4eca20bd94
Cold-start unlock wrapped the database key under the credential *public* key.
A public key is public: mavweb writes it verbatim to passkeys.json, normally in
the same state dir as db_key.wrapped, so anyone holding both files recovered the
database key offline with no authenticator involved. The wrapped blob was a
plaintext key with extra steps.
The secret is now the WebAuthn PRF extension output — 32 bytes the authenticator
computes over a fixed salt and never stores anywhere. The blob gains a version:
v2: "MVNKW2\x00" || salt || nonce || AES-256-GCM(key), magic as AAD
v1: salt || nonce || AES-256-GCM(key) (read-only)
v1 still opens so an existing deployment is not bricked, and reports itself so
the daemon can log a SECURITY line telling him to re-enroll. Nothing writes v1.
The magic is authenticated, so a v2 blob cannot be stripped and re-read as v1.
Four other defects on the same path:
- The locked-boot store was opened on an IPC goroutine inside UnlockFn and
never closed. Close is what re-encrypts the tmpfs working copy back over
the ciphertext, so every write of a cold-started session was lost silently
on the next boot. daemonLock now owns the store and seals it at shutdown.
- MethodUnlock was reachable by anything on the box; the socket is same-uid
and cannot authenticate its caller. It now requires a passkey assertion
that mavweb verified first.
- Concurrent unlocks would each open a store and wire a daemon. One at a
time, and never a second one.
- The hand-rolled HKDF keyed the expand step with the salt instead of the
PRK. Replaced with crypto/hkdf.
Key wrapping moves from enrolment to the first assertion, because create() does
not produce a PRF result on most authenticators — only a support flag. An
authenticator without PRF now writes no wrapped file at all rather than one
that looks protected and is not, and the page says so.
Verified: make build, make test. New tests cover the v2 round trip, a wrong
secret, every single-bit tamper, truncation, the v1 downgrade attempt, legacy
v1 reads, non-32-byte and all-zero secrets, the ipc wire field, locked-mode
default-deny, a forged assertion never reaching the unlock path, seal-on-
shutdown after a cold start, and that nothing in the state dir contains the
plaintext key. The PRF round trip against real hardware is a QA step.
Vikunja #14
125 lines
4.2 KiB
Go
125 lines
4.2 KiB
Go
package ipc
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import (
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"bytes"
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"context"
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"encoding/json"
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"errors"
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"testing"
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)
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// The wire must carry the PRF secret, not the credential public key. This is
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// the field rename that fixes Vikunja #14: a v1 deployment sent "public_key",
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// and the value it sent was in passkeys.json next to the wrapped blob.
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func TestUnlockWireCarriesSecret(t *testing.T) {
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secret := bytes.Repeat([]byte{7}, 32)
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for _, p := range []any{unlockReq{Secret: secret}, storeEncryptionKeyReq{Secret: secret}} {
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b, err := json.Marshal(p)
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if err != nil {
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t.Fatalf("marshal %T: %v", p, err)
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}
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var m map[string]any
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if err := json.Unmarshal(b, &m); err != nil {
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t.Fatalf("unmarshal %T: %v", p, err)
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}
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if _, ok := m["secret"]; !ok {
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t.Errorf("%T has no \"secret\" field: %s", p, b)
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}
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if _, ok := m["public_key"]; ok {
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t.Errorf("%T still sends \"public_key\": %s", p, b)
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}
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}
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}
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// The secret must reach the daemon hook byte-for-byte through the socket.
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func TestUnlockDeliversSecretToHook(t *testing.T) {
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_, srv, cli, _ := newServerWithStore(t)
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secret := make([]byte, 32)
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for i := range secret {
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secret[i] = byte(i + 1)
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}
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var gotUnlock, gotWrap []byte
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srv.UnlockFn = func(_ context.Context, s []byte) error { gotUnlock = bytes.Clone(s); return nil }
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srv.WrapKeyFn = func(_ context.Context, s []byte) error { gotWrap = bytes.Clone(s); return nil }
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ctx := context.Background()
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if err := cli.Unlock(ctx, secret); err != nil {
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t.Fatalf("Unlock: %v", err)
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}
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if !bytes.Equal(gotUnlock, secret) {
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t.Errorf("UnlockFn got %x, want %x", gotUnlock, secret)
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}
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if err := cli.StoreEncryptionKey(ctx, secret); err != nil {
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t.Fatalf("StoreEncryptionKey: %v", err)
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}
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if !bytes.Equal(gotWrap, secret) {
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t.Errorf("WrapKeyFn got %x, want %x", gotWrap, secret)
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}
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}
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// A refusal from the daemon hook — a wrong passkey, or no prior assertion —
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// must surface to the caller as an error, never be swallowed into success.
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func TestUnlockPropagatesRefusal(t *testing.T) {
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_, srv, cli, _ := newServerWithStore(t)
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srv.UnlockFn = func(context.Context, []byte) error {
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return errors.New("unlock: no verified passkey assertion (assert first)")
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}
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if err := cli.Unlock(context.Background(), bytes.Repeat([]byte{9}, 32)); err == nil {
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t.Fatal("a refused unlock reported success")
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}
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}
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// Without the hooks wired — the normal, unencrypted deployment — both methods
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// answer ErrUnknownMethod rather than pretending to have done something.
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func TestUnlockUnwiredIsUnknownMethod(t *testing.T) {
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_, _, cli, _ := newServerWithStore(t)
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ctx := context.Background()
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if err := cli.Unlock(ctx, bytes.Repeat([]byte{1}, 32)); err == nil {
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t.Error("Unlock succeeded with no UnlockFn wired")
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}
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if err := cli.StoreEncryptionKey(ctx, bytes.Repeat([]byte{1}, 32)); err == nil {
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t.Error("StoreEncryptionKey succeeded with no WrapKeyFn wired")
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}
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}
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// Locked mode: Server.Check is the whole authorization surface, and it must
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// default-deny everything except the two methods the unlock flow needs.
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func TestLockedCheckDefaultDenies(t *testing.T) {
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_, srv, cli, _ := newServerWithStore(t)
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locked := errors.New("locked")
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srv.Check = func(_ context.Context, m Method, _ json.RawMessage) error {
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switch m {
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case MethodAssertStepUp, MethodUnlock:
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return nil
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default:
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return locked
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}
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}
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unlocked := false
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srv.UnlockFn = func(context.Context, []byte) error { unlocked = true; return nil }
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srv.StepUp = func(context.Context) error { return nil }
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srv.WrapKeyFn = func(context.Context, []byte) error { return nil }
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ctx := context.Background()
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// A store method must be refused while locked.
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if _, err := cli.RecentNotes(ctx, 5); err == nil {
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t.Error("a store read went through while locked")
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}
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// Key wrapping is NOT on the allowlist: a locked daemon has no key to wrap.
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if err := cli.StoreEncryptionKey(ctx, bytes.Repeat([]byte{2}, 32)); err == nil {
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t.Error("StoreEncryptionKey was allowed while locked")
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}
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// The unlock flow itself must still work.
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if err := cli.AssertStepUp(ctx); err != nil {
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t.Errorf("AssertStepUp refused while locked: %v", err)
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}
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if err := cli.Unlock(ctx, bytes.Repeat([]byte{3}, 32)); err != nil {
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t.Errorf("Unlock refused while locked: %v", err)
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}
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if !unlocked {
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t.Error("UnlockFn never ran")
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}
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}
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