[Pkg-libvirt-maintainers] Bug#977728: /usr/bin/virsh: Please pass XDG_* environment variables to the SSH binary

[Guilhem Moulin]

Package: libvirt-clients
Version: 6.9.0-1+b2
Severity: wishlist
File: /usr/bin/virsh
Tags: patch upstream

Dear Maintainer,

Since version 8.4 OpenSSH supports environment variables in several
configuration values [0], thereby allowing using $XDG_RUNTIME_DIR as
ControlPath directory without having to hardcode its value in
~/.ssh/config:

    ControlPath ${XDG_RUNTIME_DIR}/ssh-%C

However the above snippet causes the command to fail as virsh runs it in
a sanitized environment:

    error: failed to connect to the hypervisor
    error: Cannot recv data: vdollar_percent_expand: env var ${XDG_RUNTIME_DIR} has no value
    invalid environment variable expansion: Connection reset by peer

This patch preserves environment variables of the XDG Base Directory
Specification [1] when calling the SSH binary.  (Other XDG_* environment
variables are arguably useful as well for ProxyCommand.)

Alternatively, maybe a configuration option to run the SSH binary in the
stock environment would do?  After all OpenSSH has its own environment
sanitation logic.

Thanks,
cheers,
-- 
Guilhem.

[0] https://www.openssh.com/txt/release-8.4 https://bugzilla.mindrot.org/show_bug.cgi?id=3140
[1] https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html#variables

-- System Information:
Debian Release: bullseye/sid
  APT prefers unstable
  APT policy: (500, 'unstable'), (1, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 5.9.0-3-amd64 (SMP w/8 CPU threads)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=en_US:en
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages libvirt-clients depends on:
ii  libc6           2.31-6
ii  libgcc-s1       10.2.1-1
ii  libglib2.0-0    2.66.4-1
ii  libreadline8    8.1-1
ii  libvirt0        6.9.0-1+b2
ii  libxml2         2.9.10+dfsg-6.3+b1
ii  sensible-utils  0.0.12+nmu1

libvirt-clients recommends no packages.

Versions of packages libvirt-clients suggests:
ii  libvirt-daemon  6.9.0-1+b2

-- no debconf information
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