Source: openssh
Version: 1:10.5p1-1
Severity: serious
Justification: Policy 10.7.4
Hi,
If openssh-server is purged after openssh-server-gssapi is installed,
the postrm script unconditionally removes configuration which it thinks
still belongs to openssh-server, while in fact, openssh-server-gssapi
has become the owner of that configuration. The deleted files involve
the host keys, sshd_config, and systemd unit activation, rendering the SSH
service unusable. openssh-client/openssh-client-gssapi has a similar problem,
although it is less severe.
Initial state:
root@host:/etc# dpkg -l | grep openssh
rc openssh-client 1:10.4p1-4
amd64 secure shell (SSH) client, for secure access to remote
machines
ii openssh-client-gssapi 1:10.5p1-1
amd64 secure shell (SSH) client, with GSS-API support
ii openssh-common 1:10.5p1-1
amd64 common files for OpenSSH
rc openssh-server 1:10.4p1-4
amd64 secure shell (SSH) server, for secure access from
remote machines
ii openssh-server-gssapi 1:10.5p1-1
amd64 secure shell (SSH) server, with GSS-API key exchange
ii openssh-sftp-server 1:10.5p1-1
amd64 secure shell (SSH) sftp server module, for SFTP access
from remote machines
root@host:/etc# dpkg -L openssh-client
/etc
/etc/ssh
root@host:/etc# dpkg -L openssh-server
/etc
/etc/default
/etc/init.d
/etc/pam.d
/etc/ssh
/etc/ssh/sshd_config.d
/etc/sv
/etc/sv/ssh
/etc/sv/ssh/.meta
/etc/sv/ssh/log
/etc/ufw
/etc/ufw/applications.d
Configuration lost after purging openssh-client:
root@host:/etc# dpkg --purge openssh-client
(Reading database… 233916 files and directories currently installed.)
Purging configuration files for openssh-client (1:10.4p1-4)…
root@host:/etc# git status
On branch master
Changes not staged for commit:
(use "git add/rm <file>..." to update what will be committed)
(use "git restore <file>..." to discard changes in working directory)
deleted: ssh/moduli
deleted: systemd/user/sockets.target.wants/ssh-agent.socket
no changes added to commit (use "git add" and/or "git commit -a")
Configuration lost after purging openssh-server:
root@host:/etc# git restore ssh/moduli
systemd/user/sockets.target.wants/ssh-agent.socket
root@host:/etc# dpkg --purge openssh-server
(Reading database… 233916 files and directories currently installed.)
Purging configuration files for openssh-server (1:10.4p1-4)…
root@host:/etc# git status
On branch master
Changes not staged for commit:
(use "git add/rm <file>..." to update what will be committed)
(use "git restore <file>..." to discard changes in working directory)
deleted: rc2.d/S03ssh
deleted: rc3.d/S03ssh
deleted: rc4.d/S03ssh
deleted: rc5.d/S03ssh
deleted: runit/runsvdir/default/ssh
deleted: ssh/ssh_host_ed25519_key
deleted: ssh/ssh_host_ed25519_key.pub
deleted: ssh/ssh_host_rsa_key
deleted: ssh/ssh_host_rsa_key.pub
deleted: ssh/sshd_config
deleted: systemd/system/multi-user.target.wants/ssh.service
deleted: systemd/system/ssh.service.wants/sshd-keygen.service
deleted: systemd/system/ssh.socket.wants/sshd-keygen.service
deleted: systemd/system/sshd.service
deleted: systemd/system/sshd.service.wants/sshd-keygen.service
deleted: systemd/system/[email protected]/sshd-keygen.service
no changes added to commit (use "git add" and/or "git commit -a")
IMHO the best way to solve this issue would be introducing
openssh-client-common and openssh-server-common packages, and moving all
the common configurationt to those packages.
Regards,
Gabor
-- System Information:
Debian Release: forky/sid
APT prefers testing
APT policy: (990, 'testing'), (102, 'unstable')
Architecture: amd64 (x86_64)
Kernel: Linux 7.2.5-gg (SMP w/8 CPU threads; PREEMPT)
Locale: LANG=en_US.utf8, LC_CTYPE=en_US.utf8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
