[Buildroot] [PATCH 1/1] package/{chrony, ntp, openntpd}: turn off DNSSEC validation

[Buildroot] [PATCH 1/1] package/{chrony, ntp, openntpd}: turn off DNSSEC validation

[James Hilliard]

We have a chicken and egg problem: validation of DNSSEC signatures
doesn't work without a correct clock, but to set the correct clock we
need to contact NTP servers which requires resolving a hostname, which
would normally require DNSSEC validation.

Let's break the cycle by excluding NTP hostname resolution from
validation for now.

Details:
https://github.com/systemd/systemd/commit/abf4e5c1d3ad767bc0ed67883e8e4d916af095ec

Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
---
 package/chrony/chrony.service | 4 ++++
 package/ntp/ntpd.service      | 4 ++++
 package/openntpd/ntpd.service | 4 ++++
 3 files changed, 12 insertions(+)

diff --git a/package/chrony/chrony.service b/package/chrony/chrony.service
index 325b63c492..210122cf5d 100644
--- a/package/chrony/chrony.service
+++ b/package/chrony/chrony.service
@@ -4,6 +4,10 @@ After=syslog.target network.target
 Conflicts=systemd-timesyncd.service
 
 [Service]
+# Turn off DNSSEC validation for hostname look-ups, since those need the
+# correct time to work, but we likely won't acquire that without NTP. Let's
+# break this chicken-and-egg cycle here.
+Environment=SYSTEMD_NSS_RESOLVE_VALIDATE=0
 ExecStart=/usr/sbin/chronyd -n
 Restart=always
 
diff --git a/package/ntp/ntpd.service b/package/ntp/ntpd.service
index 7964c5389b..9a0f4c6dbf 100644
--- a/package/ntp/ntpd.service
+++ b/package/ntp/ntpd.service
@@ -5,6 +5,10 @@ After=network.target
 [Service]
 Type=forking
 PIDFile=/run/ntpd.pid
+# Turn off DNSSEC validation for hostname look-ups, since those need the
+# correct time to work, but we likely won't acquire that without NTP. Let's
+# break this chicken-and-egg cycle here.
+Environment=SYSTEMD_NSS_RESOLVE_VALIDATE=0
 ExecStart=/usr/sbin/ntpd -g -p /run/ntpd.pid
 
 [Install]
diff --git a/package/openntpd/ntpd.service b/package/openntpd/ntpd.service
index a4ffa7318c..c2924b0c5c 100644
--- a/package/openntpd/ntpd.service
+++ b/package/openntpd/ntpd.service
@@ -5,6 +5,10 @@ Conflicts=systemd-timesyncd.service
 
 [Service]
 Type=simple
+# Turn off DNSSEC validation for hostname look-ups, since those need the
+# correct time to work, but we likely won't acquire that without NTP. Let's
+# break this chicken-and-egg cycle here.
+Environment=SYSTEMD_NSS_RESOLVE_VALIDATE=0
 ExecStart=/usr/sbin/ntpd -s -d
 
 [Install]
-- 
2.25.1

[Buildroot] [PATCH 1/1] package/{chrony, ntp, openntpd}: turn off DNSSEC validation

[Thomas Petazzoni]

On Thu,  8 Jul 2021 05:16:27 -0600
James Hilliard <james.hilliard1@gmail.com> wrote:

> We have a chicken and egg problem: validation of DNSSEC signatures
> doesn't work without a correct clock, but to set the correct clock we
> need to contact NTP servers which requires resolving a hostname, which
> would normally require DNSSEC validation.
> 
> Let's break the cycle by excluding NTP hostname resolution from
> validation for now.
> 
> Details:
> https://github.com/systemd/systemd/commit/abf4e5c1d3ad767bc0ed67883e8e4d916af095ec
> 
> Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
> ---
>  package/chrony/chrony.service | 4 ++++
>  package/ntp/ntpd.service      | 4 ++++
>  package/openntpd/ntpd.service | 4 ++++
>  3 files changed, 12 insertions(+)

I'm not an expert in this area, but the explanation seems sensible, and
nobody complained so far, so I've applied to master. Thanks!

Thomas
-- 
Thomas Petazzoni, CTO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

Re: [Buildroot] [PATCH 1/1] package/{chrony, ntp, openntpd}: turn off DNSSEC validation

[Peter Korsgaard]

>>>>> "James" == James Hilliard <james.hilliard1@gmail.com> writes:

 > We have a chicken and egg problem: validation of DNSSEC signatures
 > doesn't work without a correct clock, but to set the correct clock we
 > need to contact NTP servers which requires resolving a hostname, which
 > would normally require DNSSEC validation.

 > Let's break the cycle by excluding NTP hostname resolution from
 > validation for now.

 > Details:
 > https://github.com/systemd/systemd/commit/abf4e5c1d3ad767bc0ed67883e8e4d916af095ec

 > Signed-off-by: James Hilliard <james.hilliard1@gmail.com>

Committed to 2021.02.x and 2021.05.x, thanks.

-- 
Bye, Peter Korsgaard
_______________________________________________
buildroot mailing list
buildroot@busybox.net
http://lists.busybox.net/mailman/listinfo/buildroot