tailscale/tka/sig_test.go

634 lines
19 KiB
Go

// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
package tka
import (
"crypto/ed25519"
"reflect"
"testing"
"github.com/google/go-cmp/cmp"
"github.com/google/go-cmp/cmp/cmpopts"
"tailscale.com/types/key"
"tailscale.com/types/tkatype"
)
func TestSigDirect(t *testing.T) {
node := key.NewNode()
nodeKeyPub, _ := node.Public().MarshalBinary()
// Verification key (the key used to sign)
pub, priv := testingKey25519(t, 1)
k := Key{Kind: Key25519, Public: pub, Votes: 2}
sig := NodeKeySignature{
SigKind: SigDirect,
KeyID: k.MustID(),
Pubkey: nodeKeyPub,
}
sigHash := sig.SigHash()
sig.Signature = ed25519.Sign(priv, sigHash[:])
if sig.SigHash() != sigHash {
t.Errorf("sigHash changed after signing: %x != %x", sig.SigHash(), sigHash)
}
if err := sig.verifySignature(node.Public(), k); err != nil {
t.Fatalf("verifySignature() failed: %v", err)
}
// Test verification fails when verifying for a different node
if err := sig.verifySignature(key.NewNode().Public(), k); err == nil {
t.Error("verifySignature() did not error for different nodekey")
}
// Test verification fails if the wrong verification key is provided
copy(k.Public, []byte{1, 2, 3, 4})
if err := sig.verifySignature(node.Public(), k); err == nil {
t.Error("verifySignature() did not error for wrong verification key")
}
}
func TestSigNested(t *testing.T) {
// Network-lock key (the key used to sign the nested sig)
pub, priv := testingKey25519(t, 1)
k := Key{Kind: Key25519, Public: pub, Votes: 2}
// Rotation key (the key used to sign the outer sig)
rPub, rPriv := testingKey25519(t, 2)
// The old node key which is being rotated out
oldNode := key.NewNode()
oldPub, _ := oldNode.Public().MarshalBinary()
// The new node key that is being rotated in
node := key.NewNode()
nodeKeyPub, _ := node.Public().MarshalBinary()
// The original signature for the old node key, signed by
// the network-lock key.
nestedSig := NodeKeySignature{
SigKind: SigDirect,
KeyID: k.MustID(),
Pubkey: oldPub,
WrappingPubkey: rPub,
}
sigHash := nestedSig.SigHash()
nestedSig.Signature = ed25519.Sign(priv, sigHash[:])
if err := nestedSig.verifySignature(oldNode.Public(), k); err != nil {
t.Fatalf("verifySignature(oldNode) failed: %v", err)
}
if l := sigChainLength(nestedSig); l != 1 {
t.Errorf("nestedSig chain length = %v, want 1", l)
}
// The signature authorizing the rotation, signed by the
// rotation key & embedding the original signature.
sig := NodeKeySignature{
SigKind: SigRotation,
Pubkey: nodeKeyPub,
Nested: &nestedSig,
}
sigHash = sig.SigHash()
sig.Signature = ed25519.Sign(rPriv, sigHash[:])
if err := sig.verifySignature(node.Public(), k); err != nil {
t.Fatalf("verifySignature(node) failed: %v", err)
}
if l := sigChainLength(sig); l != 2 {
t.Errorf("sig chain length = %v, want 2", l)
}
// Test verification fails if the wrong verification key is provided
kBad := Key{Kind: Key25519, Public: []byte{1, 2, 3, 4}, Votes: 2}
if err := sig.verifySignature(node.Public(), kBad); err == nil {
t.Error("verifySignature() did not error for wrong verification key")
}
// Test verification fails if the inner signature is invalid
tmp := make([]byte, ed25519.SignatureSize)
copy(tmp, nestedSig.Signature)
copy(nestedSig.Signature, []byte{1, 2, 3, 4})
if err := sig.verifySignature(node.Public(), k); err == nil {
t.Error("verifySignature(node) succeeded with bad inner signature")
}
copy(nestedSig.Signature, tmp)
// Test verification fails if the outer signature is invalid
copy(sig.Signature, []byte{1, 2, 3, 4})
if err := sig.verifySignature(node.Public(), k); err == nil {
t.Error("verifySignature(node) succeeded with bad outer signature")
}
// Test verification fails if the outer signature is signed with a
// different public key to whats specified in WrappingPubkey
sig.Signature = ed25519.Sign(priv, sigHash[:])
if err := sig.verifySignature(node.Public(), k); err == nil {
t.Error("verifySignature(node) succeeded with different signature")
}
}
func TestSigNested_DeepNesting(t *testing.T) {
// Network-lock key (the key used to sign the nested sig)
pub, priv := testingKey25519(t, 1)
k := Key{Kind: Key25519, Public: pub, Votes: 2}
// Rotation key (the key used to sign the outer sig)
rPub, rPriv := testingKey25519(t, 2)
// The old node key which is being rotated out
oldNode := key.NewNode()
oldPub, _ := oldNode.Public().MarshalBinary()
// The original signature for the old node key, signed by
// the network-lock key.
