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[[!tag open_issue_porting]]

In order to use DHCP, you need to install the `ifupdown` and `isc-dhcp-client`
packages, and manually create the following symbolic link:

    # ln -s ../rcS.d/S10networking /etc/rc.boot/

During execution at boot time, the `S10networking` script will emit some error
messages while trying to configure the loopback interface.  These are not
fatal.

Debian GNU/Hurd doesn't currently execute Debian standard `/etc/rcS.d/*` boot
scripts, but has its own `/libexec/rc` script -- which integrates scripts from
`/etc/rc.boot/` instead.


# 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