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Bug 790105 - Filter out inappropriate IP addresses from IPA dynamic DNS update
Summary: Filter out inappropriate IP addresses from IPA dynamic DNS update
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 6
Classification: Red Hat
Component: sssd
Version: 6.3
Hardware: Unspecified
OS: Unspecified
medium
unspecified
Target Milestone: rc
: ---
Assignee: Jakub Hrozek
QA Contact: Kaushik Banerjee
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2012-02-13 16:48 UTC by Dmitri Pal
Modified: 2020-05-02 16:23 UTC (History)
5 users (show)

Fixed In Version: sssd-1.9.1-1.el6
Doc Type: Bug Fix
Doc Text:
Do not document.
Clone Of:
Environment:
Last Closed: 2013-02-21 09:35:24 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)
output of multicast-broadcast scenarios (4.81 KB, text/plain)
2013-02-06 09:56 UTC, Kaleem 		no flags Details
View All


Links
System ID Private Priority Status Summary Last Updated
Github SSSD sssd issues 1991 0 None None None 2020-05-02 16:23:21 UTC
Red Hat Product Errata RHSA-2013:0508 0 normal SHIPPED_LIVE Low: sssd security, bug fix and enhancement update 2013-02-20 21:30:10 UTC

Description Dmitri Pal 2012-02-13 16:48:18 UTC 
This bug is created as a clone of upstream ticket:
https://fedorahosted.org/sssd/ticket/949

This was started last month, but then got forgotten:

https://fedorahosted.org/pipermail/sssd-devel/2011-July/006493.html

When used with the `ipa_dyndns_iface option`, the dynamic DNS code would 
blindly put in any addresses the interface has. I think we should filter 
addresses such as multicast, loopback and IPv6 link-local -- they don't 
belong to DNS.
Comment 1 RHEL Program Management 2012-07-10 06:13:31 UTC 
This request was not resolved in time for the current release.
Red Hat invites you to ask your support representative to
propose this request, if still desired, for consideration in
the next release of Red Hat Enterprise Linux.
Comment 2 RHEL Program Management 2012-07-11 02:04:01 UTC 
This request was erroneously removed from consideration in Red Hat Enterprise Linux 6.4, which is currently under development.  This request will be evaluated for inclusion in Red Hat Enterprise Linux 6.4.
Comment 6 Kaleem 2013-02-06 09:56:32 UTC 
Created attachment 693835 [details]
output of multicast-broadcast scenarios

Jakub,

Multicast and Broadcast addresses are not being filtered out.

Multicast address:
=================
[root@rhel64master ~]# ipa dnsrecord-show testrelm.com rhel64client1
  Record name: rhel64client1
  A record: 224.0.0.1
  AAAA record: 2620:52:0:41c9:5054:ff:fe73:69b8
  SSHFP record: 1 1 57EA2E45D2179CA8CB657F87D193779CD748443E, 2 1 E63F99C498C201838B383EFD423D7A38B3370F04
[root@rhel64master ~]#

Broadcast address:
=================
[root@rhel64master ~]# ipa dnsrecord-show testrelm.com rhel64client1
  Record name: rhel64client1
  A record: 10.65.201.255
  AAAA record: 2620:52:0:41c9:5054:ff:fe73:69b8
  SSHFP record: 1 1 57EA2E45D2179CA8CB657F87D193779CD748443E, 2 1 E63F99C498C201838B383EFD423D7A38B3370F04
[root@rhel64master ~]#

Am i missing something here?

Please find the attachment for details.
Comment 7 Jakub Hrozek 2013-02-08 10:31:01 UTC 
The multicast check is wrong, please file a bug against the SSSD. I have a patch already.

I'm not sure about the broadcast check, I think the only permitted address for IPv4 broadcast is 255.255.255.255. When I set that one, SSSD correctly detected it as broadcast.
Comment 8 Kaleem 2013-02-08 17:21:31 UTC 
(In reply to comment #7)
> The multicast check is wrong, please file a bug against the SSSD. I have a
> patch already.
> 
> I'm not sure about the broadcast check, I think the only permitted address
> for IPv4 broadcast is 255.255.255.255. When I set that one, SSSD correctly
> detected it as broadcast.

255.255.255.255 is broadcast address for zero network 0.0.0.0 
Every subnet has a broadcast address. for example in above subnet 10.65.201.0/24 , the broadcast address is 10.65.201.255. 
So my understanding is that any address ending in 0.0.0.255 should be filtered out.
Correct me if i am wrong.
Comment 9 Jakub Hrozek 2013-02-08 17:25:57 UTC 
(In reply to comment #8)
> (In reply to comment #7)
> > The multicast check is wrong, please file a bug against the SSSD. I have a
> > patch already.
> > 
> > I'm not sure about the broadcast check, I think the only permitted address
> > for IPv4 broadcast is 255.255.255.255. When I set that one, SSSD correctly
> > detected it as broadcast.
> 
> 255.255.255.255 is broadcast address for zero network 0.0.0.0 
> Every subnet has a broadcast address. for example in above subnet
> 10.65.201.0/24 , the broadcast address is 10.65.201.255. 
> So my understanding is that any address ending in 0.0.0.255 should be
> filtered out.
> Correct me if i am wrong.

