Files
Arena Agent e060ec96eb fix(hub): make Hub login verification loadable and diagnosable
Correction to the patch-0002 report: after a reboot the Hub icon asks for a password AND the correct free (desktop) password is rejected there, while desktop sign-in accepts it. Patch 0002/0003 explain the icon prompt (legacy hub_manual_logout cookie; fixed in 0003), but the rejection itself means verify_system_password() never gets a conclusive crypt answer in the Hub unit and its PAM fallback cannot load either: on NixOS a bare libcrypt.so.1/libpam.so.0 resolves through LD_LIBRARY_PATH or not at all (or to glibc's failure-token stub), and until now every stage failed silently into a generic 'Incorrect password'.

password-model.nix now puts pkgs.libxcrypt and pkgs.pam on sovran-hub-web's LD_LIBRARY_PATH so both the crypt fallbacks and PAM can actually load. verify_system_password() now logs, journal-visible and never containing a password or hash: the shadow hash scheme, every libcrypt source tried and whether it loaded, and PAM's service + return code when it has to decide.
2026-10-18 21:39:41 -05:00

161 lines
8.8 KiB
Nix

{ config, pkgs, lib, ... }:
# Sovran_SystemsOS -- password model cleanup (GNOME 50 / gnome-keyring 50)
#
# * /etc/shadow is the only source of truth for authentication (Hub login == GDM login).
# * /var/lib/secrets/{free,root}-password are root-only DISPLAY copies for the Hub, written
# by exactly one module (system_password.py) and verified against shadow before shown.
# * The GNOME login keyring is decoupled from the login password: it is created with a
# blank password and pam_gnome_keyring never hands the login password to the daemon.
# => no "unlock your login keyring" prompts, ever (also on the autologin live ISO);
# Brave's cookie/password key survives every password change; no *.keyring wiping.
# * Legacy machines (password unknown to the Hub) are handled by the Hub's existing
# onboarding "migration password" step -- not by a boot service any more.
#
# Import from configuration.nix and DELETE these lines there:
# security.pam.services.gdm-password.enableGnomeKeyring = true;
# security.pam.services.gdm-autologin.enableGnomeKeyring = true;
# the four systemd.tmpfiles.rules for /home/free/.local/share/keyrings/{,default}
# and in modules/credentials.nix delete root-password-setup, free-password-setup,
# free-password-migration and the `rm -f /home/free/.local/share/keyrings/*.keyring` lines.
let
user = "free";
home = "/home/${user}";
# A login keyring with a blank password. gnome-keyring stores those in this textual
# format and auto-unlocks them on demand without any prompt (verified on 48; the rule in
# gkm-secret-collection.c that picks the textual format for a blank master is unchanged
# in 50 and the 50.0 release notes contain no behavioural changes).
blankLoginKeyring = pkgs.writeText "login.keyring" ''
[keyring]
display-name=login
ctime=0
mtime=0
lock-on-idle=false
lock-after=false
'';
# Which keyring gnome-keyring treats as the default collection. Without
# this pointer the daemon falls back to a keyring literally named
# "Default" (default.keyring), which is created encrypted and prompts
# "An application wants access to the keyring \"Default keyring\"" --
# e.g. Brave on Hub launch -- even though the login keyring is blank.
# The pre-cleanup configuration.nix seeded this file; password-model.nix
# dropped it by mistake.
defaultKeyringPointer = pkgs.writeText "keyring-default" ''
login
'';
# Apply the installer's plaintext password ONCE: only while the account still has no
# usable hash (nixos-install --no-root-password leaves both accounts locked). After that
# the file is display-only and the Hub (system_password.py) is the only thing that
# writes it. This replaces the old services, which re-applied the file on EVERY boot
# and silently reverted any password changed elsewhere.
# On already-installed machines the case below matches `*)` (real hash) -> no-op:
# an upgrade can never change or generate a password.
applyOnce = { account, fallback ? false }: ''
set -euo pipefail
f=/var/lib/secrets/${account}-password
hash="$(getent shadow ${account} | cut -d: -f2 || true)"
case "$hash" in
""|"!"*|"*"*)
if [ -s "$f" ] && ! grep -qE '^[0-9a-f]{32}:[0-9a-f]{64,}$' "$f"; then
echo "${account}:$(head -n1 "$f")" | chpasswd
${lib.optionalString fallback ''
else
# Installer left no usable file: generate one so GDM is always reachable
# (the user reads it in the Hub). Never runs once the account has a password.
W="apple barn brook cabin cedar cloud coral crane delta eagle ember fern field flame
flora flint frost grove haven hedge holly heron jade juniper kelp larch lemon lilac
