Bug#1034465: reportbug: dhcpcd -U results in "Bad system call"

[Jeff Kletsky]

Package: dhcpcd
Version: 9.4.1-21
Severity: important
Tags: newcomer upstream
X-Debbugs-Cc: debia...@allycomm.com

Dear Maintainer,

TL;DR -- Apparently fixed upstream in dhcpcd-9.5.0 or later (-10.0.0 available)

* What led up to the situation?

Installed later version of nftables from "testing" which brought in a newer version of libc

While dhcpcd5/dhcpcd runs and obtains leases, the -U / --dumplease function fails with either
"Bad system call" or, if running under sudo, with "dhcpcd_readdumptimeout"

* What exactly did you do (or not do) that was effective (or
ineffective)?

Trying the versions of dhcpcd from testing and unstable did not resolve the issue.

Building locally from deb source (either stable or testing/unstable)
against the newer version of libc did not resolve the issue.

The issue appears to be impacting other systems that have later versions of libc
than does Debian Bullseye. Searching the upstream dhcpcd archive revealed

<https://github.com/NetworkConfiguration/dhcpcd/issues/159>

was reported by a user on Arch Linux, dhcpcd version 9.4.1 and glibc version 2.36

rsmarples indicates "Fixed in dhcpcd-9.5.0"

His comment appears to be roughly coincident with the release of dhcpcd-10.0.0

* What was the outcome of this action?
* What outcome did you expect instead?

At the present time, there is not a straightforward way for me to dump the DHCPv6
lease information. The dhcpcd -U command's output is used for scripts to adjust
firewall settings on an as-needed basis. Regrettably, Comcast's reliability
is not very good and IPv6 allocations change with every outage during the winter
storms and occasionally for no apparent reason. I can work around this locally.

I did try to rebase https://salsa.debian.org/debian/dhcpcd5 onto the upstream
dhcpcd-10.0.0 tag but found that I did not have enough knowldge of the code
to resolve the merge conflicts.

Building form upstream source at dhcpcd-10.0.0, without the Debian patches

./configure --prefix=/opt
make
sudo make install

and replacing the running version with the local build restores the -U functionality.

Just using the 10.0.0 build with the running 9.4.1 version was not sucessful, returning
"dhcpcd is not running" (though it was). This was not further pursued.

I have not tried building 9.5


-- System Information:
Debian Release: 11.6
APT prefers stable-updates
APT policy: (500, 'stable-updates'), (500, 'stable-security'), (500, 'proposed-updates'), (500, 'stable'), (90, 'testing'), (80, 'unstable')
Architecture: amd64 (x86_64)

Kernel: Linux 5.10.0-21-amd64 (SMP w/4 CPU threads)
Kernel taint flags: TAINT_PROPRIETARY_MODULE, TAINT_OOT_MODULE, TAINT_UNSIGNED_MODULE
Locale: LANG=C, LC_CTYPE=C.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages dhcpcd depends on:
ii dhcpcd-base 9.4.1-21
ii lsb-base 11.1.0
ii sysvinit-utils 2.96-7+deb11u1

dhcpcd recommends no packages.

Versions of packages dhcpcd suggests:
pn dhcpcd-gtk <none>

-- no debconf information

[Martin-Éric Racine]

On Sat, 15 Apr 2023 20:14:07 -0700 Jeff Kletsky
<debia...@allycomm.com> wrote:
> Package: dhcpcd
> Version: 9.4.1-21
> Severity: important
> Tags: newcomer upstream
> X-Debbugs-Cc: debia...@allycomm.com
>

> TL;DR -- Apparently fixed upstream in dhcpcd-9.5.0 or later (-10.0.0 available)

Probably one of the many fixes that 9.5.0 and up include, but that I
could not cherry-pick for Debian's 9.4.1.

Ideally, I would have shipped 9.5.0 with Bookworm, but upstream's
protracted failure at producing a release in a timely manner, despite
repeated requests from myself and others, means that it came out WAY
past the deadline for the Bookworm freeze.

> While dhcpcd5/dhcpcd runs and obtains leases, the -U / --dumplease function fails with either
> "Bad system call" or, if running under sudo, with "dhcpcd_readdumptimeout"
>

> The issue appears to be impacting other systems that have later versions of libc
> than does Debian Bullseye. Searching the upstream dhcpcd archive revealed
>
> <https://github.com/NetworkConfiguration/dhcpcd/issues/159>
>
> was reported by a user on Arch Linux, dhcpcd version 9.4.1 and glibc version 2.36
>
> rsmarples indicates "Fixed in dhcpcd-9.5.0"
>
> His comment appears to be roughly coincident with the release of dhcpcd-10.0.0

Release 10 got pushed right after 9.5.0 and isn't significantly
different from it.

> Building form upstream source at dhcpcd-10.0.0, without the Debian patches
>
> ./configure --prefix=/opt
> make
> sudo make install
>
> and replacing the running version with the local build restores the -U functionality.

Noted.

In principle, I have version 10 ready to upload. However, given the
Bookworm freeze, the best I could do is push it to experimental.

Martin-Éric

[Jeff Kletsky]

On 4/15/23 11:11 PM, Martin-Éric Racine wrote:

> [...]

> Noted.
>
> In principle, I have version 10 ready to upload. However, given the
> Bookworm freeze, the best I could do is push it to experimental.

Thanks for your time and efforts on this.

I did not realize that Bookworm's development cycle had progressed that far.

With the package functional for its primary use and a work-around
available, that seems like a very reasonable course of action.

[Shengjing Zhu]

The relevant fix is https://github.com/NetworkConfiguration/dhcpcd/commit/38befd4e