nestedSig := NodeKeySignature{
SigKind: SigDirect,
KeyID: k.MustID(),
Pubkey: oldPub,
WrappingPubkey: rPub,
}
sigHash := nestedSig.SigHash()
nestedSig.Signature = ed25519.Sign(priv, sigHash[:])
if err := nestedSig.verifySignature(oldNode.Public(), k); err != nil {
t.Fatalf("verifySignature(oldNode) failed: %v", err)
}
outer := nestedSig
var lastNodeKey key.NodePrivate
for range 15 { // 15 = max nesting level for CBOR
lastNodeKey = key.NewNode()
nodeKeyPub, _ := lastNodeKey.Public().MarshalBinary()
tmp := outer
sig := NodeKeySignature{
SigKind: SigRotation,
Pubkey: nodeKeyPub,
Nested: &tmp,
}
sigHash = sig.SigHash()
sig.Signature = ed25519.Sign(rPriv, sigHash[:])
outer = sig
}
if err := outer.verifySignature(lastNodeKey.Public(), k); err != nil {
t.Fatalf("verifySignature(lastNodeKey) failed: %v", err)
}
// Test this works with our public API
a, _ := Open(newTestchain(t, "G1\nG1.template = genesis",
optTemplate("genesis", AUM{MessageKind: AUMCheckpoint, State: &State{
Keys: []Key{k},
DisablementSecrets: [][]byte{DisablementKDF([]byte{1, 2, 3})},
}})).Chonk())
if err := a.NodeKeyAuthorized(lastNodeKey.Public(), outer.Serialize()); err != nil {
t.Errorf("NodeKeyAuthorized(lastNodeKey) failed: %v", err)
}
// Test verification fails if the inner signature is invalid
tmp := make([]byte, ed25519.SignatureSize)
copy(tmp, nestedSig.Signature)
copy(nestedSig.Signature, []byte{1, 2, 3, 4})
if err := outer.verifySignature(lastNodeKey.Public(), k); err == nil {
t.Error("verifySignature(lastNodeKey) succeeded with bad inner signature")
}
copy(nestedSig.Signature, tmp)
// Test verification fails if an intermediate signature is invalid
copy(outer.Nested.Nested.Signature, []byte{1, 2, 3, 4})
if err := outer.verifySignature(lastNodeKey.Public(), k); err == nil {
t.Error("verifySignature(lastNodeKey) succeeded with bad outer signature")
}
}
func TestSigCredential(t *testing.T) {
// Network-lock key (the key used to sign the nested sig)
pub, priv := testingKey25519(t, 1)
k := Key{Kind: Key25519, Public: pub, Votes: 2}
// 'credential' key (the one being delegated to)
cPub, cPriv := testingKey25519(t, 2)
// The node key being certified
node := key.NewNode()
nodeKeyPub, _ := node.Public().MarshalBinary()
// The signature certifying delegated trust to another
// public key.
nestedSig := NodeKeySignature{
SigKind: SigCredential,
KeyID: k.MustID(),
WrappingPubkey: cPub,
}
sigHash := nestedSig.SigHash()
nestedSig.Signature = ed25519.Sign(priv, sigHash[:])
// The signature authorizing the node key, signed by the
// delegated key & embedding the original signature.
