Files
nix-files/hosts/common/fs/remote-servo.nix

133 lines
5.1 KiB
Nix

{ config, lib, utils, ... }:
let
fsOpts = import ./fs-opts.nix;
commonOptions = fsOpts.ftp ++ fsOpts.noauto;
mountpoint = "/mnt/.servo_ftp";
systemdName = utils.escapeSystemdPath mountpoint;
device = "curlftpfs#ftp://servo-hn:/";
fsType = "fuse3";
options = commonOptions ++ [
# systemd (or maybe fuse?) swallows stderr of mount units with no obvious fix.
# instead, use this flag to log the mount output to disk
"stderr_path=/var/log/curlftpfs/servo-hn.stderr"
];
remoteServo = subdir: {
# sane.fs."/mnt/servo/${subdir}".mount.bind = "/mnt/.servo_ftp/${subdir}";
systemd.mounts = [{
where = "/mnt/servo/${subdir}";
what = "/mnt/.servo_ftp/${subdir}";
options = "bind,nofail";
type = "auto";
after = [ "${systemdName}.mount" ];
upheldBy = [ "${systemdName}.mount" ]; #< start this mount whenever the underlying becomes available
bindsTo = [ "${systemdName}.mount" ]; #< stop this mount whenever the underlying disappears
}];
};
in
lib.mkMerge [
{
sane.programs.curlftpfs.enableFor.system = true;
system.fsPackages = [
config.sane.programs.curlftpfs.package
];
sane.fs."/var/log/curlftpfs".dir.acl.mode = "0777";
fileSystems."/mnt/.servo_ftp" = {
inherit device fsType options;
noCheck = true;
};
systemd.mounts = [{
where = mountpoint;
what = device;
type = fsType;
options = lib.concatStringsSep "," options;
wantedBy = [ "default.target" ];
after = [ "network-online.target" ];
requires = [ "network-online.target" ];
#VVV patch so that when the mount fails, we start a timer to remount it.
# and for a disconnection after a good mount (onSuccess), restart the timer to be more aggressive
unitConfig.OnFailure = [ "${systemdName}.timer" ];
unitConfig.OnSuccess = [ "${systemdName}-restart-timer.target" ];
mountConfig.TimeoutSec = "10s";
mountConfig.ExecSearchPath = [ "/run/current-system/sw/bin" ];
mountConfig.User = "colin";
mountConfig.AmbientCapabilities = "CAP_SETPCAP CAP_SYS_ADMIN";
# hardening (systemd-analyze security mnt-servo-playground.mount)
mountConfig.CapabilityBoundingSet = "CAP_SETPCAP CAP_SYS_ADMIN";
mountConfig.LockPersonality = true;
mountConfig.MemoryDenyWriteExecute = true;
mountConfig.NoNewPrivileges = true;
mountConfig.ProtectClock = true;
mountConfig.ProtectHostname = true;
mountConfig.RemoveIPC = true;
mountConfig.RestrictAddressFamilies = "AF_UNIX AF_INET AF_INET6";
#VVV this includes anything it reads from, e.g. /bin/sh; /nix/store/...
# see `systemd-analyze filesystems` for a full list
mountConfig.RestrictFileSystems = "@common-block @basic-api fuse";
mountConfig.RestrictRealtime = true;
mountConfig.RestrictSUIDSGID = true;
mountConfig.SystemCallArchitectures = "native";
mountConfig.SystemCallFilter = [
"@system-service"
"@mount"
"~@chown"
"~@cpu-emulation"
"~@keyring"
# could remove almost all io calls, however one has to keep `open`, and `write`, to communicate with the fuse device.
# so that's pretty useless as a way to prevent write access
];
mountConfig.IPAddressDeny = "any";
mountConfig.IPAddressAllow = "10.0.10.5";
mountConfig.DevicePolicy = "closed"; # only allow /dev/{null,zero,full,random,urandom}
mountConfig.DeviceAllow = "/dev/fuse";
# mountConfig.RestrictNamespaces = true;
}];
systemd.targets."${systemdName}-restart-timer" = {
# hack unit which, when started, stops the timer (if running), and then starts it again.
after = [ "${systemdName}.timer" ];
conflicts = [ "${systemdName}.timer" ];
upholds = [ "${systemdName}.timer" ];
unitConfig.StopWhenUnneeded = true;
};
systemd.timers."${systemdName}" = {
timerConfig.Unit = "${systemdName}.mount";
timerConfig.AccuracySec = "2s";
timerConfig.OnActiveSec = [
# try to remount at these timestamps, backing off gradually
# there seems to be an implicit mount attempt at t=0.
"10s"
"30s"
"60s"
"120s"
];
# cap the backoff to a fixed interval.
timerConfig.OnUnitActiveSec = [ "120s" ];
};
}
# this granularity of servo media mounts is necessary to support sandboxing. consider:
# 1. servo offline
# 2. launch a long-running app
# 3. servo comes online
# in order for the servo mount to be propagated into the app's namespace, we need to bind
# the root mountpoint into the app namespace. if we wish to only grant the app selective access
# to servo, we must create *multiple* mountpoints: /mnt/servo/FOO directories which always exist,
# and are individually bound to /mnt/.servo_ftp/FOO as the latter becomes available.
(remoteServo "media/archive")
(remoteServo "media/Books")
(remoteServo "media/collections")
# (remoteServo "media/datasets")
(remoteServo "media/games")
(remoteServo "media/Music")
(remoteServo "media/Pictures/macros")
(remoteServo "media/torrents")
(remoteServo "media/Videos")
(remoteServo "playground")
]