The family gate (decisions 63/64, R-780): family members with their own logins, a permanent forwardAuth door per family app, anchored exceptions, min_controller

- internal/family: the family list (bcrypt, generated 4x4 passwords shown once) + 30-day sessions in family.json (0600, atomic); a reset (generation), a removal or a logout ends sessions at the next request. - internal/stacks/family_gate.go: family_gate / family_gate_except / min_controller in .felhom.yml; the door is written BEFORE the first start (install and a removed app's restore), a life record in app.yaml, reconciled by the gate loop; priority below the install hold, setup gate and sign-up block; every exception anchored ^/prefix(/|$) (finding F1). - internal/web/family_gate.go: forwardAuth /__felhom_gate/family (app cookie felhom_famgate, host-only, names a store session); /__family/start|login|logout on the dashboard host (session cookie felhom_family, Path=/__family); sign-in counted per visitor (clientIP) AND per name, short windows; the household's dashboard session vouches. RequireAuth never reads a family cookie. The "Család" card on the security page: add / new password / remove. Red-proofs RP-F1..RP-F7 (felhom.eu audits/family-gate-2026-10-02/A/). Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_0159rPz1ZhFKsS53msqPYxtS
2026-10-02 07:42:47 +02:00
parent a4a753b9e2
commit 977665d8c0
25 changed files with 2168 additions and 10 deletions
@@ -0,0 +1,327 @@
+// Package family is the household's family list for the permanent family gate (`09` §3 decisions 63, 64; R-780).
+//
+// Each family member has their OWN name and password (never the dashboard's); the household's dashboard admin adds,
+// resets and removes them. A member who signs in gets a SESSION (30 days). Every app cookie the gate mints names the
+// session, so the gate asks this store on every request: a removed member, a reset password (the member's generation
+// moves on) or a logout (the session is deleted) ends every app's access at the next request.
+//
+// A session with Member "" is the HOUSEHOLD's: minted when the dashboard's own session vouched for the browser (the
+// setup gate's rule, decision 46). It is never a dashboard session and never opens the dashboard.
+//
+// Persisted as family.json (0600, tmp+fsync+rename) in the controller's data dir, so the controller's own backup and
+// restore carry it and a restart keeps every session. Hashes only — a password is shown once, when it is made.
+// Pinned by internal/family/family_test.go.
+package family
+
+import (
+	"crypto/rand"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"math/big"
+	"os"
+	"path/filepath"
+	"regexp"
+	"sort"
+	"sync"
+	"time"
+
+	"golang.org/x/crypto/bcrypt"
+)
+
+// SessionLife is how long a family sign-in lasts.
+const SessionLife = 30 * 24 * time.Hour
+
+// Member is one family member. Gen moves on at every password reset, ending the member's earlier sessions.
+type Member struct {
+	Name    string `json:"name"`
+	Hash    string `json:"hash"`
+	Gen     int    `json:"gen"`
+	Created string `json:"created"`
+}
+
+// Session is one sign-in. Member "" = the household (a dashboard session vouched for the browser).
+type Session struct {
+	ID     string    `json:"id"`
+	Member string    `json:"member"`
+	Gen    int       `json:"gen"`
+	Exp    time.Time `json:"exp"`
+}
+
+type file struct {
+	Members  []Member  `json:"members"`
+	Sessions []Session `json:"sessions"`
+}
+
+// Store is the family list and its sessions. A nil *Store answers "nobody" to every question.
+type Store struct {
+	path string
+	now  func() time.Time
+	cost int
+
+	dummyOnce sync.Once
+	dummy     []byte
+
+	mu       sync.Mutex
+	members  map[string]*Member
+	sessions map[string]Session
+}
+
+var (
+	ErrBadName  = errors.New("a name is 1-32 characters: lower-case letters, digits, dot, dash, underscore; starting with a letter or digit")
+	ErrExists   = errors.New("a member with that name already exists")
+	ErrNoMember = errors.New("no member with that name")
+)
+
+var nameRE = regexp.MustCompile(`^[a-z0-9][a-z0-9._-]{0,31}$`)
+
+// Open loads (or starts) the store at dir/family.json. A file that cannot be parsed is an error, never an empty list:
+// an empty list would silently lock every member out, and a rewrite would destroy the household's list.
