Used the First Boot Authentication Wizard to configure Winbind Support for
User Information.
Configured Winbind and Kerberos under the Authentication Tab
Checked Local auth is sufficient and Create home directories under options
The computer successfully joins the domain and appears in the Computer
container in AD. Below is the extract from /etc/samba/smb.conf for
authconfig plus what I changed, everything else is stock.
I disabled the firewall and SELinux is running in permissive mode on both
the test server and test client.
#======================= Global Settings ====================================
[global]
#--authconfig--start-line--
# Generated by authconfig on 2010/07/01 18:32:54
# DO NOT EDIT THIS SECTION (delimited by --start-line--/--end-line--)
# Any modification may be deleted or altered by authconfig in future
workgroup = MY.AD.NAME
password server = MY.AD.SERVER
realm = MY.AD.NAME
security = ads
idmap uid = 16777216-33554431
idmap gid = 16777216-33554431
template shell = /bin/bash
#--authconfig--end-line--
#-- my additions/changes-start --
template homedir = /home/%U
winbind use default domain = true
winbind offline logon = true
winbind nested groups = true
winbind refresh tickets = true
use spnego = yes
use kerberos keytab = yes
#-- my additions/changes-end --
It also created an appropriate, I believe, /etc/krb5.conf to which I
removed only the .example.com stuff resulting in the following file.
[logging]
default = FILE:/var/log/krb5libs.log
kdc = FILE:/var/log/krb5kdc.log
admin_server = FILE:/var/log/kadmind.log
[libdefaults]
default_realm = MY.AD.NAME
dns_lookup_realm = false # with and without true tried for these
dns_lookup_kdc = false
ticket_lifetime = 24h
forwardable = yes
[realms]
MY.AD.NAME = {
kdc = MY.AD.SERVER
admin_server = MY.AD.SERVER
kdc = MY.AD.SERVER
}
[domain_realm]
my.ad.name = MY.AD.NAME
.my.ad.name = MY.AD.NAME
[appdefaults]
pam = {
debug = false
ticket_lifetime = 36000
renew_lifetime = 36000
forwardable = true
krb4_convert = false
}
If I log into this host I am properly issued a Kerberos ticket from AD so
it would appear that Kerberos is working properly
[jpeltier at oak ~]$ ssh aconite klist
jpeltier at aconite's password:
klist: You have no tickets cached
Ticket cache: FILE:/tmp/krb5cc_16777216_ltvWwy
Default principal: jpeltier at MY.AD.NAME
Valid starting Expires Service principal
07/02/10 10:46:43 07/02/10 20:46:43 krbtgt/MY.AD.NAME at MY.AD.NAME
renew until 07/02/10 20:46:43
Kerberos 4 ticket cache: /tmp/tkt16777216
[jpeltier at oak ~]$
Now I configured NFSv4 exports on the server
/exports *(rw,fsid=0)
Edited /etc/sysconfig/nfs to change
# Set to turn on Secure NFS mounts.
#SECURE_NFS="yes"
to
# Set to turn on Secure NFS mounts.
SECURE_NFS="yes"
restarted NFS service and it appears as an export
[root at aconite ~]# /etc/init.d/nfs restart
Shutting down NFS mountd: [ OK ]
Shutting down NFS daemon: [ OK ]
Shutting down NFS quotas: [ OK ]
Shutting down NFS services: [ OK ]
Shutting down RPC svcgssd: [ OK ]
Starting RPC svcgssd: [ OK ]
Starting NFS services: [ OK ]
Starting NFS quotas: [ OK ]
Starting NFS daemon: [ OK ]
Starting NFS mountd: [ OK ]
[root at aconite ~]# exportfs
/exports <world>
[root at aconite ~]#
To support NFSv4 with Kerberos security, we also need to generate service
principal for NFS:
[root at aconite ~]# net -U administrator ads keytab add nfs
which then looks like this
[root at aconite ~]# klist -k
Keytab name: FILE:/etc/krb5.keytab
KVNO Principal
---- --------------------------------------------------------------------------
3 host/aconite.my.ad.name at MY.AD.NAME
3 host/aconite.my.ad.name at MY.AD.NAME
3 host/aconite.my.ad.name at MY.AD.NAME
3 host/aconite at MY.AD.NAME
3 host/aconite at MY.AD.NAME
3 host/aconite at MY.AD.NAME
3 ACONITE$@MY.AD.NAME
3 ACONITE$@MY.AD.NAME
3 ACONITE$@MY.AD.NAME
3 nfs/aconite.my.ad.name at MY.AD.NAME
