GNU bug report logs - #56327
Regression: openssh service fails to start if system has no IPv6

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: André Batista <nandre <at> riseup.net>
To: bug-guix <at> gnu.org
Subject: Regression: openssh service fails to start if system has no IPv6
Date: Thu, 30 Jun 2022 16:20:18 -0300

Hi Guix!

Since commit d2b3400f79ffaed3357650307376ab69a7ec3b1b, ssh-daemon
fails to start when the system is using shepherd 0.9.1, but has no
support to IPv6. This is a result of shepherd trying to listen on a
IPv6 address without prior checking.

See https://issues.guix.gnu.org/55335.

PS: Yeah, I know, it's 2022 and in a few months it will be 2023 and
everyone's toilet should have its own IPv6 address by now and report
its users health conditions to a plethora of pharmaceutical
advertisers. Nonetheless, in this backward corner of the Earth there
is still one guix machine without IPv6, believe it or not! :D

Message #8 received at 56327 <at> debbugs.gnu.org (full text, mbox):

From: André Batista <nandre <at> riseup.net>
To: 56327 <at> debbugs.gnu.org
Subject: Re: bug#56327: Regression: openssh service fails to start if system
 has no IPv6
Date: Thu, 30 Jun 2022 16:31:41 -0300

[Message part 1 (text/plain, inline)]

I've tested the following patch, which tests for IPv6 support, on
both a system without IPv6 and another with it, but I have not tested
on a system with shepherd < 0.9.1. Hopefuly it works as expected.

Cheers!

[ssh-service.patch (text/plain, attachment)]

Message #13 received at 56327-done <at> debbugs.gnu.org (full text, mbox):

From: Ludovic Courtès <ludo <at> gnu.org>
To: André Batista <nandre <at> riseup.net>
Cc: 56327-done <at> debbugs.gnu.org
Subject: Re: bug#56327: Regression: openssh service fails to start if system
 has no IPv6
Date: Fri, 01 Jul 2022 23:56:17 +0200

Hi!

André Batista <nandre <at> riseup.net> skribis:

> I've tested the following patch, which tests for IPv6 support, on
> both a system without IPv6 and another with it, but I have not tested
> on a system with shepherd < 0.9.1. Hopefuly it works as expected.

Older versions of shepherd are not relevant in this case.

I’ve fixed it slightly differently in commit
bf7e07d299b197891110fbd8c717badbab06a472, to avoid a file descriptor
leak.  Thanks!

Out of curiosity: I suppose you’re explicitly disabling IPv6 by using a
custom kernel or with an activation snippet that fiddles with /proc or
/sys, right?

Ludo’.

Message #16 received at 56327-done <at> debbugs.gnu.org (full text, mbox):

From: André Batista <nandre <at> riseup.net>
To: Ludovic Courtès <ludo <at> gnu.org>
Cc: 56327-done <at> debbugs.gnu.org
Subject: Re: bug#56327: Regression: openssh service fails to start if system
 has no IPv6
Date: Fri, 1 Jul 2022 21:27:32 -0300

sex 01 jul 2022 às 23:56:17 (1656730577), ludo <at> gnu.org enviou:
> I’ve fixed it slightly differently in commit
> bf7e07d299b197891110fbd8c717badbab06a472, to avoid a file descriptor
> leak.  Thanks!

Tremendous difference, I'd say, both for closing the socket and for
'consing' the single test condition instead of the cumbersome
repeated testing I had written. Thanks for lessoning me and for the
quick fix!

> Out of curiosity: I suppose you’re explicitly disabling IPv6 by using a
> custom kernel or with an activation snippet that fiddles with /proc or
> /sys, right?

I am building a custom minimal kernel with 'CONFIG_IPV6=n'.

Toutes mes amitiés!

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