sig := NodeKeySignature{
SigKind: SigRotation,
Pubkey: nodeKeyPub,
Nested: &nestedSig,
}
sigHash = sig.SigHash()
sig.Signature = ed25519.Sign(cPriv, sigHash[:])
if err := sig.verifySignature(node.Public(), k); err != nil {
t.Fatalf("verifySignature(node) failed: %v", err)
}
// Test verification fails if the wrong verification key is provided
kBad := Key{Kind: Key25519, Public: []byte{1, 2, 3, 4}, Votes: 2}
if err := sig.verifySignature(node.Public(), kBad); err == nil {
t.Error("verifySignature() did not error for wrong verification key")
}
// Test someone can't misuse our public API for verifying node-keys
a, _ := Open(newTestchain(t, "G1\nG1.template = genesis",
optTemplate("genesis", AUM{MessageKind: AUMCheckpoint, State: &State{
Keys: []Key{k},
DisablementSecrets: [][]byte{DisablementKDF([]byte{1, 2, 3})},
}})).Chonk())
if err := a.NodeKeyAuthorized(node.Public(), nestedSig.Serialize()); err == nil {
t.Error("NodeKeyAuthorized(SigCredential, node) did not fail")
}
// but that they can use it properly (nested in a SigRotation)
if err := a.NodeKeyAuthorized(node.Public(), sig.Serialize()); err != nil {
t.Errorf("NodeKeyAuthorized(SigRotation{SigCredential}, node) failed: %v", err)
}
// Test verification fails if the inner signature is invalid
tmp := make([]byte, ed25519.SignatureSize)
copy(tmp, nestedSig.Signature)
copy(nestedSig.Signature, []byte{1, 2, 3, 4})
if err := sig.verifySignature(node.Public(), k); err == nil {
t.Error("verifySignature(node) succeeded with bad inner signature")
}
copy(nestedSig.Signature, tmp)
// Test verification fails if the outer signature is invalid
copy(tmp, sig.Signature)
copy(sig.Signature, []byte{1, 2, 3, 4})
if err := sig.verifySignature(node.Public(), k); err == nil {
t.Error("verifySignature(node) succeeded with bad outer signature")
}
copy(sig.Signature, tmp)
// Test verification fails if we attempt to check a different node-key
otherNode := key.NewNode()
if err := sig.verifySignature(otherNode.Public(), k); err == nil {
t.Error("verifySignature(otherNode) succeeded with different principal")
}
// Test verification fails if the outer signature is signed with a
// different public key to whats specified in WrappingPubkey
sig.Signature = ed25519.Sign(priv, sigHash[:])
if err := sig.verifySignature(node.Public(), k); err == nil {
t.Error("verifySignature(node) succeeded with different signature")
}
}
func TestSigSerializeUnserialize(t *testing.T) {
nodeKeyPub := []byte{1, 2, 3, 4}
pub, priv := testingKey25519(t, 1)
key := Key{Kind: Key25519, Public: pub, Votes: 2}
sig := NodeKeySignature{
SigKind: SigDirect,
KeyID: key.MustID(),
Pubkey: nodeKeyPub,
Nested: &NodeKeySignature{
SigKind: SigDirect,
KeyID: key.MustID(),
Pubkey: nodeKeyPub,
},
}
sigHash := sig.SigHash()
sig.Signature = ed25519.Sign(priv, sigHash[:])
var decoded NodeKeySignature
if err := decoded.Unserialize(sig.Serialize()); err != nil {
t.Fatalf("Unserialize() failed: %v", err)
}
if diff := cmp.Diff(sig, decoded); diff != "" {
t.Errorf("unmarshalled version differs (-want, +got):\n%s", diff)
}
}
func TestNodeKeySignatureRotationDetails(t *testing.T) {
// Trusted network lock key
pub, priv := testingKey25519(t, 1)
k := Key{Kind: Key25519, Public: pub, Votes: 2}
// 'credential' key (the one being delegated to)
cPub, cPriv := testingKey25519(t, 2)
n1, n2, n3 := key.NewNode(), key.NewNode(), key.NewNode()
n1pub, _ := n1.Public().MarshalBinary()
n2pub, _ := n2.Public().MarshalBinary()
n3pub, _ := n3.Public().MarshalBinary()
tests := []struct {
name string
nodeKey key.NodePublic
sigFn func() NodeKeySignature
want *RotationDetails
}{
{
name: "SigDirect",
nodeKey: n1.Public(),
sigFn: func() NodeKeySignature {
s := NodeKeySignature{
SigKind: SigDirect,
KeyID: pub,
Pubkey: n1pub,
}
sigHash := s.SigHash()
s.Signature = ed25519.Sign(priv, sigHash[:])
return s
},
want: nil,
},
{
name: "SigWrappedCredential",
