[Freeipa-users] PKINIT support in FreeIPA 4.2.0
Nik Lam
nik.eb.inc at gmail.com
Wed Feb 10 12:07:14 UTC 2016
On Wed, Feb 10, 2016 at 7:43 PM, Sumit Bose <sbose at redhat.com> wrote:
> On Wed, Feb 10, 2016 at 12:07:45PM +1100, Nik Lam wrote:
> > On Wed, Feb 10, 2016 at 3:04 AM, Sumit Bose <sbose at redhat.com> wrote:
> >
> > > On Wed, Feb 10, 2016 at 02:08:55AM +1100, Nik Lam wrote:
> > > > On Mon, Feb 8, 2016 at 11:53 PM, Sumit Bose <sbose at redhat.com>
> wrote:
> > > >
> > > > > On Thu, Feb 04, 2016 at 07:25:29PM +1100, Nik Lam wrote:
> > > > > > On Wed, Feb 3, 2016 at 8:08 PM, Sumit Bose <sbose at redhat.com>
> wrote:
> > > > > >
> > > > > > > On Wed, Feb 03, 2016 at 10:29:49AM +1100, Nik Lam wrote:
> > > > > > > > Hello,
> > > > > > > >
> > > > > > > > I installed ipa-server on Centos 7.1 and later did and
> upgrade
> > > of the
> > > > > > > whole
> > > > > > > > system to Centos 7.2.
> > > > > > > >
> > > > > > > > I think the FreeIPA version changed from 4.1.0 to 4.2.0
> between
> > > these
> > > > > > > > Centos/RHEL minor releases.
> > > > > > > >
> > > > > > > > We'd now like to try integrating with a 2FA provider via a
> radius
> > > > > proxy
> > > > > > > and
> > > > > > > > want to use anonymous PKINIT to secure the initial
> communications
> > > > > between
> > > > > > > > the client and the KDC.
> > > > > > > >
> > > > > > > > We've tried following the MIT Kerberos PKINIT configuration
> > > > > documentation
> > > > > > > >
> > > > > > > >
> http://web.mit.edu/kerberos/krb5-1.14/doc/admin/pkinit.html
> > > > > > > >
> > > > > > > > generating our own certs manually with openssl but haven't
> had
> > > any
> > > > > luck.
> > > > > > > > We're seeing this in the kdc log:
> > > > > > > >
> > > > > > > > preauth pkinit failed to initialize: No realms configured
> > > > > correctly
> > > > > > > for
> > > > > > > > pkinit support
> > > > > > >
> > > > > > > Which changes did you apply to krb5.conf? Did you use the IPA
> CA to
> > > > > sign
> > > > > > > the certificate or some other CA?
> > > > > > >
> > > > > > > >
> > > > > > > > I've noticed there are many new pkinit-related options that
> have
> > > been
> > > > > > > added
> > > > > > > > to the ipa-server-install script in 4.2.0, so it looks like
> > > PKINIT is
> > > > > > > > available in this version of FreeIPA. Is that the case?
> > > > > > >
> > > > > > > Which options are you referring to?
> > > > > > >
> > > > > > > bye,
> > > > > > > Sumit
> > > > > > >
> > > > > > > >
> > > > > > > > And if it is, what is the recommended way to enable it given
> > > that it
> > > > > > > seems
> > > > > > > > to have been disabled in the original install that I did? Or
> > > would it
> > > > > > > just
> > > > > > > > be easier to start from scratch with a 4.2.0
> ipa-server-install?
> > > > > (It's a
> > > > > > > > test instance that doesn't have too much in it - it will
> take a
> > > > > several
> > > > > > > > hours to rebuild from scratch.)
> > > > > > > >
> > > > > > > > Regards,
> > > > > > > >
> > > > > > > > Nik
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > Thanks Sumit.
> > > > > >
> > > > > > It sounds like PKINIT is available but clearly I'm doing it
> wrong.
> > > > > >
> > > > > > > Which changes did you apply to krb5.conf? Did you use the IPA
> CA
> > > to
> > > > > sign
> > > > > > the certificate or some other CA?
> > > > > >
> > > > > > Actually, I modified the kdc.conf file - placed the kdc.pem,
> > > kdckey.pem
> > > > > and
> > > > > > cacert.pem files in /var/kerberos/krb5kdc/ that I generated via
> > > openssl
> > > > > > commands in the MIT Kerberos documentation. The only change to
> > > kdc.conf
> > > > > > file was to append the location of the kdckey.pem file to
> > > > > pkinit_identity.
