This issue looks to have just bit us with 4.2.x, as well.
A network configuration error led to losing two of our four CAS servers at
a busy time of day. Some fraction of the users needed to re-login, so there
was a natural increase in LDAP pool connections. Every time the validator
ran, each connection in the pool failed validation, forcing the creation of
a new set of connections. We didn't notice this behavior earlier but, now
that we look at it, it's been there all along.
Tom.
> On Feb 13, 2017, at 2:11 AM, Ben Howell-Thomas <ben.howell-thomas@
northgateps.com> wrote:
>
> Hi,
>
> I think I may have found an issue but per guidelines posting here first.
>
> When CAS is configured to authenticate with LDAP using Direct Bind and
LDAP is locked down to not allow anonymous binds/searches or for users to
see anything other than their own entry, then we get unexpected failures
trying to log in.
>
> For wrong passwords or locked accounts, every second attempt [with a
given Ldap connection from the pool] would fail. Actually, it would also
fail for a valid account with the correct password if it was on the same
connection as a failed login attempt, and the regular connection validator
would similarly fail.
>
> What's happening in Ldaptive is as follows :
> • Before a bind attempt, a SearchValidator checks the connection
is still valid
> • To make the bind attempt,
org.ldaptive.provider.jndi.JndiConnection
sets the principal and credentials on the connection's environment variable
> • This connection is then returned to the pool, still containing
the principal and credentials from the previous attempt.
> • Before the next login/bind attempt using that connection,
SearchValidator tries to validate the connection again but fails, because
it's no longer trying with the configured cas.properties
cas.authn.ldap.bindDn property but with whatever user DN was used in the
previous step
> • Since the SearchValidator fails, the connection is closed and an
exception is returned, so CAS denies access by default (even if we should
show the Account Locked page).
> I asked the Ldaptive mailing list about this which put me on to the
org.ldaptive.pool.BindPassivator class which reconnects to LDAP with the
configured DN and credentials, effectively resetting the connection to what
it should be after each bind request. That way the connection is returned
to the pool ready to be used again.
>
> Adding the following to our version of
LdapAuthenticationConfiguration.getDirectBindAuthenticator()
implemented a BindPassivator to restore expected behaviour :
>
> /*
> * Binding (which we do both when validating connections and
authenticating users) using pooled connections is "tricky"
> * according to the Ldaptive mailing list. The connection must be
returned to the pool ready for the next connection
> * to use (ie not binded as the previous user). Set a BindPassivator to
clean the connection when it's returned to the pool.
> */
> ConnectionPool cp = pooledBindAuthenticationHandle
r.getConnectionFactory().getConnectionPool();
> BindRequest br = new BindRequest(l.getBindDn(), new Credential(l.
getBindCredential()));
> cp.setPassivator(new BindPassivator(br));
>
> Another workaround of course would be to change the LDAP configuration.
>
> thanks,
>
> Ben
>
> # ps some relevant LDAP settings for reference
> cas.authn.ldap[0].type=DIRECT
> cas.authn.ldap[0].useSsl=false
> cas.authn.ldap[0].useStartTls=false
> cas.authn.ldap[0].connectTimeout=5000
> cas.authn.ldap[0].subtreeSearch=false
> cas.authn.ldap[0].bindDn=uid=cas,ou=Administrators,dc=domain,dc=com
> cas.authn.ldap[0].bindCredential=password
> cas.authn.ldap[0].minPoolSize=3
> cas.authn.ldap[0].maxPoolSize=10
> cas.authn.ldap[0].validateOnCheckout=true
> cas.authn.ldap[0].validatePeriodically=true
> cas.authn.ldap[0].validatePeriod=600
> cas.authn.ldap[0].failFast=true
> cas.authn.ldap[0].idleTime=500
> cas.authn.ldap[0].prunePeriod=600
> cas.authn.ldap[0].blockWaitTime=5000
>
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