Troubleshooting Certmonger issues with FreeIPA

In a previous post I explained the basics for certmonger. This post will focus on troubleshooting the issues that certmonger can have with FreeIPA deployments.

Certificate Authorities used by FreeIPA

When certmonger is installed on a machine, it comes with pre-defined Certificate Authorities (that can be listed using certmonger list-cas): SelfSign, IPA, certmaster, and local.

The installation of FreeIPA configures additional Certificate Authorities: dogtag-ipa-renew-agent and dogtag-ipa-ca-renew-agent. FreeIPA is using 3 of those CAs for its certificates:

  • IPA
  • dogtag-ipa-renew-agent
  • dogtag-ipa-ca-renew-agent

The table below summarizes the tracked certificates and their associated CA:

Certificate nickname Location CA Purpose
auditSigningCert cert-pki-ca /etc/pki/pki-tomcat/alias dogtag-ipa-ca-renew-agent PKI
ocspSigningCert cert-pki-ca /etc/pki/pki-tomcat/alias dogtag-ipa-ca-renew-agent PKI
subsystemCert cert-pki-ca /etc/pki/pki-tomcat/alias dogtag-ipa-ca-renew-agent PKI
caSigningCert cert-pki-ca /etc/pki/pki-tomcat/alias dogtag-ipa-ca-renew-agent PKI Certificate Authority
Server-Cert cert-pki-ca /etc/pki/pki-tomcat/alias dogtag-ipa-renew-agent (IPA < 4.5)
dogtag-ipa-ca-renew-agent (IPA 4.5+)
PKI Server
ipaCert /etc/httpd/alias (IPA < 4.5)
/var/lib.ipa/ra-agent.{key|pem}
dogtag-ipa-ca-renew-agent Renew Agent – authenticates renewal requests
Server-Cert /etc/httpd/alias IPA HTTPd server
Server-Cert /etc/dirsrv/slapd-DOMAIN-COM IPA LDAP server

Note: all the certificates tracked by dogtag-ipa-ca-renew-agent are identical on all the replicas. This means for instance that when ‘ocspSigningCert cert-pki-ca’ is renewed on the master, the new certificate must also be installed on the replicas.

The behavior is different for the Server-Cert certificates (for PKI, HTTPd and LDAP servers): each replica has its own certificate, which contains the hostname in its subject.

Potential issues with dogtag-ipa-ca-renew-agent helper

As stated in the previous post, it is possible to check the status of a certificate using getcert list. When each certificate is valid and properly tracked, the output should display status: MONITORING. If it is not the case, you may see an additional error message:

$ getcert list -n ipaCert
Number of certificates and requests being tracked: 10.
Request ID '20161214165502':
 status: CA_UNREACHABLE
 ca-error: Error 7 connecting to http://ipaserver.domain.com:8080/ca/ee/ca/profileSubmit: Couldn't connect to server.

So let’s try to understand what is happening. The helper dogtag-ipa-ca-renew-agent has a different behavior, whether it is running on the renewal master or not.

On the renewal master

Under normal circumstances, the helper dogtag-ipa-ca-renew-agent is contacting Dogtag server through http or https, issues the renewal command and then puts the new certificate in LDAP so that they can be retrieved by other replicas . Several issues can happen:

  • Dogtag server may be down. Easy to check with
    $ systemctl status pki-tomcatd@pki-tomcat.service
  • When renewing a certificate, the helper needs to authenticate through SSL. In order to do that, it uses the ipaCert certificate stored in /etc/httpd/alias and needs to read the PIN in /etc/httpd/alias/pwdfile.txt. You can check that the certificate is present and the PIN is up-to-date with
    $ certutil -L -d /etc/httpd/alias/ -n ipaCert
    $ certutil -K -d /etc/httpd/alias/ -f /etc/httpd/alias/pwdfile.txt
  • The helper needs to trust IPA CA in order to establish a SSL connection to Dogtag server. It is using /etc/ipa/ca.crt as certificate trust anchor. Check that this file is up-to-date.
  • When the certificate is renewed, the helper puts the certificate in LDAP below cn=nickname,cn=ca_renewal,cn=ipa,cn=etc,$BASEDN.

In order to find which step failed, you can first examine the journal:

$ journalctl -u certmonger --since today
[...] dogtag-ipa-ca-renew-agent-submit[14237]: Forwarding request to dogtag-ipa-renew-agent
[...] dogtag-ipa-ca-renew-agent-submit[14237]: dogtag-ipa-renew-agent returned 3
[...] certmonger[69651]: 2016-12-19 11:19:02 [69651] Error 7 connecting to http://ipaserver.domain.com:8080/ca/ee/ca/profileSubmit: Couldn't connect to server.

You can see that the request is forwarded to another helper (dogtag-ipa-renew-agent) and the logs display the result code returned by this other helper. The result codes are defined in certmonger API:

  • 0: certificate issued, success
  • 1: the client should wait. The helper outputs a cookie value that will be reused in the next call.
  • 2: request rejected
  • 3: error connecting to the CA
  • 4: the helper requires additional configuration data
  • 5: the client should wait. The helper outputs a delay and a cookie.
  • 6: the CA does not understand the request
  • 16: the helper needs SCEP data
  • 17: the client needs to try again using a different key pair

The log also displays when the pre-save and post-save commands are called, and finally the success of the operation.