3 nfs/aconite.my.ad.name at MY.AD.NAME
3 nfs/aconite.my.ad.name at MY.AD.NAME
3 nfs/aconite at MY.AD.NAME
3 nfs/aconite at MY.AD.NAME
3 nfs/aconite at MY.AD.NAME
Test on the client
[root at celastrina ~]# showmount -e aconite
Export list for aconite:
/exports *
[root at celastrina ~]# mount -t nfs4 aconite:/ /mnt
[root at celastrina ~]# mount |grep -i nfs4
aconite:/ on /mnt type nfs4 (rw,addr=199.60.1.84)
[root at celastrina ~]#
So as you can see everything is now working *without* Kerberos. However,
if I change the /etc/exports file on aconite to
[root at aconite ~]# cat /etc/exports
/exports gss/krb5(rw,fsid=0)
[root at aconite ~]# exportfs
/exports gss/krb5
and then try to mount with the -o sec=krb5 on the client
[root at celastrina ~]# mount -t nfs4 -o sec=krb5 aconite:/ /mnt
mount.nfs4: Permission denied
and the entry in /var/log/messages on celastrina is
Jul 2 11:21:57 celastrina rpc.gssd[3302]: Using keytab file
'/etc/krb5.keytab'
Jul 2 11:21:57 celastrina rpc.gssd[3302]: WARNING: Failed to obtain
machine credentials for connection to server aconite.my.ad.name
nothing appears in the logs on aconite.
If you've been kind enough to read this entire thread could you be kind
enough to let me know what I am missing or doing wrong? It seems so close
now that I can taste it, but this one last piece doesn't seem to want to
fall into place. :(
--
James A. Peltier
Systems Analyst (FASNet), VIVARIUM Technical Director
HPC Coordinator
Simon Fraser University - Burnaby Campus
Phone : 778-782-6573
Fax : 778-782-3045
E-Mail : jpeltier at sfu.ca
Website : http://www.fas.sfu.ca | http://vivarium.cs.sfu.ca
http://blogs.sfu.ca/people/jpeltier
MSN : subatomic_spam at hotmail.com
TEAMWORK
There's power in numbers. Learn to work together.
Louis Lagendijk
2010-Jul-02 20:50 UTC
[CentOS] Windows 2003 AD, Winbind, Kerberos and NFSv4
On Fri, 2010-07-02 at 11:27 -0700, James A. Peltier wrote:> Hi All,> To support NFSv4 with Kerberos security, we also need to generate service > principal for NFS: > > [root at aconite ~]# net -U administrator ads keytab add nfs > > which then looks like this > > [root at aconite ~]# klist -k > Keytab name: FILE:/etc/krb5.keytab > KVNO Principal > ---- -------------------------------------------------------------------------- > 3 host/aconite.my.ad.name at MY.AD.NAME > 3 host/aconite.my.ad.name at MY.AD.NAME > 3 host/aconite.my.ad.name at MY.AD.NAME > 3 host/aconite at MY.AD.NAME > 3 host/aconite at MY.AD.NAME > 3 host/aconite at MY.AD.NAME > 3 ACONITE$@MY.AD.NAME > 3 ACONITE$@MY.AD.NAME > 3 ACONITE$@MY.AD.NAME > 3 nfs/aconite.my.ad.name at MY.AD.NAME > 3 nfs/aconite.my.ad.name at MY.AD.NAME > 3 nfs/aconite.my.ad.name at MY.AD.NAME > 3 nfs/aconite at MY.AD.NAME > 3 nfs/aconite at MY.AD.NAME > 3 nfs/aconite at MY.AD.NAME >did you create the keytab on the CLIENT also?> > Test on the client > > [root at celastrina ~]# showmount -e aconite > Export list for aconite: > /exports * > [root at celastrina ~]# mount -t nfs4 aconite:/ /mnt > [root at celastrina ~]# mount |grep -i nfs4 > aconite:/ on /mnt type nfs4 (rw,addr=199.60.1.84) > [root at celastrina ~]# > > So as you can see everything is now working *without* Kerberos. However, > if I change the /etc/exports file on aconite to > > [root at aconite ~]# cat /etc/exports > /exports gss/krb5(rw,fsid=0) > [root at aconite ~]# exportfs > /exports gss/krb5 > > > and then try to mount with the -o sec=krb5 on the client >is rpc.gssd running on the client? rpc.svc.gssd on the server?> [root at celastrina ~]# mount -t nfs4 -o sec=krb5 aconite:/ /mnt > mount.nfs4: Permission denied > > and the entry in /var/log/messages on celastrina is > > Jul 2 11:21:57 celastrina rpc.gssd[3302]: Using keytab file > '/etc/krb5.keytab' > Jul 2 11:21:57 celastrina rpc.gssd[3302]: WARNING: Failed to obtain > machine credentials for connection to server aconite.my.ad.name > > nothing appears in the logs on aconite. >so you most likely do not have a keytab on the client. Using kerberos is not simple.... Louis