> > > > > >
> > > > > > pkinit_identity = FILE:/var/kerberos/krb5kdc/kdc.pem
> > > > > > pkinit_anchors = FILE:/var/kerberos/krb5kdc/cacert.pem
> > > > > >
> > > > > > became
> > > > > >
> > > > > > pkinit_identity =
> > > > > >
> FILE:/var/kerberos/krb5kdc/kdc.pem,/var/kerberos/krb5kdc/kdckey.pem
> > > > > > pkinit_anchors = FILE:/var/kerberos/krb5kdc/cacert.pem
> > > > > >
> > > > > > Should I have been modifying krb5.conf instead? It aslo sounds
> like I
> > > > > need
> > > > >
> > > > > no, kdc.conf is the right place, I actually meant kdc.conf but
> > > > > accidentially types krb5.conf.
> > > > >
> > > > > > to use a certificate signed by the IPAs CA - is this something
> that
> > > > > should
> > > > > > be generated using ipa-getcert? Or do I just find the IPA CA's
> > > private
> > > > > key
> > > > > > and use openssl following the MIT Kerberos documentation?
> > > > > >
> > > > > > > Which options are you referring to?
> > > > > >
> > > > > > When I looked at the --help text for 4.1.0 and 4.2.0 versions of
> > > > > > ipa-server-install, I noticed that 4.2.0 has these in the
> > > "certificate
> > > > > > system options":
> > > > > >
> > > > > > --no-pkinit disables pkinit setup steps
> > > > > >
> > > > > > --pkinit-cert-file=FILE
> > > > > > File containing the Kerberos KDC SSL
> > > certificate
> > > > > and
> > > > > > private key
> > > > > >
> > > > > > --pkinit-pin=PIN The password to unlock the Kerberos KDC
> > > private
> > > > > key
> > > > > >
> > > > > > --pkinit-cert-name=NAME
> > > > > > Name of the Kerberos KDC SSL certificate
> to
> > > > > install
> > > > > >
> > > > > >
> > > > > > Seeing that first one, I was a little hopeful that pkinit is
> enabled
> > > by
> > > > > > default in 4.2.0 but on a fresh install I just tried, I'm still
> > > seeing
> > > > > the
> > > > >
> > > > > no, unfortunately pkinit is currently disabled by default
> > > > >
> > > > > > following in krb5kdc.log when IPA is started up, so clearly it
> isn't.
> > > > > >
> > > > > > (Error): preauth pkinit failed to initialize: No realms
> configured
> > > > > > correctly for pkinit support
> > > > >
> > > > > I get the same error when I put the certificate and the key into
> > > > > separate files. Can you try to put both into one and use this for
> the
> > > > > pkinit_identity option?
> > > > >
> > > > > HTH
> > > > >
> > > > > bye,
> > > > > Sumit
> > > > >
> > > >
> > > >
> > > > Thanks Sumit, it did!
> > > >
> > > > I concatenated the cert and the key into a single file and the error
> has
> > > > indeed gone away from krb5kdc.log
> > > >
> > > > The odd thing is that I can't reproduce the error by splitting into
> two
> > > > separate files and restarting ipa.service again.
> > > >
> > > > Ignoring that mystery, how do I go about setting up the
> > > WELLKNOWN/ANONYMOUS
> > > > principal?
> > > >
> > > > I'm pretty sure it's needed for anonymous pkinit:
> > > >
> > > > $ kinit
> > > > kinit: Generic preauthentication failure while getting initial
> > > credentials
> > > > $
> > > >
> > > > $ kinit -n
> > > > kinit: Client 'WELLKNOWN/ANONYMOUS at EXAMPLE.COM' not found in
> Kerberos
> > > > database while getting initial credentials
> > > > $
> > > >
> > > > Using kadmin per the MIT documentation doesn't seem to work
> > > (authenticated
> > > > as an IPA admin)
> > > >
> > > > # kadmin -q 'addprinc -randkey WELLKNOWN/ANONYMOUS'
> > > > Authenticating as principal admin/admin at EXAMPLE.COM with password.
> > > > kadmin: Client not found in Kerberos database while initializing
> kadmin
> > > > interface
> > > > #
> > > >
> > > > # kadmin -q 'addprinc -randkey WELLKNOWN/ANONYMOUS' -p admin
> > > > Authenticating as principal admin with password.
> > > > Password for admin at EXAMPLE.COM:
> > > > WARNING: no policy specified for WELLKNOWN/ANONYMOUS at EXAMPLE.COM;
> > > > defaulting to no policy
> > > > add_principal: Operation requires ``add'' privilege while creating
> > > > "WELLKNOWN/ANONYMOUS at EXAMPLE.COM".
> > > > #
> > >
> > > Please try
> > >
> > > kadmin.local -x ipa-setup-override-restrictions
> > >
> > > bye,
> > > Sumit
> > >
> > >
> > Thanks Sumit.
