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Bug 1550637 - Server time not being synchronised with NTP after upgrading ntp packages
Summary: Server time not being synchronised with NTP after upgrading ntp packages
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: ntp
Version: 7.4
Hardware: All
OS: Linux
unspecified
medium
Target Milestone: rc
: ---
Assignee: Miroslav Lichvar
QA Contact: Ondrej Mejzlik
URL:
Whiteboard:
Depends On:
Blocks: 1630913 1663257
TreeView+ depends on / blocked
 
Reported: 2018-03-01 16:43 UTC by Miroslav Lichvar
Modified: 2019-09-24 08:50 UTC (History)
6 users (show)

Fixed In Version: ntp-4.2.6p5-29.el7
Doc Type: No Doc Update
Doc Text:
Clone Of: 1548416
Environment:
Last Closed: 2019-08-06 12:41:44 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Network Time Protocol 3465 0 None None None 2019-08-08 13:05:25 UTC
Red Hat Product Errata RHSA-2019:2077 0 None None None 2019-08-06 12:41:50 UTC

Description Miroslav Lichvar 2018-03-01 16:43:31 UTC 
+++ This bug was initially created as a clone of Bug #1548416 +++

As can be seen below: 10.4.210.2 can be seen by 10.4.2.2 but not the other way.
Can revert 10.4.2.2 to previous ntp rpms and it does work.

This system is 10.4.210.2

[root@medium-210-sib]# ntpdc -nc dmpeers
     remote           local      st poll reach  delay   offset    disp
=======================================================================
.127.127.28.0    127.0.0.1        0   16  377 0.00000  0.000131 0.01555
 10.1.210.2      10.4.210.2       2   64    0 0.00064 -0.000009 3.99217
*127.127.28.1    127.0.0.1        0   16  377 0.00000  0.000102 0.01553
 10.5.35.2       10.4.210.2       1   64    0 0.00279 -0.000043 3.99217
.10.4.3.2        10.4.210.2       1   64  100 0.00179 -0.000115 0.97110
 239.0.1.1       10.4.210.2      16   64    0 0.00000  0.000000 4.00000
 10.2.1.2        10.4.210.2       2   64  100 0.00296 -0.000788 0.66574
 10.3.210.2      10.4.210.2       2   64    0 0.00240 -0.000272 3.99217
 10.4.7.2        10.4.210.2       2   64  200 0.00220 -0.000374 0.97160
 10.0.0.125      10.4.210.2       2   64    0 0.00177 -0.000760 3.99217
 10.0.0.126      10.4.210.2       2   64  200 0.00166 -0.000461 0.97157
 10.0.7.2        10.4.210.2       4   64    0 0.00185 -0.000116 3.99217
 10.2.210.2      10.4.210.2       2   64  100 0.00290 -0.000275 0.66579
 10.5.210.2      10.4.210.2       1   64    0 0.00189 -0.000118 3.99217
 10.3.35.2       10.4.210.2       2   64    0 0.00310  0.000027 3.99217
 10.1.2.2        10.4.210.2       2   64   20 0.00211 -0.000426 0.66432
[root@medium-210-sib]# rpm -qa | grep ntp
fontpackages-filesystem-1.41-1.1.el6.noarch
ntp-4.2.6p5-10.el6_8.2.x86_64
ntpdate-4.2.6p5-10.el6_8.2.x86_64

Linux medium-210-sib 2.6.32-696.16.1.el6.x86_64 #1 SMP Sun Oct 8 09:45:56 EDT 2017 x86_64 x86_64 x86_64 GNU/Linux
-------------------------------------------------------------------------------------------------------------------
This system is 10.4.2.2

[fsr@medium-2-sib]$ ntpdc -nc dmpeers
     remote           local      st poll reach  delay   offset    disp
=======================================================================
.127.127.28.0    127.0.0.1        0   16  377 0.00000 -0.000131 0.01753
 10.1.210.2      10.4.2.2         2   64  376 0.00226 -0.000575 0.03073
*127.127.28.1    127.0.0.1        0   16  377 0.00000 -0.000112 0.01566
 10.4.210.2      10.4.2.2         1   64  376 0.00340  0.000487 0.03096
 10.5.35.2       10.4.2.2         1   64  376 0.00000 -0.001461 0.03085
.10.4.3.2        10.4.2.2         1   64  376 0.00195  0.000049 0.03062
 239.0.1.1       10.4.2.2        16   64    0 0.00000  0.000000 4.00000
 10.2.1.2        10.4.2.2         2   64  367 0.00000 -0.001807 0.03094
 10.3.210.2      10.4.2.2         2   64  376 0.00087 -0.000004 0.03056
 10.4.7.2        10.4.2.2         4   64  377 0.00000 -0.000760 0.03084
 10.0.0.125      10.4.2.2         2   64  376 0.00233  0.000076 0.03104
 10.0.0.126      10.4.2.2         2   64  376 0.00000 -0.000634 0.03061
 10.0.7.2        10.4.2.2         4   64  376 0.00000 -0.001087 0.03087
 10.2.210.2      10.4.2.2         3   64  377 0.00418  0.000464 0.03105
 10.5.210.2      10.4.2.2         1   64  376 0.00325  0.000807 0.03072
 10.3.35.2       10.4.2.2         2   64  377 0.00000 -0.000824 0.03104
 10.1.2.2        10.4.2.2         2   64  377 0.00000 -0.000489 0.03055
[fsr@medium-2-sib]$ rpm -qa | grep ntp
ntpdate-4.2.6p5-12.el6_9.2.x86_64
ntp-4.2.6p5-12.el6_9.2.x86_64

...

--- Additional comment from Carl Baker on 2018-03-01 10:03:55 EST ---

Will do. We have somebody looking at ntp source code changes and the last that I heard there suspicion about a ttl check with some kind of a system max ttl time variable and the thought was maybe the system max ttl time wasn't being set so it was blowing by the check. Just a thought.

--- Additional comment from Carl Baker on 2018-03-01 10:12:17 EST ---

Question - Since both 10.4.6.2 and 10.4.2.2 both have ntp 9.2 and they can't see each other but they can see systems that contain the old ntp 8.2 that works(ie, 10.5.35.2) doesn't it make sense that it is the sending as opposed to the receiving that is not working.

--- Additional comment from Miroslav Lichvar on 2018-03-01 10:59:59 EST ---

That's a very good point and I think you are right that it's related to the sys_maxttl variable.

The fix for CVE-2017-6464 made a change to prevent reading past the sys_ttl array. However, the sys_ttlmax variable is not set correctly when parsing a config file which does not have a ttl directive. In such case it is set to -1, so the default value of 32 (which should be selected by ttl 1 on the broadcast line) from sys_ttl is ignored and some bogus value is used instead.

Can you please try adding the following line to ntp.conf?

ttl 0 32 64 96 128 160 192 224
Comment 8 errata-xmlrpc 2019-08-06 12:41:44 UTC 
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://access.redhat.com/errata/RHSA-2019:2077
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