James A. Peltier
2010-Jul-03 01:19 UTC
[CentOS] Windows 2003 AD, Winbind, Kerberos and NFSv4
On Fri, 2 Jul 2010, James A. Peltier wrote:> Hi All, > > I'm having a bit of difficulty getting a CentOS 5.5 Kerberized NFSv4 > server working. This server is configured as a Winbind client to a > Windows 2003 Active Directory. I've successfully bound it to AD and I am > able to authenticate. I've successfully created a NFSv4 entry in > /etc/exports to export the /exports directory and I can successfully mount > a non-Kerberized NFSv4 mount on a client machine. I now want to take it > to the next step and add Kerberos and it doesn't seem to be working for > me. Below are my configurations and the steps I performed. > > Fresh install of CentOS 5.5. Non-Kickstarted. Wanted to get it working > manually first. > > > Used the First Boot Authentication Wizard to configure Winbind Support for > User Information. > > Configured Winbind and Kerberos under the Authentication Tab > > Checked Local auth is sufficient and Create home directories under options > > The computer successfully joins the domain and appears in the Computer > container in AD. Below is the extract from /etc/samba/smb.conf for > authconfig plus what I changed, everything else is stock. > > I disabled the firewall and SELinux is running in permissive mode on both > the test server and test client. > > #======================= Global Settings ====================================> > [global] > #--authconfig--start-line-- > > # Generated by authconfig on 2010/07/01 18:32:54 > # DO NOT EDIT THIS SECTION (delimited by --start-line--/--end-line--) > # Any modification may be deleted or altered by authconfig in future > > workgroup = MY.AD.NAME > password server = MY.AD.SERVER > realm = MY.AD.NAME > security = ads > idmap uid = 16777216-33554431 > idmap gid = 16777216-33554431 > template shell = /bin/bash > > #--authconfig--end-line-- > > #-- my additions/changes-start -- > template homedir = /home/%U > winbind use default domain = true > winbind offline logon = true > winbind nested groups = true > winbind refresh tickets = true > use spnego = yes > use kerberos keytab = yes > #-- my additions/changes-end -- > > It also created an appropriate, I believe, /etc/krb5.conf to which I > removed only the .example.com stuff resulting in the following file. > > [logging] > default = FILE:/var/log/krb5libs.log > kdc = FILE:/var/log/krb5kdc.log > admin_server = FILE:/var/log/kadmind.log > > [libdefaults] > default_realm = MY.AD.NAME > dns_lookup_realm = false # with and without true tried for these > dns_lookup_kdc = false > ticket_lifetime = 24h > forwardable = yes > > [realms] > MY.AD.NAME = { > kdc = MY.AD.SERVER > admin_server = MY.AD.SERVER > kdc = MY.AD.SERVER > } > > [domain_realm] > my.ad.name = MY.AD.NAME > .my.ad.name = MY.AD.NAME > [appdefaults] > pam = { > debug = false > ticket_lifetime = 36000 > renew_lifetime = 36000 > forwardable = true > krb4_convert = false > } > > If I log into this host I am properly issued a Kerberos ticket from AD so > it would appear that Kerberos is working properly > > [jpeltier at oak ~]$ ssh aconite klist > jpeltier at aconite's password: > klist: You have no tickets cached > Ticket cache: FILE:/tmp/krb5cc_16777216_ltvWwy > Default principal: jpeltier at MY.AD.NAME > > Valid starting Expires Service principal > 07/02/10 10:46:43 07/02/10 20:46:43 krbtgt/MY.AD.NAME at MY.AD.NAME > renew until 07/02/10 20:46:43 > > > Kerberos 4 ticket cache: /tmp/tkt16777216 > [jpeltier at oak ~]$ > > > Now I configured NFSv4 exports on the server > > /exports *(rw,fsid=0) > > Edited /etc/sysconfig/nfs to change > > # Set to turn on Secure NFS mounts. > #SECURE_NFS="yes" > > to > > # Set to turn on Secure NFS mounts. > SECURE_NFS="yes" > > restarted