Bug 1867719 - NFSv4.0 mount using unqualified server hostname sometimes does not work
Summary: NFSv4.0 mount using unqualified server hostname sometimes does not work
Keywords:
Status: CLOSED EOL
Alias: None
Product: Fedora
Classification: Fedora
Component: nfs-utils
Version: 32
Hardware: All
OS: Linux
unspecified
medium
Target Milestone: ---
Assignee: Steve Dickson
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2020-08-10 15:25 UTC by Chuck Lever
Modified: 2021-05-25 17:46 UTC (History)
3 users (show)

Fixed In Version:
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Clone Of:
Environment:
Last Closed: 2021-05-25 17:46:53 UTC
Type: Bug
Embargoed:


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Description Chuck Lever 2020-08-10 15:25:20 UTC
Description of problem:
When the NFS server and client are both configured with a Kerberos keytab, NFS operation eventually hangs when the specified server hostname is not fully-qualified. This is because the GSS acceptor is the unqualified server hostname, but the server callback uses a service principal with the fully qualified server hostname. The mismatch causes an "invalid callback credential" message to appear in the client's log.


Version-Release number of selected component (if applicable):
Fedora's stock 5.7 kernel and upstream 5.8-rc5
nfs-utils-1:2.5.1-1.rc3.fc32.x86_64
krb5-workstation-1.18.2-10.fc32.x86_64

How reproducible:
100%


Expected results:
Previous to Fedora 32, specifying a non-fully-qualified server hostname at mount time worked properly for all NFS versions and security flavors.


Additional info:
We suspect the new default dns_canonicalize_hostname setting of "fallback" is the change that resulted in this regression. I've filed this bug under "nfs-utils" because a fix for this regression will likely have to happen in nfs-utils.

Workarounds include:
* Editing /etc/nfs.conf and setting "avoid-dns = 0"
* Editing /etc/krb5.conf and setting "dns_canonicalize_hostname = true"
* Using NFSv4.1 or newer
* Using a fully-qualified server hostname on the mount

Comment 1 Fedora Program Management 2021-04-29 17:05:27 UTC
This message is a reminder that Fedora 32 is nearing its end of life.
Fedora will stop maintaining and issuing updates for Fedora 32 on 2021-05-25.
It is Fedora's policy to close all bug reports from releases that are no longer
maintained. At that time this bug will be closed as EOL if it remains open with a
Fedora 'version' of '32'.

Package Maintainer: If you wish for this bug to remain open because you
plan to fix it in a currently maintained version, simply change the 'version' 
to a later Fedora version.

Thank you for reporting this issue and we are sorry that we were not 
able to fix it before Fedora 32 is end of life. If you would still like 
to see this bug fixed and are able to reproduce it against a later version 
of Fedora, you are encouraged  change the 'version' to a later Fedora 
version prior this bug is closed as described in the policy above.

Although we aim to fix as many bugs as possible during every release's 
lifetime, sometimes those efforts are overtaken by events. Often a 
more recent Fedora release includes newer upstream software that fixes 
bugs or makes them obsolete.

Comment 2 Ben Cotton 2021-05-25 17:46:53 UTC
Fedora 32 changed to end-of-life (EOL) status on 2021-05-25. Fedora 32 is
no longer maintained, which means that it will not receive any further
security or bug fix updates. As a result we are closing this bug.

If you can reproduce this bug against a currently maintained version of
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