With ‘systemd.user.units’ and ‘systemd.user.services’, you can specify
units used by per-user systemd instances. For example,
systemd.user.services.foo =
{ description = "foo";
wantedBy = [ "default.target" ];
serviceConfig.ExecStart = "${pkgs.foo}/bin/foo";
};
declares a unit ‘foo.service’ that gets started automatically when the
user systemd instance starts, and is stopped when the user systemd
instance stops.
Note that there is at most one systemd instance per user: it's created
when a user logs in and there is no systemd instance for that user
yet, and it's removed when the user fully logs out (i.e. has no
sessions anymore). So if you're simultaneously logged in via X11 and a
virtual console, you get only one copy of foo.
If you define a unit, and either systemd or a package in
systemd.packages already provides that unit, then we now generate a
file /etc/systemd/system/<unit>.d/overrides.conf. This makes it
possible to use upstream units, while allowing them to be customised
from the NixOS configuration. For instance, the module nix-daemon.nix
now uses the units provided by the Nix package. And all unit
definitions that duplicated upstream systemd units are finally gone.
This makes the baseUnit option unnecessary, so I've removed it.
This allows specifying rules for systemd-tmpfiles.
Also, enable systemd-tmpfiles-clean.timer so that stuff is cleaned up
automatically 15 minutes after boot and every day, *if* you have the
appropriate cleanup rules (which we don't have by default).
This creates static device nodes such as /dev/fuse or
/dev/snd/seq. The kernel modules for these devices will be loaded on
demand when the device node is opened.
This prevents insidious errors once systemd begins handling the unit. If
the unit is loaded at boot, any errors of this nature are logged to the
console before the journal service is running. This makes it very hard
to diagnose the issue. Therefore, this assertion helps guarantee the
mistake is not made.
Note that systemd no longer depends on dbus, so we're rid of the
cyclic dependency problem between systemd and dbus.
This commit incorporates from wkennington's systemd branch
(203dcff45002a63f6be75c65f1017021318cc839,
1f842558a95947261ece66f707bfa24faf5a9d88).
This mostly upgrades transmission, and does some very minor touchups on
AppArmor support.
In particular, there is now no need to ever specify the umask as part of
the settings, as it will be mixed in by default (which is essentially
always what you want). Also, the default configuration is now more
sensible: Downloads are put in /var/lib/transmission/Downloads, and
incomplete files are put in /var/lib/transmission/.incomplete - this
also allows easy use of file syncing probrams, like BitTorrent Sync.
Finally, this unconditionally enables the AppArmor profiles for the
daemon, if AppArmor is enabled - rather than letting the user specify
profile support, it's best to default to supporting profiles for daemons
transparently in all places.
Signed-off-by: Austin Seipp <aseipp@pobox.com>
Previously, if the currently installed Nix is too old to evaluate
Nixpkgs, then nixos-rebuild would fail and the user had to upgrade Nix
manually. Now, as a fallback, we run ‘nix-store -r’ to obtain a binary
Nix directly from the binary cache.
This allows doing any necessary actions that were not in the installed
nixos-rebuild (such as downloading a new version of Nix). This does
require us to be careful that nixos-rebuild is backwards-compatible
(i.e. can run in any old installation).
The style for IDs dictates that groups/users should have the same ID -
so if a user doesn't have a group or vice versa, then we should skip
that ID.
In this case, we had already assigned grsecurity GID 121, but I
accidentally also assigned Hydra UID 121. Instead, let's assign Hydra
UID 122. And also assign a GID (122) as well.
Luckily nobody was depending on this yet (except me).
Signed-off-by: Austin Seipp <aseipp@pobox.com>
Using pkgs.lib on the spine of module evaluation is problematic
because the pkgs argument depends on the result of module
evaluation. To prevent an infinite recursion, pkgs and some of the
modules are evaluated twice, which is inefficient. Using ‘with lib’
prevents this problem.
Previously we were setting GRKERNSEC_PROC_USER y, which was a little bit
too strict. It doesn't allow a special group (e.g. the grsecurity group
users) to access /proc information - this requires
GRKERNSEC_PROC_USERGROUP y, and the two are mutually exclusive.
This was also not in line with the default automatic grsecurity
configuration - it actually defaults to USERGROUP (although it has a
default GID of 1001 instead of ours), not USER.
This introduces a new option restrictProcWithGroup - enabled by default
- which turns on GRKERNSEC_PROC_USERGROUP instead. It also turns off
restrictProc by default and makes sure both cannot be enabled.
Signed-off-by: Austin Seipp <aseipp@pobox.com>
This module implements a significant refactoring in grsecurity
configuration for NixOS, making it far more usable by default and much
easier to configure.
- New security.grsecurity NixOS attributes.
- All grsec kernels supported
- Allows default 'auto' grsec configuration, or custom config
- Supports custom kernel options through kernelExtraConfig
- Defaults to high-security - user must choose kernel, server/desktop
mode, and any virtualisation software. That's all.
- kptr_restrict is fixed under grsecurity (it's unwriteable)
- grsecurity patch creation is now significantly abstracted
- only need revision, version, and SHA1
- kernel version requirements are asserted for sanity
- built kernels can have the uname specify the exact grsec version
for development or bug reports. Off by default (requires
`security.grsecurity.config.verboseVersion = true;`)
- grsecurity sysctl support
- By default, disabled.
- For people who enable it, NixOS deploys a 'grsec-lock' systemd
service which runs at startup. You are expected to configure sysctl
through NixOS like you regularly would, which will occur before the
service is started. As a result, changing sysctl settings requires
a reboot.
- New default group: 'grsecurity'
- Root is a member by default
- GRKERNSEC_PROC_GID is implicitly set to the 'grsecurity' GID,
making it possible to easily add users to this group for /proc
access
- AppArmor is now automatically enabled where it wasn't before, despite
implying features.apparmor = true
The most trivial example of enabling grsecurity in your kernel is by
specifying:
security.grsecurity.enable = true;
security.grsecurity.testing = true; # testing 3.13 kernel
security.grsecurity.config.system = "desktop"; # or "server"
This specifies absolutely no virtualisation support. In general, you
probably at least want KVM host support, which is a little more work.
So:
security.grsecurity.enable = true;
security.grsecurity.stable = true; # enable stable 3.2 kernel
security.grsecurity.config = {
system = "server";
priority = "security";
virtualisationConfig = "host";
virtualisationSoftware = "kvm";
hardwareVirtualisation = true;
}
This module has primarily been tested on Hetzner EX40 & VQ7 servers
using NixOps.
Signed-off-by: Austin Seipp <aseipp@pobox.com>
This prevents errors like "Another app is currently holding the
xtables lock" if the firewall and NAT services are starting in
parallel. (Longer term, we should probably move to a single service
for managing the iptables rules.)