NFS service and it appears as an export > > [root at aconite ~]# /etc/init.d/nfs restart > Shutting down NFS mountd: [ OK ] > Shutting down NFS daemon: [ OK ] > Shutting down NFS quotas: [ OK ] > Shutting down NFS services: [ OK ] > Shutting down RPC svcgssd: [ OK ] > Starting RPC svcgssd: [ OK ] > Starting NFS services: [ OK ] > Starting NFS quotas: [ OK ] > Starting NFS daemon: [ OK ] > Starting NFS mountd: [ OK ] > > [root at aconite ~]# exportfs > /exports <world> > [root at aconite ~]# > > To support NFSv4 with Kerberos security, we also need to generate service > principal for NFS: > > [root at aconite ~]# net -U administrator ads keytab add nfs > > which then looks like this > > [root at aconite ~]# klist -k > Keytab name: FILE:/etc/krb5.keytab > KVNO Principal > ---- -------------------------------------------------------------------------- > 3 host/aconite.my.ad.name at MY.AD.NAME > 3 host/aconite.my.ad.name at MY.AD.NAME > 3 host/aconite.my.ad.name at MY.AD.NAME > 3 host/aconite at MY.AD.NAME > 3 host/aconite at MY.AD.NAME > 3 host/aconite at MY.AD.NAME > 3 ACONITE$@MY.AD.NAME > 3 ACONITE$@MY.AD.NAME > 3 ACONITE$@MY.AD.NAME > 3 nfs/aconite.my.ad.name at MY.AD.NAME > 3 nfs/aconite.my.ad.name at MY.AD.NAME > 3 nfs/aconite.my.ad.name at MY.AD.NAME > 3 nfs/aconite at MY.AD.NAME > 3 nfs/aconite at MY.AD.NAME > 3 nfs/aconite at MY.AD.NAME > > > Test on the client > > [root at celastrina ~]# showmount -e aconite > Export list for aconite: > /exports * > [root at celastrina ~]# mount -t nfs4 aconite:/ /mnt > [root at celastrina ~]# mount |grep -i nfs4 > aconite:/ on /mnt type nfs4 (rw,addr=199.60.1.84) > [root at celastrina ~]# > > So as you can see everything is now working *without* Kerberos. However, > if I change the /etc/exports file on aconite to > > [root at aconite ~]# cat /etc/exports > /exports gss/krb5(rw,fsid=0) > [root at aconite ~]# exportfs > /exports gss/krb5 > > > and then try to mount with the -o sec=krb5 on the client > > [root at celastrina ~]# mount -t nfs4 -o sec=krb5 aconite:/ /mnt > mount.nfs4: Permission denied > > and the entry in /var/log/messages on celastrina is > > Jul 2 11:21:57 celastrina rpc.gssd[3302]: Using keytab file > '/etc/krb5.keytab' > Jul 2 11:21:57 celastrina rpc.gssd[3302]: WARNING: Failed to obtain > machine credentials for connection to server aconite.my.ad.name > > nothing appears in the logs on aconite. > > If you've been kind enough to read this entire thread could you be kind > enough to let me know what I am missing or doing wrong? It seems so close > now that I can taste it, but this one last piece doesn't seem to want to > fall into place. :(Hi All, I was able to solve this one and of course, it turned out to be quite simple once I knew what to look for. In order to get it to work I needed to alter the initial join of the host to AD. Newer versions of samba support the option createupn In previous versions of Samba and AD you had to do this process manually in AD to map the server to a userPrincipleName. Using the command net ads join createupn=nfs/`hostname`@<DOMAIN> -U <AD Admin User Name> followed by net ads keytab add nfs -U <AD Admin User Name> created all the appropriate info in AD and the /etc/krb5.keytab file in order to allow the client to mount the share via NFSv4 and krb5p extensions. -bash-3.2$ mount |grep nfs4 aconite:/ on /home type nfs4 (rw,sec=krb5p,addr=199.60.1.84) I hope this is useful to people who are trying to perform a similar operation. ;) -- James A. Peltier Systems Analyst (FASNet), VIVARIUM Technical Director HPC Coordinator Simon Fraser University - Burnaby Campus Phone : 778-782-6573 Fax : 778-782-3045 E-Mail : jpeltier at sfu.ca Website : http://www.fas.sfu.ca | http://vivarium.cs.sfu.ca http://blogs.sfu.ca/people/jpeltier MSN : subatomic_spam at hotmail.com TEAMWORK There's power in numbers. Learn to work together.