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Created attachment 1153561[details]
Patch to enable use of dns_canonicalize_hostname flag in krb5.conf, disables if set to 0
Description of problem:
Hostnames pointing to CNAMEs for server principals validates against the target of the CNAME instead of the given server principal/hostname.
Version-Release number of selected component (if applicable):
1.10.3-42z1
How reproducible:
Always.
Use a binary or script that can complete Kerberos authentication against a URL -- for example, curl -- using krb5-libs.
Reproduction using the below method requires a working Kerberos system with a REST URL endpoint that supports authenticating with a Kerberos ticket.
Where x.a_real_url.com is a CNAME that points to y.a_real_url.com:
Steps to Reproduce:
1. curl -u : --negotiate -vi -H 'Content-Type:application/json' -X POST -d '{"json": [{"pay": "load"}], "message": ""}' https://x.a_real_url.com
2. Part of the return will contain: Server HTTP/y.a_real_url.com@REALM not found in Kerberos database
Actual results:
Server HTTP/y.a_real_url.com@REALM not found in Kerberos database
Expected results:
Server principal checked is x.a_real_url.com.
This bug has been cross-reported to the CentOS 6 bug tracker as well as krb5 github:
- https://bugs.centos.org/view.php?id=10775
- https://github.com/krb5/krb5/pull/443#event-649100795
A colleague recommended I report it here, too.
Expected results:
Additional info:
(In reply to Mark Shields from comment #3)
> Thank you! Do you have an ETA for the next CentOS 6.x release?
CentOS as I understand it will release at about the same time RHEL releases; I don't believe it's publicly decided when that will be, but you can get a good idea of the timeframe we're talking about from wikipedia: https://en.wikipedia.org/wiki/Red_hat_enterprise_linux#Version_history We are too late to make 6.8, but I'm targeting 6.9.
Unfortunately, I'm not strongly involved in the CentOS process itself. If this were a Fedora bug I could fix it instanter, but RHEL is slower-moving than that.
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.
https://rhn.redhat.com/errata/RHBA-2017-0643.html