+func Open(dir string) (*Store, error) {
+	s := &Store{path: filepath.Join(dir, "family.json"), now: time.Now, cost: bcrypt.DefaultCost,
+		members: map[string]*Member{}, sessions: map[string]Session{}}
+	b, err := os.ReadFile(s.path)
+	if errors.Is(err, os.ErrNotExist) {
+		return s, nil
+	}
+	if err != nil {
+		return nil, err
+	}
+	var f file
+	if err := json.Unmarshal(b, &f); err != nil {
+		return nil, fmt.Errorf("family.json unreadable: %w", err)
+	}
+	for i := range f.Members {
+		m := f.Members[i]
+		s.members[m.Name] = &m
+	}
+	for _, se := range f.Sessions {
+		s.sessions[se.ID] = se
+	}
+	return s, nil
+}
+
+// SetClock and SetCost are test seams.
+func (s *Store) SetClock(f func() time.Time) { s.now = f }
+func (s *Store) SetCost(c int)              { s.cost = c }
+
+func (s *Store) saveLocked() error {
+	f := file{Members: []Member{}, Sessions: []Session{}}
+	for _, m := range s.members {
+		f.Members = append(f.Members, *m)
+	}
+	sort.Slice(f.Members, func(i, j int) bool { return f.Members[i].Name < f.Members[j].Name })
+	now := s.now()
+	for id, se := range s.sessions {
+		if now.After(se.Exp) {
+			delete(s.sessions, id)
+			continue
+		}
+		f.Sessions = append(f.Sessions, se)
+	}
+	sort.Slice(f.Sessions, func(i, j int) bool { return f.Sessions[i].ID < f.Sessions[j].ID })
+	b, err := json.MarshalIndent(f, "", "  ")
+	if err != nil {
+		return err
+	}
+	tmp := s.path + ".tmp"
+	fh, err := os.OpenFile(tmp, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0o600)
+	if err != nil {
+		return err
+	}
+	if _, err := fh.Write(b); err != nil {
+		fh.Close()
+		return err
+	}
+	if err := fh.Sync(); err != nil {
+		fh.Close()
+		return err
+	}
+	if err := fh.Close(); err != nil {
+		return err
+	}
+	return os.Rename(tmp, s.path)
+}
+
+// pwAlphabet leaves out look-alikes (0/o, 1/l/i).
+const pwAlphabet = "abcdefghjkmnpqrstuvwxyz23456789"
+
+// newPassword is 4 groups of 4 from pwAlphabet (~79 bits), easy to read aloud and type on a phone.
+func newPassword() string {
+	out := make([]byte, 0, 19)
+	for g := 0; g < 4; g++ {
+		if g > 0 {
+			out = append(out, '-')
+		}
+		for i := 0; i < 4; i++ {
+			n, _ := rand.Int(rand.Reader, big.NewInt(int64(len(pwAlphabet))))
+			out = append(out, pwAlphabet[n.Int64()])
+		}
+	}
+	return string(out)
+}
+
+// Add makes a member with a generated password, returned once.
+func (s *Store) Add(name string) (string, error) {
+	if !nameRE.MatchString(name) {
+		return "", ErrBadName
+	}
+	pw := newPassword()
+	h, err := bcrypt.GenerateFromPassword([]byte(pw), s.cost)
+	if err != nil {
+		return "", err
+	}
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if _, ok := s.members[name]; ok {
+		return "", ErrExists
+	}
+	s.members[name] = &Member{Name: name, Hash: string(h), Gen: 1, Created: s.now().UTC().Format(time.RFC3339)}
+	if err := s.saveLocked(); err != nil {
+		delete(s.members, name)
+		return "", err
+	}
+	return pw, nil
+}
+
+// Reset gives a member a new generated password (returned once) and ends every earlier session of theirs.