nodeKey: n1.Public(),
sigFn: func() NodeKeySignature {
nestedSig := NodeKeySignature{
SigKind: SigCredential,
KeyID: pub,
WrappingPubkey: cPub,
}
sigHash := nestedSig.SigHash()
nestedSig.Signature = ed25519.Sign(priv, sigHash[:])
sig := NodeKeySignature{
SigKind: SigRotation,
Pubkey: n1pub,
Nested: &nestedSig,
}
sigHash = sig.SigHash()
sig.Signature = ed25519.Sign(cPriv, sigHash[:])
return sig
},
want: &RotationDetails{
InitialSig: &NodeKeySignature{
SigKind: SigCredential,
KeyID: pub,
WrappingPubkey: cPub,
},
},
},
{
name: "SigRotation",
nodeKey: n2.Public(),
sigFn: func() NodeKeySignature {
nestedSig := NodeKeySignature{
SigKind: SigDirect,
Pubkey: n1pub,
KeyID: pub,
WrappingPubkey: cPub,
}
sigHash := nestedSig.SigHash()
nestedSig.Signature = ed25519.Sign(priv, sigHash[:])
sig := NodeKeySignature{
SigKind: SigRotation,
Pubkey: n2pub,
Nested: &nestedSig,
}
sigHash = sig.SigHash()
sig.Signature = ed25519.Sign(cPriv, sigHash[:])
return sig
},
want: &RotationDetails{
InitialSig: &NodeKeySignature{
SigKind: SigDirect,
Pubkey: n1pub,
KeyID: pub,
WrappingPubkey: cPub,
},
PrevNodeKeys: []key.NodePublic{n1.Public()},
},
},
{
name: "SigRotationNestedTwice",
nodeKey: n3.Public(),
sigFn: func() NodeKeySignature {
initialSig := NodeKeySignature{
SigKind: SigDirect,
Pubkey: n1pub,
KeyID: pub,
WrappingPubkey: cPub,
}
sigHash := initialSig.SigHash()
initialSig.Signature = ed25519.Sign(priv, sigHash[:])
prevRotation := NodeKeySignature{
SigKind: SigRotation,
Pubkey: n2pub,
Nested: &initialSig,
}
sigHash = prevRotation.SigHash()
prevRotation.Signature = ed25519.Sign(cPriv, sigHash[:])
sig := NodeKeySignature{
SigKind: SigRotation,
Pubkey: n3pub,
Nested: &prevRotation,
}
sigHash = sig.SigHash()
sig.Signature = ed25519.Sign(cPriv, sigHash[:])
return sig
},
want: &RotationDetails{
InitialSig: &NodeKeySignature{
SigKind: SigDirect,
Pubkey: n1pub,
KeyID: pub,
WrappingPubkey: cPub,
},
PrevNodeKeys: []key.NodePublic{n2.Public(), n1.Public()},
},
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
if tt.want != nil {
initialHash := tt.want.InitialSig.SigHash()
tt.want.InitialSig.Signature = ed25519.Sign(priv, initialHash[:])
}
sig := tt.sigFn()
if err := sig.verifySignature(tt.nodeKey, k); err != nil {
t.Fatalf("verifySignature(node) failed: %v", err)
}
got, err := sig.rotationDetails()
if err != nil {
t.Fatal(err)
}
if !reflect.DeepEqual(got, tt.want) {
t.Errorf("rotationDetails() = %v, want %v", got, tt.want)
}
})
}
}
func TestDecodeWrappedAuthkey(t *testing.T) {
k, isWrapped, sig, priv := DecodeWrappedAuthkey("tskey-32mjsdkdsffds9o87dsfkjlh", nil)
if want := "tskey-32mjsdkdsffds9o87dsfkjlh"; k != want {
t.Errorf("decodeWrappedAuthkey(<unwrapped-key>).key = %q, want %q", k, want)
}
if isWrapped {
t.Error("decodeWrappedAuthkey(<unwrapped-key>).isWrapped = true, want false")
}
if sig != nil {
t.Errorf("decodeWrappedAuthkey(<unwrapped-key>).sig = %v, want nil", sig)
}
if priv != nil {
t.Errorf("decodeWrappedAuthkey(<unwrapped-key>).priv = %v, want nil", priv)
}
k, isWrapped, sig, priv = DecodeWrappedAuthkey("tskey-auth-k7UagY1CNTRL-ZZZZZ--TLpAEDA1ggnXuw4/fWnNWUwcoOjLemhOvml1juMl5lhLmY5sBUsj8EWEAfL2gdeD9g8VDw5tgcxCiHGlEb67BgU2DlFzZApi4LheLJraA+pYjTGChVhpZz1iyiBPD+U2qxDQAbM3+WFY0EBlggxmVqG53Hu0Rg+KmHJFMlUhfgzo+AQP6+Kk9GzvJJOs4-k36RdoSFqaoARfQo0UncHAV0t3YTqrkD5r/z2jTrE43GZWobnce7RGD4qYckUyVSF+DOj4BA/r4qT0bO8kk6zg", nil)
if want := "tskey-auth-k7UagY1CNTRL-ZZZZZ"; k != want {
t.Errorf("decodeWrappedAuthkey(<wrapped-key>).key = %q, want %q", k, want)
}
if !isWrapped {
t.Error("decodeWrappedAuthkey(<wrapped-key>).isWrapped = false, want true")
}
if sig == nil {
t.Fatal("decodeWrappedAuthkey(<wrapped-key>).sig = nil, want non-nil signature")
}
sigHash := sig.SigHash()
if !ed25519.Verify(sig.KeyID, sigHash[:], sig.Signature) {
t.Error("signature failed to verify")
}
// Make sure the private is correct by using it.
