In order to take the path of moving this setting to a krb5.conf snippet
that's included by the default krb5.conf, at the very least it needs to
work with both Heimdal and MIT.  I don't think Heimdal supports
including krb5.conf snippets, which means we can't use the include
functionality in kerberos-configs.

The upgrade path for this is going to be awful no matter what.  :(

I don't think it's acceptable from a security standpoint for minimum_uid
to be turned off by an upgrade without an affirmative response from the
user (not any sort of default), and we can't use any sort of krb5-config
dependency to ensure that a Kerberos configuration fragment is available
(even if Heimdal supports it) because krb5-config intentionally doesn't
mess with a user-supplied krb5.conf file.  So we'd have to do something
really fancy here that preserves the minimum_uid setting for all old
installations unless the admin intentionally removes it, and I'm not
entirely sure how to do that.  All the approaches I can think of have
obvious ways in which the setting is lost.

Some sort of user override on the default pam-auth-update configuration
would be ideal, but I can understand that not being a priority.

I would love to find a way to fix this, but we really *cannot* have an
upgrade turn off minimum_uid without user intervention.  I think a
package that would do that would deserve a CVE due to the security
vulnerabilities that can introduce, since the local admin may be relying
on that setting for local security.

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https://bugs.launchpad.net/bugs/369575

Title:
  Why is /usr/share/pam-configs/krb5 specifying minimum_uid= ?

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