While at it (see previous commit), using attrNames in combination with
length is a bit verbose for checking whether the filtered attribute set
is empty, so let's just compare it against an empty attribute set.
Signed-off-by: aszlig <aszlig@nix.build>
When generating values for the services.nsd.zones attribute using values
from pkgs, we'll run into an infinite recursion because the nsd module
has a condition on the top-level definition of nixpkgs.config.
While it would work to push the definition a few levels down, it will
still only work if we don't use bind tools for generating zones.
As far as I could see, Python support for BIND seems to be only needed
for the dnssec-* tools, so instead of using nixpkgs.config, we now
directly override pkgs.bind instead of globally in nixpkgs.
To illustrate the problem with a small test case, instantiating the
following Nix expression from the nixpkgs source root will cause the
mentioned infinite recursion:
(import ./nixos {
configuration = { lib, pkgs, ... }: {
services.nsd.enable = true;
services.nsd.zones = import (pkgs.writeText "foo.nix" ''
{ "foo.".data = "xyz";
"foo.".dnssec = true;
}
'');
};
}).vm
With this change, generating zones via import-from-derivation is now
possible again.
Signed-off-by: aszlig <aszlig@nix.build>
Cc: @pngwjpgh
This adds a NixOS option for setting the CPU max and min frequencies
with `cpufreq`. The two options that have been added are:
- `powerManagement.cpufreq.max`
- `powerManagement.cpufreq.min`
It also adds an alias to the `powerManagement.cpuFreqGovernor` option as
`powerManagement.cpufreq.governor`. This updates the installer to use
the new option name. It also updates the manual with a note about
the new name.
For the hardened profile disable symmetric multi threading. There seems to be
no *proven* method of exploiting cache sharing between threads on the same CPU
core, so this may be considered quite paranoid, considering the perf cost.
SMT can be controlled at runtime, however. This is in keeping with OpenBSD
defaults.
TODO: since SMT is left to be controlled at runtime, changing the option
definition should take effect on system activation. Write to
/sys/devices/system/cpu/smt/control
For the hardened profile enable flushing whenever the hypervisor enters the
guest, but otherwise leave at kernel default (conditional flushing as of
writing).
Introduces the option security.protectKernelImage that is intended to control
various mitigations to protect the integrity of the running kernel
image (i.e., prevent replacing it without rebooting).
This makes sense as a dedicated module as it is otherwise somewhat difficult
to override for hardened profile users who want e.g., hibernation to work.
The aim is to minimize surprises: when the user explicitly installs a
package in their configuration, it should override any package
implicitly installed by NixOS.
This, paired with the previous commit, ensures the channel won't be held
back from a kernel upgrade and a non-building sd image, while still
having a new-kernel variant available.