> >
> > That seems to have worked to get the principal created.
> >
> > # kadmin.local -x ipa-setup-override-restrictions
> > Authenticating as principal admin/admin at EXAMPLE.COM with password.
> > kadmin.local: addprinc -randkey WELLKNOWN/ANONYMOUS
> > WARNING: no policy specified for WELLKNOWN/ANONYMOUS at EXAMPLE.COM;
> > defaulting to no policy
> > Principal "WELLKNOWN/ANONYMOUS at EXAMPLE.COM" created.
> > kadmin.local: quit
> > #
> >
> > I'm no longer seeing the error from the client about 'WELLKNOWN/
> > ANONYMOUS at EXAMPLE.COM' not found in Kerberos database.
> >
> > However, I'm being prompted for a password for the anonymous principal.
> >
> > $ kinit -n
> > Password for WELLKNOWN/ANONYMOUS at EXAMPLE.COM:
> > kinit: Password incorrect while getting initial credentials
> > $
> >
> > That doesn't sound right to me - and indeed it doesn't provide an armor
> > cache that I can use for authenticating my client user.
>
> Can you run
>
> KRB5_TRACE=/dev/stdout kinit -n
>
> this will show the list of preauthentication methods offered to the
> client and I would suspect that pkinit is not among of them.
>
> My guess is that there is something wrong with the certificate or the
> configuration, e.g. did you try to set pkinit_kdc_hostname to the
> hostname matching the one in the KDC certificate? Maybe
> pkinit_eku_checking = none might help as well?.
>
> To analyse this further the most easy way is an instrumented build of
> the pkinit module with debugging enabled. If you can tell me the exact
> version of your krb5-pkinit package I can prepare a build for you.
>
> HTH
>
> bye,
> Sumit
>
Thank you Sumit.
I've checked that the hostname in the KDC's cert matches what I've put in
the client's krb.conf's pkinit_hostname.
I've also tried setting pkinit_eku_checking = none in there.
$ KRB5_TRACE=/dev/stdout kinit -n
[9199] 1455105392.574916: Getting initial credentials for WELLKNOWN/
ANONYMOUS at EXAMPLE.COM
[9199] 1455105392.575132: Sending request (186 bytes) to EXAMPLE.COM
[9199] 1455105392.575314: Initiating TCP connection to stream
10.93.178.73:88
[9199] 1455105392.576513: Sending TCP request to stream 10.93.178.73:88
[9199] 1455105393.370873: Received answer (483 bytes) from stream
10.93.178.73:88
[9199] 1455105393.370885: Terminating TCP connection to stream
10.93.178.73:88
[9199] 1455105393.370956: Response was from master KDC
[9199] 1455105393.370977: Received error from KDC: -1765328359/Additional
pre-authentication required
[9199] 1455105393.371014: Processing preauth types: 16, 15, 14, 136, 19,
147, 2, 133
[9199] 1455105393.371040: Selected etype info: etype aes256-cts, salt
"EXAMPLE.COMWELLKNOWNANONYMOUS", params ""
[9199] 1455105393.371046: Received cookie: MIT
Password for WELLKNOWN/ANONYMOUS at EXAMPLE.COM:
[9199] 1455105400.912468: AS key obtained for encrypted timestamp:
aes256-cts/09BF
[9199] 1455105400.912546: Encrypted timestamp (for 1455105400.914484):
plain 301AA011180F32303136303231303131353634305AA10502030DF434, encrypted
DD840BC3D6F697529D987E73EDD1C9FF82FEC91A0FB408179E6FA9AF49627912BEF49BA4E4EE8FF469BED5672943592A1E7DFBBF781C1E5B
[9199] 1455105400.912576: Preauth module encrypted_timestamp (2) (real)
returned: 0/Success
[9199] 1455105400.912581: Produced preauth for next request: 133, 2
[9199] 1455105400.912601: Sending request (281 bytes) to EXAMPLE.COM
[9199] 1455105400.912674: Initiating TCP connection to stream
10.93.178.73:88
[9199] 1455105400.913894: Sending TCP request to stream 10.93.178.73:88
[9199] 1455105400.937778: Received answer (197 bytes) from stream
10.93.178.73:88
[9199] 1455105400.937788: Terminating TCP connection to stream
10.93.178.73:88
[9199] 1455105400.937835: Response was from master KDC
[9199] 1455105400.937852: Received error from KDC: -1765328353/Decrypt
integrity check failed
kinit: Password incorrect while getting initial credentials
$
The module package we're using right now is
krb5-pkinit-1.13.2-10.el7.x86_64.
Regards,
Nik
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