'Re: dhcpd -6: buffer overflow detected'

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List: dhcp-users
Subject: Re: dhcpd -6: buffer overflow detected
From: perl-list <perl-list () network1 ! net>
Date: 2012-03-30 12:51:26
Message-ID: 7cd1c0f3-bf8b-40e4-8945-df4ebbe456ea () zimbra ! network1 ! net
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We use 4.2.3-p1 built from source on generic (bootstrapped) linux. We notice that it \
crashes more often than not when working with a renewal packet (I think only \
renewals) in DHCPv6. I believe that I saw somewhere that ISC is aware of the problem \
and is working on a solution. To be clear, we do not get any buffer overflow messages \
in the syslog. 

----- Original Message -----

> From: "Fred Zwarts (KVI)" <F.Zwarts@KVI.nl>
> To: dhcp-users@lists.isc.org
> Sent: Friday, March 30, 2012 6:21:06 AM
> Subject: dhcpd -6: buffer overflow detected

> We are using the ISC dhcpd server for both IPv4 and IPv6 for more
> than a
> year now. Up to recently, the Suse distribution included only version
> 3 of
> isc dhcp, so, in order to run in IPv6 mode, we downloaded the isc
> dhcp
> source code and built the server ourselves.
> We worked around a few problems for IPv6 and finally the
> dhcpd-4.2.1-P1
> version was running in a stable mode for many months now on a Suse
> Linux
> Enterprise System 11 SP1 x86_64 system, both for IPv4 and IPv6.
> Yesterday, we installed Service Pack 2 for SLES11, which now contains
> isc
> dhcpd 4.2.3-P2.
> In IPv4 mode, it was no problem to run the new dhcpd server with
> exactly the
> same configuration as before.
> However, in IPv6 mode the dhcpd server runs for something like one
> minute
> and then stops. In the syslog we find the message:

> Mar 29 13:30:10 SRV014 dhcpd: *** buffer overflow detected ***:
> /usr/sbin/dhcpd6 terminated

> We have tried several time to run the dhcpd server, but each time it
> crashes
> in the same way after about one minute. This happens also when the
> server
> runs in foreground mode.

> Fortunately, we still have the executable of the 4.2.1-P1, so we
> changed
> the soft link /usr/sbin/dhcpd6 to point to this old image. Now the
> server
> does not crash anymore.

> We don't know how exactly the 4.2.3-P2 version was built by Suse. So
> we are
> not sure whether this problem is caused by the way the source code
> was
> compiled, or by a change introduce between the releases of these two
> versions.
> Also we don't know whether there is a specific part in our
> configuration, or
> a specific packet sent by a client that triggers the crash.
> So, my question is whether someone else uses 4.2.3-P2 in IPv6 mode
> without
> problems.
> Also suggestions for diagnosing the problem further are welcome.

> Fred.Zwarts.

> _______________________________________________
> dhcp-users mailing list
> dhcp-users@lists.isc.org
> https://lists.isc.org/mailman/listinfo/dhcp-users

[Attachment #5 (text/html)]

<html><head><style type='text/css'>p { margin: 0; }</style></head><body><div \
style='font-family: Andale Mono; font-size: 10pt; color: #000000'>We use 4.2.3-p1 \
built from source on generic (bootstrapped) linux. &nbsp;We notice that it crashes \
more often than not when working with a renewal packet (I think only renewals) in \
DHCPv6. &nbsp;I believe that I saw somewhere that ISC is aware of the problem and is \
working on a solution. &nbsp;To be clear, we do not get any buffer overflow messages \
in the syslog. <div> </div><hr id="zwchr"><blockquote \
style="border-left:2px solid rgb(16, 16, \
255);margin-left:5px;padding-left:5px;color:#000;font-weight:normal;font-style:normal; \
text-decoration:none;font-family:Helvetica,Arial,sans-serif;font-size:12pt;">From: \
"Fred Zwarts (KVI)" &lt;F.Zwarts@KVI.nl&gt; To: \
dhcp-users@lists.isc.org Sent: Friday, March 30, 2012 6:21:06 \
AM Subject: dhcpd -6: buffer overflow detected We are using the ISC \
dhcpd server for both IPv4 and IPv6 for more than a year now. Up to recently, the \
Suse distribution included only version 3 of isc dhcp, so, in order to run in \
IPv6 mode, we downloaded the isc dhcp source code and built the server \
ourselves. We worked around a few problems for IPv6 and finally the dhcpd-4.2.1-P1 \
 version was running in a stable mode for many months now on a Suse Linux \
 Enterprise System 11 SP1 x86_64 system, both for IPv4 and IPv6. Yesterday, we \
installed Service Pack 2 for SLES11, which now contains isc dhcpd 4.2.3-P2. In \
IPv4 mode, it was no problem to run the new dhcpd server with exactly the same \
configuration as before. However, in IPv6 mode the dhcpd server runs for something \
like one minute and then stops. In the syslog we find the message: Mar 29 \
13:30:10 SRV014 dhcpd: *** buffer overflow detected ***: /usr/sbin/dhcpd6 \
terminated We have tried several time to run the dhcpd server, but each time \
it crashes in the same way after about one minute. This happens also when the \
server runs in foreground mode. Fortunately, we still &nbsp;have the \
executable of the 4.2.1-P1, so we changed the soft link /usr/sbin/dhcpd6 to point \
to this old image. Now the server does not crash anymore. We don't know \
how exactly the 4.2.3-P2 version was built by Suse. So we are not sure whether \
this problem is caused by the way the source code was compiled, or by a change \
introduce between the releases of these two versions. Also we don't know \
whether there is a specific part in our configuration, or a specific packet sent \
by a client that triggers the crash. So, my question is whether someone else uses \
4.2.3-P2 in IPv6 mode without problems. Also suggestions for diagnosing the \
problem further are welcome. Fred.Zwarts. \
 _______________________________________________ dhcp-users mailing \
list dhcp-users@lists.isc.org https://lists.isc.org/mailman/listinfo/dhcp-users </blockquote> </div></body></html>

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