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RE: pgadmin kerberos auth propblem - Delegated credentials not supplied.

From:	Milan MOLNÁR <milan_molnar(at)tatrabanka(dot)sk>
To:	Khushboo Vashi <khushboo(dot)vashi(at)enterprisedb(dot)com>
Cc:	"pgadmin-support(at)postgresql(dot)org" <pgadmin-support(at)postgresql(dot)org>
Subject:	RE: pgadmin kerberos auth propblem - Delegated credentials not supplied.
Date:	2023-01-07 10:23:23
Message-ID:	PAXPR04MB875149472107251EA6A82C67F2F89@PAXPR04MB8751.eurprd04.prod.outlook.com
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Hello Khushboo,

thnak you for your time and advice. We had to change the concept based on your recommendation, because as I wrote, we used external kdc on linux to provide krb ticket for the service and therefore there was not any user on AD.
We created service user account on the AD (password never expire, AES 128/256 encryption), set service SPN to that user, generate keytab via ktpass command. When we use pgadmin to use this keytab and ask directly AD for kerberos ticket we ended with the error message

"ERROR pgadmin: Major (65536): An unsupported mechanism was requested, Minor (0): Unknown error"

When I tried to get ticket for the service via kinit command a can get it, but default principal is not service SPN but the windows 2000 logon name of the user of AD which is this SPN mapped to?

Do you have any idea/advice hot to solve this problem?

Logs from the container

2023-01-07 10:16:44,252: DEBUG pgadmin: Authentication initiated via source: kerberos
::ffff:10.238.6.198 - - [07/Jan/2023:10:16:44 +0000] "GET /login?next=%2Fbrowser%2F HTTP/1.1" 401 4725 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/108.0.0.0 Safari/537.36 Edg/108.0.1462.54"
2023-01-07 10:16:44,388: DEBUG pgadmin: Authentication initiated via source: kerberos
2023-01-07 10:16:44,407: ERROR pgadmin: Major (65536): An unsupported mechanism was requested, Minor (0): Unknown error
Traceback (most recent call last):
File "/pgadmin4/pgadmin/authenticate/kerberos.py", line 237, in negotiate_start
out_token = context.step(base64.b64decode(in_token))
File "/venv/lib/python3.10/site-packages/decorator.py", line 232, in fun
return caller(func, *(extras + args), **kw)
File "/venv/lib/python3.10/site-packages/gssapi/_utils.py", line 165, in check_last_err
return func(self, *args, **kwargs)
File "/venv/lib/python3.10/site-packages/decorator.py", line 232, in fun
return caller(func, *(extras + args), **kw)
File "/venv/lib/python3.10/site-packages/gssapi/_utils.py", line 131, in catch_and_return_token
return func(self, *args, **kwargs)
File "/venv/lib/python3.10/site-packages/gssapi/sec_contexts.py", line 582, in step
return self._acceptor_step(token=token or b"")
File "/venv/lib/python3.10/site-packages/gssapi/sec_contexts.py", line 590, in _acceptor_step
res = rsec_contexts.accept_sec_context(token, self._creds,
File "gssapi/raw/sec_contexts.pyx", line 270, in gssapi.raw.sec_contexts.accept_sec_context
gssapi.raw.exceptions.BadMechanismError: Major (65536): An unsupported mechanism was requested, Minor (0): Unknown error

Thank you very much for your time and investigation
Ragards
milanm
From: Khushboo Vashi <khushboo(dot)vashi(at)enterprisedb(dot)com>
Sent: Wednesday, January 4, 2023 5:43 AM
To: Milan MOLNÁR <milan_molnar(at)tatrabanka(dot)sk>
Cc: pgadmin-support(at)postgresql(dot)org
Subject: Re: pgadmin kerberos auth propblem - Delegated credentials not supplied.

[EXTERNÝ E-MAIL] Tento e-mail prichádza z prostredia mimo Tatra banka Group.

Hi,

As you are using AD, there are 2 things you need to check.

1. Configure the AD server in a way that the UPN associated with HTTP should be able to delegate the tickets to the client.
2. Your browser should be able to support the kerberos ticket negotiation and delegation.