When the operation fails, you can increase the debug level to get more information: edit (or create) /etc/ipa/server.conf and add the following:

[global]
debug = True

and modify the helper to put it in debug mode with the -vv option:

$ getcert modify-ca -c dogtag-ipa-ca-renew-agent -e '/usr/libexec/certmonger/dogtag-ipa-ca-renew-agent-submit -vv'

At this point, the helper will log information in /var/log/ipa/renew.log that may help diagnose the issue:

[...] ipa DEBUG Starting external process
[...] ipa DEBUG args=/usr/libexec/certmonger/dogtag-ipa-renew-agent-submit -vv --submit-option requestor_name=IPA
[...] ipa DEBUG Process finished, return code=3
[...] ipa DEBUG stdout=Error 7 connecting to http://ipaserver.domain.com:8080/ca/ee/ca/profileSubmit: Couldn't connect to server.

[...] ipa DEBUG stderr=* Trying 2620:52:0:224e:21a:4aff:fe23:14c7...
* connect to 2620:52:0:224e:21a:4aff:fe23:14c7 port 8080 failed: Connection refused
* Trying 10.34.58.51...
* connect to 10.34.58.51 port 8080 failed: Connection refused
* Failed to connect to ipaserver.domain.com port 8080: Connection refused
* Closing connection 0
GET "http://ipaserver.domain.com:8080/ca/ee/ca/profileSubmit?profileId=caServerCert&serial_num=14&renewal=true&xml=true&requestor_name=IPA"
code = 7
code_text = "Couldn't connect to server"
results = "(null)"

In this case the issue was simply that pki server was stopped. The solution was to restart and resubmit the certificate request.

 

On non-renewal master

The helper has a different behavior when it does not run on the renewal master. It connects to the local LDAP server and reads the renewed certificate below cn=nickname,cn=ca_renewal,cn=ipa,cn=etc,$BASEDN, then copies the certificate into the right location. It is easy to check the access log of the directory server and make sure that the LDAP search succeeded (/var/log/dirsrv/slapd-DOMAIN-COM/access):

[...] conn=1274 op=1 SRCH base="cn=subsystemCert cert-pki-ca,cn=ca_renewal,cn=ipa,cn=etc,dc=domain,dc=com" scope=0 filter="(objectClass=*)" attrs="userCertificate"
[...] conn=1274 op=1 RESULT err=0 tag=101 nentries=1 etime=0

In this log we can see that the renewed certificate ‘subsystemCert cert-pki-ca’ was found (nentries=1).

The certificate is not found if:

  • there are replication issues and the replica did not get cn=nickname,cn=ca_renewal,cn=ipa,cn=etc,$BASEDN updated
  • the renewal on the master did not succeed to upload the new certificate in LDAP

 

Potential issues with IPA helper

This helper is used to renew the server certificate for HTTPd, LDAP and PKI. The helper is communicating with FreeIPA server using XML-RPC (with the URI defined in /etc/ipa/default.conf as xmlrpc_uri), trusting the CA certificate in /etc/ipa/ca.crt. Note that the helper may connect to FreeIPA server running on a different host.

When FreeIPA server receives the request, it handles the operation by submitting the renewal to the PKI server through CA REST API, using the certificate ipaCert located in /etc/httpd/alias for authentication.

If the certificates are not up-to-date, the communication will fail with the following error:

Request ID '20161214165647':
 status: CA_UNREACHABLE
 ca-error: Server at https://vm-058-051.abc.idm.lab.eng.brq.redhat.com/ipa/xml failed request, will retry: 4016 (RPC failed at server. Failed to authenticate to CA REST API)

Sometimes just running $ ipa-certupdate and resubmitting the request will fix the issue. On a non-renewal master you may also need to update ipaCert using $ getcert resubmit -i requestID_for_ipaCert.

The log files that may help troubleshoot are the following:

  • /var/log/httpd/access_log and error_log: they should display the communication between the CA helper and FreeIPA server
  • /var/log/pki/pki-tomcat/ca/debug: this log will show PKI server handling the renewal requests, in multiple steps (profileSubmit, profileReview, profileProcess).
  • the journal

 

Potential issues with dogtag-ipa-renew-agent

This helper is used to renew PKI Server certificate. It is also using ipaCert to communicate with the PKI server and may fail on a replica when ipaCert is not up-to-date:

Request ID '20161219133932':
 status: MONITORING
 ca-error: Server at "https://ipareplica.domain.com:8443/ca/agent/ca/profileProcess" replied: 1: Invalid Credential.

In this case, start by renewing ipaCert. This command will download the new ipaCert from LDAP:

$ getcert list -n ipaCert | grep Request
Request ID '20161214210956':
$ getcert resubmit -i 20161214210956

When ipaCert has been updated, you can try to re-submit the request for PKI Server-Cert.

 

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