Bug 1165126 - dnssec-trigger: publish the list of nameservers trusted for DNSSEC validation
Summary: dnssec-trigger: publish the list of nameservers trusted for DNSSEC validation
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Fedora
Classification: Fedora
Component: dnssec-trigger
Version: 21
Hardware: Unspecified
OS: Unspecified
unspecified
high
Target Milestone: ---
Assignee: Pavel Šimerda (pavlix)
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
Depends On:
Blocks: dnssec
TreeView+ depends on / blocked
 
Reported: 2014-11-18 11:57 UTC by Pavel Šimerda (pavlix)
Modified: 2015-04-21 18:49 UTC (History)
6 users (show)

Fixed In Version: dnssec-trigger-0.12-20.fc22
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2015-03-26 22:04:26 UTC
Type: Bug
Embargoed:


Attachments (Terms of Use)
patch to use a symbolic link (2.02 KB, patch)
2014-11-18 12:01 UTC, Pavel Šimerda (pavlix)
no flags Details | Diff
updated patch (4.79 KB, patch)
2014-11-18 12:39 UTC, Pavel Šimerda (pavlix)
no flags Details | Diff

Description Pavel Šimerda (pavlix) 2014-11-18 11:57:48 UTC
Currently dnssec-trigger writes trusted validating nameservers to /etc/resolv.conf just as any other tool would. The only distinguishing feature is that it sets the immutable bit afterwards, but that's not a sufficient way to express that the name servers are to be trusted.

Comment 1 Pavel Šimerda (pavlix) 2014-11-18 12:01:33 UTC
Created attachment 958529 [details]
patch to use a symbolic link

The least dnssec-trigger can do is to use a symlink pointing to its own directory instead an actual file. This has numerous advantages and has been also proposed by resolved developers who can make use of the symlinks to distinguish certain configurations. I've been happily using this patch for a while now.

Comment 2 Pavel Šimerda (pavlix) 2014-11-18 12:02:10 UTC
s/to its own directory/to a file in its own directory/

Comment 3 Tomáš Hozza 2014-11-18 12:35:53 UTC
(In reply to Pavel Šimerda (pavlix) from comment #0)
> Currently dnssec-trigger writes trusted validating nameservers to
> /etc/resolv.conf just as any other tool would. The only distinguishing
> feature is that it sets the immutable bit afterwards, but that's not a
> sufficient way to express that the name servers are to be trusted.

The purpose of the immutable bit is not to express that the name servers are to be trusted.

It is a mechanism to prevent other (potentially malicious) software from changing the content of resolv.conf!

Comment 4 Pavel Šimerda (pavlix) 2014-11-18 12:39:21 UTC
Created attachment 958547 [details]
updated patch

The new patch fixes issues with missing files and also creates an additional symlink /etc/resolv-secure.conf. The new symlink clearly expresses that the included name servers are to be trusted for dnssec validation. Any application or library can use it to confirm that the AD flag is to be trusted, while it would clear out the AD flag otherwise.

Comment 5 Pavel Šimerda (pavlix) 2014-11-18 15:59:33 UTC
(In reply to Tomas Hozza from comment #3)
> > that's not a
> > sufficient way to express that the name servers are to be trusted.
> 
> The purpose of the immutable bit is not to express that the name servers are
> to be trusted.

That's exactly why I wrote it that way.

Comment 6 Pavel Šimerda (pavlix) 2014-11-18 16:58:03 UTC
Additional security note. The way it works, i.e. that /etc/resolv.conf and /etc/resolv-secure.conf are just symlinks to the same data have one great advantage that the target file, as well as /etc/resolv-secure.conf symlink, could be covered by a selinux policy that would only allow dnssec-trigger (and the unconfined administrator of course) to change them.

The /etc/resolv.conf would still need somewhat more open policy so that for example NetworkManager can write it when dnssec-trigger is turned off or not installed. The good thing is, that even priviliged apps that look up the target of the /etc/resolv.conf symlink, wouldn't be able to write to the target. The bad thing is that those apps would have to be fixed so that they don't attempt to do that.

Comment 7 Pavel Šimerda (pavlix) 2014-11-18 16:59:44 UTC
(In reply to Pavel Šimerda (pavlix) from comment #6)
> apps would have to be fixed so that they don't attempt to do that.

Or at least to attempt to remove the symlink first.

Comment 8 Pavel Šimerda (pavlix) 2015-01-20 10:13:27 UTC
Fixed in rawhide, moving to F21.

Comment 9 Fedora Update System 2015-01-26 20:47:40 UTC
dnssec-trigger-0.12-18.fc21 has been submitted as an update for Fedora 21.
https://admin.fedoraproject.org/updates/dnssec-trigger-0.12-18.fc21

Comment 10 Fedora Update System 2015-01-28 19:56:12 UTC
Package dnssec-trigger-0.12-18.fc21:
* should fix your issue,
* was pushed to the Fedora 21 testing repository,
* should be available at your local mirror within two days.
Update it with:
# su -c 'yum update --enablerepo=updates-testing dnssec-trigger-0.12-18.fc21'
as soon as you are able to.
Please go to the following url:
https://admin.fedoraproject.org/updates/FEDORA-2015-1279/dnssec-trigger-0.12-18.fc21
then log in and leave karma (feedback).

Comment 11 Fedora Update System 2015-03-17 11:06:56 UTC
dnssec-trigger-0.12-19.fc22 has been submitted as an update for Fedora 22.
https://admin.fedoraproject.org/updates/FEDORA-2015-3864/dnssec-trigger-0.12-19.fc22

Comment 12 Fedora Update System 2015-03-17 11:07:15 UTC
dnssec-trigger-0.12-19.fc21 has been submitted as an update for Fedora 21.
https://admin.fedoraproject.org/updates/FEDORA-2015-3843/dnssec-trigger-0.12-19.fc21

Comment 13 Fedora Update System 2015-03-26 22:04:26 UTC
dnssec-trigger-0.12-19.fc21 has been pushed to the Fedora 21 stable repository.  If problems still persist, please make note of it in this bug report.

Comment 14 Fedora Update System 2015-04-21 18:49:00 UTC
dnssec-trigger-0.12-20.fc22 has been pushed to the Fedora 22 stable repository.  If problems still persist, please make note of it in this bug report.


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