Bug#1135654: openssh-client: Option WarnWeakCrypto no not accepted, upgrade to backports

Package: openssh-client
Version: 1:10.2p1-6~bpo13+1
Severity: normal
X-Debbugs-Cc: [email protected]

Dear Maintainer,

When connecting to my local git repo on a Synology NAS I received the following warning:

> $ git pull
> ** WARNING: connection is not using a post-quantum key exchange algorithm.
> ** This session may be vulnerable to "store now, decrypt later" attacks.
> ** The server may need to be upgraded. See https://openssh.com/pq.html

There is a way to turn off this (annoying) warning, namely to
put a section in ~/.ssh/config:

> Match host mygitserver
>  WarnWeakCrypto no

However, when using openssh 1:10.0p1-7+deb13u2 from Trixie
stable-security, I got the following error, which made git
abort:

> .ssh/config: line 19: Bad configuration option: warnweakcrypto

My other computers did not complain about WarnWeakCrypto, so I
upgraded openssh on my machine to the version in Trixie backports
1:10.2p1-6~bpo13+1 and the problem went away.

Solution
========

Maintainers
-----------
Push an update of openssh to the version in backports.

Users
-----
1) Activate the backports repository in /etc/apt/sources.list.d/debian.sources
2) In /etc/apt/preferences.d place a file backports.pref with the following content:

Package: openssh-*
Pin: release n=trixie-backports
Pin-Priority: 900


Maintainers, thanks for your work!


-- System Information:
Debian Release: 13.4
  APT prefers stable-updates
  APT policy: (500, 'stable-updates'), (500, 'stable-security'), (500, 'stable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 6.12.74+deb13+1-amd64 (SMP w/16 CPU threads; PREEMPT)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8) (ignored: LC_ALL set to en_GB.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 openssh-client depends on:
ii  init-system-helpers         1.69~deb13u1
ii  libc6                       2.41-12+deb13u2
ii  libedit2                    3.1-20250104-1
ii  libfido2-1                  1.15.0-1+b1
ii  libgssapi-krb5-2            1.21.3-5
ii  libselinux1                 3.8.1-1
ii  libssl3t64                  3.5.5-1~deb13u2
ii  systemd [systemd-sysusers]  257.9-1~deb13u1
ii  zlib1g                      1:1.3.dfsg+really1.3.1-1+b1

Versions of packages openssh-client recommends:
ii  xauth  1:1.1.2-1.1

Versions of packages openssh-client suggests:
pn  keychain                   <none>
ii  ksshaskpass [ssh-askpass]  4:6.3.4-1
pn  libpam-ssh                 <none>
pn  monkeysphere               <none>

-- no debconf information