With `sshd -t` config validation for SSH is possible. Until now, the
config generated by Nix was applied without any validation (which is
especially a problem for advanced config like `Match` blocks).
When deploying broken ssh config with nixops to a remote machine it gets
even harder to fix the problem due to the broken ssh that makes reverts
with nixops impossible.
This change performs the validation in a Nix build environment by
creating a store path with the config and generating a mocked host key
which seems to be needed for the validation. With a broken config, the
deployment already fails during the build of the derivation.
The original attempt was done in #56345 by adding a submodule for Match
groups to make it harder screwing that up, however that made the module
far more complex and config should be described in an easier way as
described in NixOS/rfcs#42.
Release notes are available at https://www.openssh.com/txt/release-7.5.
Mostly a bugfix release, no major backwards-incompatible changes.
Remove deprecated `UsePrivilegeSeparation` option,
which is now mandatory.
AFAICT, this issue only occurs when sshd is socket-activated. It turns
out that the preStart script's stdout and stderr are connected to the
socket, not just the main command's. So explicitly connect stderr to
the journal and redirect stdout to stderr.
This reverts commit 1a74eedd07. It
breaks NixOps, which expects that
rm -f /etc/ssh/ssh_host_ed25519_key*
systemctl restart sshd
cat /etc/ssh/ssh_host_ed25519_key.pub
works.
The configuration { services.openssh.enable = true;
services.openssh.forwardX11 = false; } caused
programs.ssh.setXAuthLocation to be set to false, which was not the
intent. The intent is that programs.ssh.setXAuthLocation should be
automatically enabled if needed or if xauth is already available.
This reverts commit a8eb2a6a81. OpenSSH
7.0 is causing too many interoperability problems so soon before the
15.08 release.
For instance, it causes NixOps EC2 initial deployments to fail with
"REMOTE HOST IDENTIFICATION HAS CHANGED". This is because the client
knows the server's ssh-dss host key, but this key is no longer
accepted by default. Setting "HostKeyAlgorithms" to "+ssh-dss" does
not work because it causes ssh-dss to be ordered after
"ecdsa-sha2-nistp521", which the server also offers. (Normally, ssh
prioritizes host key algorithms for which the client has a known host
key, but not if you set HostKeyAlgorithms.)
The man page for ssh-keygen(1) has a section "MODULI GENERATION" that describes
how to generate your own moduli file. The following script might also be helpful:
| #! /usr/bin/env bash
|
| moduliFiles=()
|
| generateModuli()
| {
| ssh-keygen -G "moduli-$1.candidates" -b "$1"
| ssh-keygen -T "moduli-$1" -f "moduli-$1.candidates"
| rm "moduli-$1.candidates"
| }
|
| for (( i=0 ; i <= 16 ; ++i )); do
| let bitSize="2048 + i * 128"
| generateModuli "$bitSize" &
| moduliFiles+=( "moduli-$bitSize" )
| done
| wait
|
| echo >moduli "# Time Type Tests Tries Size Generator Modulus"
| cat >>moduli "${moduliFiles[@]}"
| rm "${moduliFiles[@]}"
Note that generating moduli takes a long time, i.e. several hours on a fast
machine!
This patch resolves https://github.com/NixOS/nixpkgs/pull/5870.
