The abort needs havePrivateMountNs == false AND /nix/store still ro:
remountReadOnlyWritable() returns early while the store is writable. Nix
<= 2.34 left it rw until reboot; 2.35 remounts in a private namespace, so
only a freshly booted host hits it. The repro command also uses an open-only
exec 7<..., since cat fails on the read even when the open succeeds.
While here, trim the comments and drop the disabled default_deny/nix
policies plus the explicit killUnconfinedConfinables=false (nixpkgs
default). 82 -> 34 lines.
Nix 2.35's root nix-env -- used by nixos-rebuild to set the system profile --
calls saveMountNamespace(), which opens /proc/self/ns/mnt before remounting
the read-only /nix/store writable. Those magic links have no connected path,
so AppArmor cannot match them against any rule and denies the open with
EACCES even in complain mode. The private mount namespace is then never
created and nixos-rebuild aborts with:
cannot remount "/nix/store" writable: not in a private mount namespace
Adding flags=(attach_disconnected) lets AppArmor re-root those paths on / so
the existing `file /**` rule matches. This also fixes any other sudo'd tool
that needs namespaces (unshare, nsenter, bwrap, ...).
Rolling this out to a host that already has the old profile loaded needs one
deploy with --no-reexec, so the current system's Nix performs nix-env --set
instead of the new system's; after that generation is active, plain
`just niri` works and the Nix version is never rolled back.
The broad 'file /** rwlkUx' rule conflicts with rix exec rules pulled in
via nested abstractions (xdg-open): AppArmor 5.0 rejects merged rules
with differing exec modifiers, failing apparmor.service on first load.
* security: make firewall secure-by-default, disable explicitly on servers
Flip the base firewall default to ON so new hosts are protected by default. Servers keep the firewall off (trusted internal LAN, WAN protected at the router) via explicit overrides in modules/nixos/server/{server,server-aarch64}.nix. Behavior-preserving for all 18 current hosts; adds a security-firewall eval test guarding the per-host state.
* test: fix security-firewall eval test to scalar per-host values
* security: enable AppArmor (complain) on all Linux hosts
* security: bind aquamarine metrics exporters to loopback
* security: restrict k3s kubeconfig file mode to 600
* security: disable SSH X11 forwarding on servers, keep on desktops
* security: add conservative systemd hardening to aquamarine services
* docs(apparmor): correct FHS-alias comment (nixpkgs has no broad FHS layer)
nixpkgs only creates /run/current-system, /usr/bin/env and /bin/sh; it does not
provide a broad FHS->store alias tree, so FHS-oriented abstractions are incomplete
on NixOS. They are safe only because the profiles run in complain mode.
* fix(aquamarine): scrape same-host exporters over loopback
The v2ray/postgres/sftpgo exporters were bound to 127.0.0.1 but VictoriaMetrics
scraped them via the host's routable IP, so those scrapes refused connections.
Point the three same-host scrape targets at 127.0.0.1 (VM runs on the same host).
node-exporter keeps the host IP since it binds 0.0.0.0.
* Revert "security: add conservative systemd hardening to aquamarine services"
This reverts commit f9cf99dadb.
ryan4yin | 二花
Ryan Yin