someSig := ed25519.Sign(priv, []byte{1, 2, 3, 4})
if !ed25519.Verify(sig.WrappingPubkey, []byte{1, 2, 3, 4}, someSig) {
t.Error("failed to use priv")
}
}
func TestResignNKS(t *testing.T) {
// Tailnet lock keypair of a signing node.
authPub, authPriv := testingKey25519(t, 1)
authKey := Key{Kind: Key25519, Public: authPub, Votes: 2}
// Node's own tailnet lock key used to sign rotation signatures.
tlPriv := key.NewNLPrivate()
// The original (oldest) node key, signed by a signing node.
origNode := key.NewNode()
origPub, _ := origNode.Public().MarshalBinary()
// The original signature for the old node key, signed by
// the network-lock key.
directSig := NodeKeySignature{
SigKind: SigDirect,
KeyID: authKey.MustID(),
Pubkey: origPub,
WrappingPubkey: tlPriv.Public().Verifier(),
}
sigHash := directSig.SigHash()
directSig.Signature = ed25519.Sign(authPriv, sigHash[:])
if err := directSig.verifySignature(origNode.Public(), authKey); err != nil {
t.Fatalf("verifySignature(origNode) failed: %v", err)
}
// Generate a bunch of node keys to be used by tests.
var nodeKeys []key.NodePublic
for range 20 {
n := key.NewNode()
nodeKeys = append(nodeKeys, n.Public())
}
// mkSig creates a signature chain starting with a direct signature
// with rotation signatures matching provided keys (from the nodeKeys slice).
mkSig := func(prevKeyIDs ...int) tkatype.MarshaledSignature {
sig := &directSig
for _, i := range prevKeyIDs {
pk, _ := nodeKeys[i].MarshalBinary()
sig = &NodeKeySignature{
SigKind: SigRotation,
Pubkey: pk,
Nested: sig,
}
var err error
sig.Signature, err = tlPriv.SignNKS(sig.SigHash())
if err != nil {
t.Error(err)
}
}
return sig.Serialize()
}
tests := []struct {
name string
oldSig tkatype.MarshaledSignature
wantPrevNodeKeys []key.NodePublic
}{
{
name: "first-rotation",
oldSig: directSig.Serialize(),
wantPrevNodeKeys: []key.NodePublic{origNode.Public()},
},
{
name: "second-rotation",
oldSig: mkSig(0),
wantPrevNodeKeys: []key.NodePublic{nodeKeys[0], origNode.Public()},
},
{
name: "truncate-chain",
oldSig: mkSig(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14),
wantPrevNodeKeys: []key.NodePublic{
nodeKeys[14],
nodeKeys[13],
nodeKeys[12],
nodeKeys[11],
nodeKeys[10],
nodeKeys[9],
nodeKeys[8],
nodeKeys[7],
nodeKeys[6],
nodeKeys[5],
nodeKeys[4],
nodeKeys[3],
nodeKeys[2],
nodeKeys[1],
origNode.Public(),
},
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
newNode := key.NewNode()
got, err := ResignNKS(tlPriv, newNode.Public(), tt.oldSig)
if err != nil {
t.Fatalf("ResignNKS() error = %v", err)
}
var gotSig NodeKeySignature
if err := gotSig.Unserialize(got); err != nil {
t.Fatalf("Unserialize() failed: %v", err)
}
if err := gotSig.verifySignature(newNode.Public(), authKey); err != nil {
t.Errorf("verifySignature(newNode) error: %v", err)
}
rd, err := gotSig.rotationDetails()
if err != nil {
t.Fatalf("rotationDetails() error = %v", err)
}
if sigChainLength(gotSig) != len(tt.wantPrevNodeKeys)+1 {
t.Errorf("sigChainLength() = %v, want %v", sigChainLength(gotSig), len(tt.wantPrevNodeKeys)+1)
}
if diff := cmp.Diff(tt.wantPrevNodeKeys, rd.PrevNodeKeys, cmpopts.EquateComparable(key.NodePublic{})); diff != "" {
t.Errorf("PrevNodeKeys mismatch (-want +got):\n%s", diff)
}
})
}
}
func sigChainLength(s NodeKeySignature) int {
if s.Nested != nil {
return 1 + sigChainLength(*s.Nested)
}
return 1
}