linden loch lotus maple marsh meadow mist mossy mount oak ocean olive petal pine
pixel plum pond prism quartz raven ridge river robin rocky rose rowan sage sand
sierra silver slate snow solar spark spruce stone storm summit swift thorn tide
timber torch trout vale vault vine walnut wave willow wren"
pw=$(echo $W | tr ' ' '\n' | shuf -n4 | paste -sd- -)-$(printf '%02d' $((RANDOM % 100)))
umask 077; printf '%s\n' "$pw" > "$f"
echo "${account}:$pw" | chpasswd
''}
fi ;;
*) ;; # password already set: never touch it here again
esac
'';
in
{
# ── 1. Keyring: never learns the login password ───────────────────────────
# nixpkgs' gnome-keyring module turns this on for `login` (gdm-password includes it).
# If the daemon ever receives the login password it re-encrypts the blank keyring with
# it on the next save -- so it must be off everywhere.
security.pam.services.login.enableGnomeKeyring = lib.mkForce false;
security.pam.services.gdm-password.enableGnomeKeyring = lib.mkForce false;
security.pam.services.gdm-autologin.enableGnomeKeyring = lib.mkForce false;
security.pam.services.passwd.enableGnomeKeyring = lib.mkForce false;
# Seed the blank keyring. `C` copies only if the file does not exist, so an existing
# keyring is never overwritten -- which is also what makes a reset's `rm *.keyring`
# harmless: the next boot re-seeds a fresh blank keyring.
systemd.tmpfiles.rules = [
"d ${home}/.local 0700 ${user} users -"
"d ${home}/.local/share 0700 ${user} users -"
"d ${home}/.local/share/keyrings 0700 ${user} users -"
"C ${home}/.local/share/keyrings/login.keyring 0600 ${user} users - ${blankLoginKeyring}"
"C ${home}/.local/share/keyrings/default 0600 ${user} users - ${defaultKeyringPointer}"
];
# One-time migration for machines that already have a keyring encrypted with the
# (old) login password: move it aside and seed the blank one. Runs before GDM; the old
# file is kept. Same cost users pay today on every password change (Brave logs you out
# of sites once) -- but only once, ever.
system.activationScripts.sovranBlankKeyring = lib.stringAfter [ "users" ] ''
d=${home}/.local/share/keyrings
if [ -f "$d/login.keyring" ] && ! head -c 9 "$d/login.keyring" | grep -q '^\[keyring\]'; then
mv "$d/login.keyring" "$d/login.keyring.encrypted-$(date +%Y%m%d)"
install -o ${user} -g users -m 0600 ${blankLoginKeyring} "$d/login.keyring"
fi
# Machines that already lost the default pointer may also have picked up
# an encrypted "Default keyring" (default.keyring) that prompts on every
# application start (Brave/Hub). Point the default at the blank login
# keyring again, and move any encrypted Default keyring aside (kept,
# never deleted) so the prompt cannot come back.
if [ -d "$d" ]; then
if [ ! -f "$d/default" ] || ! grep -qx 'login' "$d/default"; then
install -o ${user} -g users -m 0600 ${defaultKeyringPointer} "$d/default"
fi
if [ -f "$d/default.keyring" ] && ! head -c 9 "$d/default.keyring" | grep -q '^\[keyring\]'; then
mv "$d/default.keyring" "$d/default.keyring.encrypted-$(date +%Y%m%d)"
fi
fi
'';
# ── 2. First-boot password hand-off (unit names kept: the Hub's "System Passwords"
# service card is bound to root-password-setup.service) ───────────────────────
systemd.services.free-password-setup = {
description = "Apply the installer's 'free' password (first boot only)";
wantedBy = [ "multi-user.target" ];
before = [ "display-manager.service" ];
serviceConfig = { Type = "oneshot"; RemainAfterExit = true; };
path = [ pkgs.shadow pkgs.coreutils pkgs.gnugrep pkgs.getent ];
script = applyOnce { account = user; fallback = true; };
};
systemd.services.root-password-setup = {
description = "Apply the installer's root password (first boot only)";
wantedBy = [ "multi-user.target" ];
serviceConfig = { Type = "oneshot"; RemainAfterExit = true; };
path = [ pkgs.shadow pkgs.coreutils pkgs.gnugrep pkgs.getent ];
script = applyOnce { account = "root"; };
};
# Legacy detection now lives in the Hub (system_password.ensure_migration_pending).
systemd.services.free-password-migration.enable = false;
# ── 3. The Hub verifies passwords against /etc/shadow via libxcrypt ───────
systemd.services.sovran-hub-web.environment.LIBCRYPT = "${pkgs.libxcrypt}/lib/libcrypt.so.1";
# ctypes fallback lookups (bare "libcrypt.so.1" / "libpam.so.0") resolve
# through LD_LIBRARY_PATH inside the unit. Without this they find nothing
# on NixOS (no ld.so.conf paths) or glibc's failure-token libcrypt stub,
# whose "*0"/NULL answers read as a wrong password at Hub login even
# though the same password signs in at the desktop. Put the real
# libxcrypt and PAM libraries on the Hub's library path.
systemd.services.sovran-hub-web.environment.LD_LIBRARY_PATH =
lib.makeLibraryPath [ pkgs.libxcrypt pkgs.pam ];
}