Yes, but these subnet addresses are not returned by getifaddrs(). The only broadcast address that you can reasonably configure is 255.255.255.255.
Comment 10 Kaleem 2013-02-08 18:10:16 UTC 
Verified for loopback and link-local addresses.

Multicast and subnet broadcast address are not being filtered out. so will file another bugzilla for these addresses.

sssd version:
=============
[root@rhel64client1 ~]# rpm -q sssd
sssd-1.9.2-82.el6.x86_64
[root@rhel64client1 ~]#

Steps used to verify:
====================
(1)Loopback address:
=================
On Client:
==========
(a)sssd.conf has lo interface for ipa_dyndns_iface parameter

[root@rhel64client1 ~]# cat /etc/sssd/sssd.conf|grep ipa_dyn
ipa_dyndns_update = True
ipa_dyndns_iface = lo 
[root@rhel64client1 ~]#

(b)sssd debug log shows that Loopback address are filtered.
(Tue Feb  5 20:09:17 2013) [sssd[be[testrelm.com]]] [ok_for_dns] (0x0200): Loopback IPv4 address 127.0.0.1
(Tue Feb  5 20:09:17 2013) [sssd[be[testrelm.com]]] [ok_for_dns] (0x0200): Loopback IPv6 address ::1
(Tue Feb  5 20:09:18 2013) [sssd[be[testrelm.com]]] [resolv_gethostbyname_next] (0x0200): No more address families to retry

On Server:
==========
(a)No A record exist for rhel64client1
[root@rhel64master ~]# ipa dnsrecord-show testrelm.com rhel64client1
  Record name: rhel64client1
  SSHFP record: 1 1 57EA2E45D2179CA8CB657F87D193779CD748443E, 2 1 E63F99C498C201838B383EFD423D7A38B3370F04
[root@rhel64master ~]#

(2)Link local IPv6 address:
========================
(a)Interface having global and link local ip addresses

   eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 52:54:00:73:69:b8 brd ff:ff:ff:ff:ff:ff
    inet 224.0.0.1/0 brd 255.255.255.255 scope global eth2:1
    inet6 2620:52:0:41c9:5054:ff:fe73:69b8/64 scope global dynamic 
       valid_lft 2591865sec preferred_lft 604665sec
    inet6 fe80::5054:ff:fe73:69b8/64 scope link 
       valid_lft forever preferred_lft forever
[root@rhel64client1 ~]#

global ipv6 address : 2620:52:0:41c9:5054:ff:fe73:69b8/64
link local ipv6 address : fe80::5054:ff:fe73:69b8/64

(b)link local ipv6 address is filtered out for dynamic dns update

(Wed Feb  6 13:10:00 2013) [sssd[be[testrelm.com]]] [delayed_online_authentication_callback] (0x0200): Backend is online, starting delayed online authentication.
(Wed Feb  6 13:10:00 2013) [sssd[be[testrelm.com]]] [ok_for_dns] (0x0200): Link local IPv6 address fe80::5054:ff:fe73:69b8
(Wed Feb  6 13:10:01 2013) [sssd[be[testrelm.com]]] [resolv_gethostbyname_next] (0x0200): No more address families to retry
(Wed Feb  6 13:10:01 2013) [sssd[be[testrelm.com]]] [resolv_gethostbyname_next] (0x0200): No more address families to retry
(Wed Feb  6 13:10:01 2013) [sssd[be[testrelm.com]]] [create_nsupdate_message] (0x0200): Creating update message for realm [TESTRELM.COM] and zone [testrelm.com].

(c)Global ipv6 adddress added on ipa-server as AAAA record and not the Link local IPv6 address fe80::5054:ff:fe73:69b8
[root@rhel64master ~]# ipa dnsrecord-show testrelm.com rhel64client1
  Record name: rhel64client1
  A record: 10.65.201.102
  AAAA record: 2620:52:0:41c9:5054:ff:fe73:69b8
  SSHFP record: 1 1 57EA2E45D2179CA8CB657F87D193779CD748443E, 2 1 E63F99C498C201838B383EFD423D7A38B3370F04
[root@rhel64master ~]#
Comment 11 errata-xmlrpc 2013-02-21 09:35:24 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.

http://rhn.redhat.com/errata/RHSA-2013-0508.html
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