The `openssh` and `openssh_hpn` packages are now built without
the Kerberos support by default in an effort to reduce the attack surface.
The Kerberos support is likely used only by a fraction of the total users
(I'm guessing mainly users integrating SSH in an Active Directory env) so
dropping it should not impact too many users. It should also be noted that
the Kerberos/GSSAPI auth is disabled by default in the configuration.
`opensshWithKerberos` and `openssh_hpnWithKerberos` are added in order
to provide an easy migration path for users needing this support.
The `openssh_gssapi` package is kept untouched.
# Motivation
So far it was not possible to configure sshd to allow password authentication only for a specific user. This is because in the generated config a `Match User xxx` section would be required before the global `PasswordAuthentication` is defined, as otherwise the global option always takes precedence.
The same problem occurs with multiple other options under `settings`.
# Done
This PR fixes that issue for all settings by simply allowing them to be overridden with `null`, which leads to a removal of that setting from the config.
The user can then correctly configure user specific settings using extraConfig, like this:
```
Match User user1
PasswordAuthentication yes
Match all
PasswordAuthentication no
```
Motivation: Allow the sshd package to be built differently to the ssh
package (programs.ssh.package). For example, build sshd(1) without
openssl, but built ssh(1) with OpenSSL support.
Set the default to be programs.ssh.package, to preserve compatibility.
these changes were generated with nixq 0.0.2, by running
nixq ">> lib.mdDoc[remove] Argument[keep]" --batchmode nixos/**.nix
nixq ">> mdDoc[remove] Argument[keep]" --batchmode nixos/**.nix
nixq ">> Inherit >> mdDoc[remove]" --batchmode nixos/**.nix
two mentions of the mdDoc function remain in nixos/, both of which
are inside of comments.
Since lib.mdDoc is already defined as just id, this commit is a no-op as
far as Nix (and the built manual) is concerned.
Noticed that issue while reviewing #275633: when declaring
`ListenAddress host` without a port, all ports declared by
`Port`/`cfg.ports` will be used with `host` according to
`sshd_config(5)`.
However, if this is done and socket activation is used, only a socket
for port 22 is created instead of a sockets for each port from
`Port`/`cfg.ports`. This patch corrects that behavior.
Also added a regression test for this case.
When using e.g. `{ addr = "[::]"; port = 22; }` at `listenAddresses`,
the check fails because of an escaping issue[1] with
last 1 log lines:
> Invalid test mode specification -f
For full logs, run 'nix log /nix/store/c6pbpw5hjkjgipmarwyic9zyqr1xaix5-check-sshd-config.drv'
Using `lib.escapeShellArg` appears to solve the problem.
[1] https://github.com/NixOS/nixpkgs/pull/256090#issuecomment-1738063528
With this commit, the validation of `sshd_config`
is performed with `sshd -G` instead of `sshd -t`.
The former does not require a valid host key.
Checking the host key was never useful for us:
We just generated a dummy host key to
make the validation mechanism happy.
With this change the dummy key is no longer needed.
This change not only saves some CPU cycles
(avoid the generation of an RSA key),
but it also permits to set `RequiredRSASize` to a value
larger than the current rsa key default size (3072).
mkAliasOptionModule should not default to mdDoc descriptions because
that can break out-of-tree users of documentation infrastructure. add an
explicitly-MD variant for now, to be removed some time after the MD
transition is complete.
now nix-doc-munge will not introduce whitespace changes when it replaces
manpage references with the MD equivalent.
no change to the manpage, changes to the HTML manual are whitespace only.
make (almost) all links appear on only a single line, with no
unnecessary whitespace, using double quotes for attributes. this lets us
automatically convert them to markdown easily.
the few remaining links are extremely long link in a gnome module, we'll
come back to those at a later date.
our xslt already replaces double line breaks with a paragraph close and
reopen. not using explicit para tags lets nix-doc-munge convert more
descriptions losslessly.
only whitespace changes to generated documents, except for two
strongswan options gaining paragraph two breaks they arguably should've
had anyway.
the conversion procedure is simple:
- find all things that look like options, ie calls to either `mkOption`
or `lib.mkOption` that take an attrset. remember the attrset as the
option
- for all options, find a `description` attribute who's value is not a
call to `mdDoc` or `lib.mdDoc`
- textually convert the entire value of the attribute to MD with a few
simple regexes (the set from mdize-module.sh)
- if the change produced a change in the manual output, discard
- if the change kept the manual unchanged, add some text to the
description to make sure we've actually found an option. if the
manual changes this time, keep the converted description
this procedure converts 80% of nixos options to markdown. around 2000
options remain to be inspected, but most of those fail the "does not
change the manual output check": currently the MD conversion process
does not faithfully convert docbook tags like <code> and <package>, so
any option using such tags will not be converted at all.
If a host key file is a symlink pointing to an as of yet non-existent
file, we don't want to remove it, but instead follow the symlink and
create the file at that location.
See https://github.com/nix-community/impermanence/issues/101 for more
information on the issue the original behavior creates.
Introduced in OpenSSH 9.0 it became the part of the default kexAlgorithm
selection, visibile in sshd_config(5).
It is also enabled by default in the OpenSSH client, as can be seen from
$ ssh -Q KexAlgorithms
Also clarifies that we use the referenced documents as the lower bound,
given that they haven't been updated for 5-7y.
In a previous PR [1], the conditional to generate a new host key file
was changed to also include the case when the file exists, but has zero
size. This could occur when the system is uncleanly powered off shortly
after first boot.
However, ssh-keygen prompts the user before overwriting a file. For
example:
$ touch hi
$ ssh-keygen -f hi
Generating public/private rsa key pair.
hi already exists.
Overwrite (y/n)?
So, lets just try to remove the empty file (if it exists) before running
ssh-keygen.
[1] https://github.com/NixOS/nixpkgs/pull/141258