+func (s *Store) Reset(name string) (string, error) {
+	pw := newPassword()
+	h, err := bcrypt.GenerateFromPassword([]byte(pw), s.cost)
+	if err != nil {
+		return "", err
+	}
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	m, ok := s.members[name]
+	if !ok {
+		return "", ErrNoMember
+	}
+	old := *m
+	m.Hash, m.Gen = string(h), m.Gen+1
+	s.dropSessionsLocked(name)
+	if err := s.saveLocked(); err != nil {
+		*m = old
+		return "", err
+	}
+	return pw, nil
+}
+
+// Remove deletes a member and every session of theirs.
+func (s *Store) Remove(name string) error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if _, ok := s.members[name]; !ok {
+		return ErrNoMember
+	}
+	delete(s.members, name)
+	s.dropSessionsLocked(name)
+	return s.saveLocked()
+}
+
+func (s *Store) dropSessionsLocked(name string) {
+	for id, se := range s.sessions {
+		if se.Member == name {
+			delete(s.sessions, id)
+		}
+	}
+}
+
+// Names lists the members, sorted.
+func (s *Store) Names() []string {
+	if s == nil {
+		return nil
+	}
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	out := make([]string, 0, len(s.members))
+	for n := range s.members {
+		out = append(out, n)
+	}
+	sort.Strings(out)
+	return out
+}
+
+// Verify checks a member's password. An unknown name costs a bcrypt compare too, so timing does not tell names apart.
+func (s *Store) Verify(name, password string) bool {
+	if s == nil {
+		return false
+	}
+	s.mu.Lock()
+	m, ok := s.members[name]
+	hash := ""
+	if ok {
+		hash = m.Hash
+	}
+	s.mu.Unlock()
+	if !ok {
+		s.dummyOnce.Do(func() { s.dummy, _ = bcrypt.GenerateFromPassword([]byte(newPassword()), s.cost) })
+		_ = bcrypt.CompareHashAndPassword(s.dummy, []byte(password))
+		return false
+	}
+	return bcrypt.CompareHashAndPassword([]byte(hash), []byte(password)) == nil
+}
+
+// NewSession starts a session for member ("" = the household). It refuses a member who does not exist.
+func (s *Store) NewSession(member string) (string, error) {
+	if s == nil {
+		return "", ErrNoMember
+	}
+	b := make([]byte, 24)
+	if _, err := rand.Read(b); err != nil {
+		return "", err
+	}
+	id := hex.EncodeToString(b)
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	gen := 0
+	if member != "" {
+		m, ok := s.members[member]
+		if !ok {
+			return "", ErrNoMember
+		}
+		gen = m.Gen
+	}
+	s.sessions[id] = Session{ID: id, Member: member, Gen: gen, Exp: s.now().Add(SessionLife)}
+	if err := s.saveLocked(); err != nil {
+		delete(s.sessions, id)
+		return "", err
+	}
+	return id, nil
+}
+
+// Valid reports whether a session still holds: it exists, has not expired, and — for a member — the member still
+// exists at the generation the session was made in.
+func (s *Store) Valid(id string) (Session, bool) {
+	if s == nil || id == "" {
+		return Session{}, false
+	}
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	se, ok := s.sessions[id]
+	if !ok || s.now().After(se.Exp) {
+		return Session{}, false
+	}
+	if se.Member != "" {
+		m, ok := s.members[se.Member]
+		if !ok || m.Gen != se.Gen {
+			return Session{}, false
+		}
+	}
+	return se, true
+}
+
+// EndSession deletes a session (logout). Unknown ids are not an error.
+func (s *Store) EndSession(id string) error {
+	if s == nil {
+		return nil
+	}
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if _, ok := s.sessions[id]; !ok {
+		return nil
+	}
+	delete(s.sessions, id)
+	return s.saveLocked()
+}