Reference:
https://www.pgadmin.org/docs/pgadmin4/6.18/kerberos.html<https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.pgadmin.org%2Fdocs%2Fpgadmin4%2F6.18%2Fkerberos.html&data=05%7C01%7Ciskamomi%40rbinternational.onmicrosoft.com%7Cc258016e49a74e56125e08daee0e36ff%7C9b511fdaf0b143a5b06e1e720f64520a%7C0%7C0%7C638084042071648743%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=eqEPmDUZv6roU8HuuiOMSpU59YRoVRKRe7RR5YAXAhA%3D&reserved=0>
https://www.youtube.com/watch?v=EDg6I21kCak<https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DEDg6I21kCak&data=05%7C01%7Ciskamomi%40rbinternational.onmicrosoft.com%7Cc258016e49a74e56125e08daee0e36ff%7C9b511fdaf0b143a5b06e1e720f64520a%7C0%7C0%7C638084042071648743%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=bGKoK71M6Nxdqs%2BoYsW4j46L2knQXDCe6r79XaJ6QTM%3D&reserved=0>

Thanks,
Khushboo

On Tue, Jan 3, 2023 at 2:32 PM Milan MOLNÁR <milan_molnar(at)tatrabanka(dot)sk<mailto:milan_molnar(at)tatrabanka(dot)sk>> wrote:
Hello,

I have trouble to setup kerberos authetication with pgadmin. I run pgadmin in the docker container and I'd like to use SPENGO SSO to access pgadmin. Pgadmin fails to authenticate user and the error message is "'Delegated credentials not supplied." It seem, that credentials does not contain delegated part. Do you have any suggestion where is the problem with my setup? Do you use kerberos auth - pls can you share your setup or just explain it a little bit?

We have kdc servers on the linux and there is trust between active directory (we use kerberos for many other services and it is working properly). I tried to connect from the PC where I'm loggend in the AD.

Docker container
Dockerfile
FROM dpage/pgadmin4:6.17

COPY krb5.conf /etc/krb5.conf
COPY config.py /pgadmin4/config.py

config.py changed variables (we have reason why to change vars here)
AUTHENTICATION_SOURCES = ['kerberos','internal']
KRB_APP_HOST_NAME = 'fqdn of pgadmin'
KRB_KTNAME = '/var/lib/pgadmin/pgadmin.keytab'

krb5.conf
cat krb5-wsl.conf
[libdefaults]
clockskew = 18000
canonicalize = true
dns_canonicalize_hostname= false
rdns = false
default_realm = EXAMPLE.COM<https://eur03.safelinks.protection.outlook.com/?url=http%3A%2F%2Fexample.com%2F&data=05%7C01%7Ciskamomi%40rbinternational.onmicrosoft.com%7Cc258016e49a74e56125e08daee0e36ff%7C9b511fdaf0b143a5b06e1e720f64520a%7C0%7C0%7C638084042071648743%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=hGC7V72n17fKenhVXN3M2H1Q9Szilx7GjbOABRmm6mU%3D&reserved=0>
default_keytab_name=/var/lib/pgadmin/pgadmin.keytab
dns_lookup_kdc = false
#ignore_acceptor_hostname = true
proxiable = true
realm_try_domains = 1

dns_lookup_realm = false
ticket_lifetime = 86400
renew_lifetime = 604800
forwardable = true
#default_tgs_enctypes = aes256-cts-hmac-sha1-96
#default_tkt_enctypes = aes256-cts-hmac-sha1-96
permitted_enctypes = aes256-cts aes128-cts
udp_preference_limit = 1
kdc_timeout = 5000

pgadmin4/pgadmin/authenticate/kerberos.py

def negotiate_start(self, in_token):
svc_princ = gssapi.Name('HTTP(at)%s' % config.KRB_APP_HOST_NAME,
name_type=gssapi.NameType.hostbased_service)
cname = svc_princ.canonicalize(gssapi.MechType.kerberos)

try:
server_creds = gssapi.Credentials(usage='accept', name=cname)
context = gssapi.SecurityContext(creds=server_creds)
out_token = context.step(base64.b64decode(in_token))
except Exception as e:
current_app.logger.exception(e)
return False, e

if out_token and not context.complete:
return False, out_token
if context.complete:
deleg_creds = context.delegated_creds
if not hasattr(deleg_creds, 'name'):
error_msg = gettext('Delegated credentials not supplied.')
current_app.logger.error(error_msg)
return False, Exception(error_msg)
try:
...

Thank you
Regards
Milanm

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In response to

Re: pgadmin kerberos auth propblem - Delegated credentials not supplied. at 2023-01-04 04:43:09 from Khushboo Vashi

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Re: pgadmin kerberos auth propblem - Delegated credentials not supplied. at 2023-01-09 06:10:57 from Khushboo Vashi

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