This is meant to replace /proc/sys/net/ipv4/conf/*/rp_filter, which
only works for ipv4. Furthermore, it's nicer to handle this kind of
filtering in the firewall.
There are some more subtle differences, please see:
https://home.regit.org/netfilter-en/secure-use-of-helpers/
I chose to enable this by default (when the firewall is enabled) as
it's a good idea in general. Only people with advanced routing needs
might not want this, but I guess they don't use the nixos firewall
anyway and use a custom solution. Furthermore, the option only becomes
available in kernel 3.3+, so conservative nixos users that just stick
to the default kernel will not need to act now just yet.
For each statically configured interface, we now create a unit
‘<interface>-cfg.service’ which gets started as soon as the network
device comes up. Similarly, each bridge defined in
‘networking.bridges’ and virtual interface in ‘networking.interfaces’
is created by a service ‘<interface>.service’.
So if we have
networking.bridges.br0.interfaces = [ "eth0" "eth1" ];
networking.interfaces =
[ { name = "br0";
ipAddress = "192.168.1.1";
}
];
then there will be a unit ‘br0.service’ that depends on
‘sys-subsystem-net-devices-eth0.device’ and
‘sys-subsystem-net-devices-eth1.device’, and a unit ‘br0-cfg.service’
that depends on ‘sys-subsystem-net-devices-br0.device’.
The special handling for cronjobs should probably move to the cron
module (logcheckIgnore = bool option) in the future, as it's more
natural to just declare a cronjob, and mark it as "log-ignored",
instead of adding cronjobs through logcheck.
But as systemCronjobs is not an attrset yet (just simple strings),
this would require adding an attrset for cronjobs or parsing strings
in the nix language to get hold of the cron-user and command.
So for now, I keep the interface within logcheck's module.
However SLIM is still broken and you have to create a
/usr/lib/dri/fglrx_dri.so symlink pointing to
/run/opengl-driver/lib/fglrx_dri.so
At least fgl_glxgears shows 10 times more frames per second now
The upower daemon needs the gdbus command (which is weird given that
upower links against dbus_glib, but ah well...). This fixes suspend
in KDE with systemd.
Alsa-utils provides a udev rule to restore volume settings, so use
that instead of restoring them from a systemd service. The
"alsa-store" service saves the settings on shutdown.
So instead of:
boot.systemd.services."foo".serviceConfig =
''
StartLimitInterval=10
CPUShare=500
'';
you can say:
boot.systemd.services."foo".serviceConfig.StartLimitInterval = 10;
boot.systemd.services."foo".serviceConfig.CPUShare = 500;
This way all unit options are available and users can set/override
options in configuration.nix.
This makes it easier for systemd to track it and avoids race conditions such as
this one:
systemd[1]: PID file /run/sshd.pid not readable (yet?) after start.
systemd[1]: Failed to start SSH Daemon.
systemd[1]: Unit sshd.service entered failed state.
systemd[1]: sshd.service holdoff time over, scheduling restart.
systemd[1]: Stopping SSH Daemon...
systemd[1]: Starting SSH Daemon...
sshd[2315]: Server listening on 0.0.0.0 port 22.
sshd[2315]: Server listening on :: port 22.
sshd[2335]: error: Bind to port 22 on 0.0.0.0 failed: Address already in use.
sshd[2335]: error: Bind to port 22 on :: failed: Address already in use.
sshd[2335]: fatal: Cannot bind any address.
systemd[1]: Started SSH Daemon.
When spamd isn't running as 'root', it cannot access the usual ~/.spamassassin
path where user-specific files normally reside. Instead, we use the path
/var/lib/spamassassin-<user> to store those home directories.
* Add group 'networkmanager' and implement polkit configuration
that allows users in this group to make persistent, system-wide
changes to NetworkManager settings.
* Add support for ModemManager. 3G modems should work out of the
box now (it does for me...). This introduces a dependency on
pkgs.modemmanager.
* Write NetworkManger config file to Nix store, and let the
daemon use it from there.
I had some problems with LDAP user lookups not working properly
at boot. I found that invalidating passwd and group on the
ip-up event (when nscd-invalidate starts) helped a bit.
Logind sessions are more generally useful than for device ownership.
For instances, ssh logins can be put in their own session (and thus
their own cgroup).
Subtle: dhcpcd.service would call resolvconf during shutdown, which in
turn would start invalidate-nscd.service, causing the shutdown to be
cancelled. Instead, give nscd.service a proper reload action, and do
"systemctl reload --no-block nscd.service". The --no-block is
necessary to prevent that command from waiting until a timeout occurs
(bug in systemd?).
This especially annoyed me whenver I was doing nixos-rebuild switch and getting
logged out on all consoles. With this there now is services.mingetty.dontRestart
for heavy VT users to deactivate this behaviour.
The option is disabled by default so that previously existing installations
aren't affected.
If you'd like to migrate to the fixed numeric id for Apache, set "fixUidAndGid
= true", edit the file "/etc/groups" and replace the old GID value with 54.
(NixOS can't do that for you because it refuses to change a GID that identifies
the primary group of a user.) Then run
find / -xdev -uid $oldUID -exec chown 54 {} +
find / -xdev -gid $oldGID -exec chgrp 54 {} +
to update ownership of all files that are supposed to be owned by Apache.
