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[[!meta copyright="Copyright © 2011, 2012, 2013, 2014, 2015 Free Software
Foundation, Inc."]]
[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
id="license" text="Permission is granted to copy, distribute and/or modify this
document under the terms of the GNU Free Documentation License, Version 1.2 or
any later version published by the Free Software Foundation; with no Invariant
Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license
is included in the section entitled [[GNU Free Documentation
License|/fdl]]."]]"""]]
[[!tag open_issue_porting]]
# Open Issues
* [[!debbug 616290]]
* [[Proper Hurdy DHCP support|hurd/translator/pfinet/dhcp]]
* [[!message-id desc="dhclient aborting with a stack smashing error"
"874ngfvwn4.fsf@kepler.schwinge.homeip.net"]]
IRC, freenode, #hurd, 2013-08-21:
<teythoon> yay, I fixed the path of the dhcp leases file...
<teythoon> ... and now dhclient dies of a buffer overflow
<teythoon> fortunately the fix is rather simple, anyone who cares about
the security of his box just has to stop using isc software
<teythoon> the code is full of stuff like char foo[100]; /* surely
that's enough */
<pinotree> note that our version of isc-dchp (the one in ports) is
older than the latest one available in unstable (which is still older
than the latest upstream releases)
<teythoon> so?
<pinotree> dunno, might have been fixed or not
<teythoon> ^^ yeah sure
<gnu_srs> A lot of software has these limitations and PATH_MAX,
MAXPATHLEN issues :(
<pinotree> having a limitation is not a problem per-se
<teythoon> no, only software written in c has these kind of problems
<pinotree> the problem is not checking whether the limits are hit
<teythoon> well, looking at the source of isc-dhcp my time is better
spent making another dhcp client work on hurd
<teythoon> also reading up on bug #616290 does make me want to avoid
touching it ever
<braunr> hehe
<gnu_srs> teythoon: somebody was offering an alternative to the isc
dhcpclient, but I think it was rejected by Samuel?
<teythoon> why would he do that?
<braunr> probably for compliance
<gnu_srs> He probably thought they would release a new version soon, is
4.3.0 out yet?
<teythoon> well, as soon as my fixes for ifupdown go in, dhclient will
start crashing
<teythoon> no, there is no new version released
<teythoon> no major one that is
<teythoon> 4.2.5 is out
<gnu_srs> can't you just increase the buffer size, where is the problem
exactly?
<teythoon> I have no idea
<gnu_srs> The Hurd patches are not in 4.2.5, they were promised for
4.3.0a1.
<gnu_srs> Still the buffer overflow problem might be present in 4.2.5
if patched to build on Hurd.
<braunr> there, darnassus now has a fully featured git/gitweb service
<teythoon> :)
<teythoon> btw, I managed to reproduce the crash reliably
<teythoon> rm /var/lib/dhcp/*; dhclient -v /dev/eth0 ... *boom*
<teythoon> ditch the -v, everything works, and now that there is a
lease file, you can add the -v again and it works
<braunr> ew :)
<teythoon> and what has dhclient.c to say for its defense?
<teythoon> log_info("%s", "");
<teythoon> hm, not much :/
IRC, freenode, #hurd, 2013-08-22:
<teythoon> uh, the isc-dhcp situation is a huge pita, the source on
-ports does not compile anymore :/
IRC, freenode, #hurd, 2013-08-23:
<gnu_srs> teythoon: Was it the slash in the network interface names
that caused the buffer overflow in dhclient?
<teythoon> gnu_srs: no, previously no dhcp leases file was written and
everything was fine
<pinotree> teythoon: did you really develop your patch against that old
version of ifupdown?
<teythoon> gnu_srs: now it is written, and for some reason dhclient
crashes *iff* -v is given *and* there is no previous lease file
<teythoon> pinotree: no, I did not. that was only reportbug including
information from my desktop machine without asking me
<teythoon> but when I first looked at ifupdown it was still a 6000
lines noweb file >,<
<teythoon> that was fun
<pinotree> which version is it against?
<teythoon> hg tip
IRC, freenode, #hurd, 2013-08-30:
<tschwinge> teythoon: I understand correctly that you found that
id:"874ngfvwn4.fsf@kepler.schwinge.homeip.net" in fact was really
"just" a buffer overflow in the dhclient code?
<teythoon> tschwinge: ah, most interesting, I didn't realize that you
stumbled across this as well
<teythoon> to be honest I don't know what's going on there, I only
observed what I wrote in my report
<teythoon> for me it started crashing once the lease file was actually
a valid path (i.e. not to a non-existing directory b/c of the slashes
in /dev/eth0)
<teythoon> I tried to rebuild the package served on debian-ports, but
that failed
IRC, freenode, #hurd, 2014-01-03:
<congzhang> dhcp 4.3 alpha released
<congzhang> and PATH_MAX issue was fixed
IRC, freenode, #hurd, 2014-01-21:
<gnu_srs> teythoon: what about this? *** stack smashing detected ***:
dhclient terminated
<teythoon> gnu_srs: well, dhclient dies
<teythoon> i've seen this, it comes and goes
<teythoon> not sure what happens, but i tend to blame it on our
custom-built dhcp package
<teythoon> from debian-ports, and it's outdated
<teythoon> it's most likely not your fault
<gnu_srs> i thought there was a new upstream by now
<teythoon> and the network configuration can be done with passive
translators as it was always done
<teythoon> there was ?
<gnu_srs> there is one recently released, haven't checked yet
<gnu_srs> in experimental: 4.3.0a1-2, does still not build out of the
box
<teythoon> there was, but it does not seem to build on the hurd
<teythoon>
https://buildd.debian.org/status/logs.php?pkg=isc-dhcp&arch=hurd-i386
<teythoon> the most recent version is from debian-ports
IRC, freenode, #hurd, 2014-01-24:
<braunr> stack smashing detected ***: dhclient terminated
<braunr> how nice
<tschwinge> braunr: dhclient:
http://news.gmane.org/find-root.php?message_id=%3C874ngfvwn4.fsf%40kepler.schwinge.homeip.net%3E
<tschwinge> braunr: And I thought, teythoon had found this to be a
buffer overflow; something like char dev[10], and for us the path to
the dev (/dev/eth0) was longer (but I may be misremebering).
<braunr> tschwinge: sounds reasonable
<tschwinge> braunr: By the way: I'm seeing this segfault all the time
during boot, but when I again run it manually (root login), it works
fine.
<braunr> tschwinge: you mean the dhclient one µ?
<tschwinge> Yes.
<braunr> mhm
<teythoon> braunr, tschwinge: i never found the cause of the dhclient
issue
<teythoon> i blame the (outdated) build on debian-ports
IRC, freenode, #hurd, 2014-01-30:
<youpi> err, still nobody found the dhclient bug?
<gnu_srs> youpi: You found the dh-client bug, right?
<youpi> gnu_srs: yes, the dhclient bug was in libc, as tschwinge
guessed
<youpi> I'll probably upload a fixed glibc on debian-ports
<gnu_srs> youpi: dhclient starts OK with libc 2.17-98~0
<youpi> btw, the experimental version of isc-dhcp has a newer
occurrence of PATH_MAX
<gnu_srs> :-(
<youpi> (aside from not including the needed debian files for
hurd-i386)
* IPv6
IRC, freenode, #hurd, 2014-02-23:
<gg0> seems dhclient can't also set ipv6 translator
<gg0> cheated by setting it manually, i had probably screwed it up
somehow
<gg0> exim was complaining 2014-02-23 22:26:41 IPv6 socket creation
failed: Address family not supported by protocol
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