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tailscale/tka/sig_test.go

302 lines
10 KiB
Go

// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package tka
import (
"crypto/ed25519"
"testing"
"github.com/google/go-cmp/cmp"
"tailscale.com/types/key"
)
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)
}
// 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)
}
// 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 i := 0; i < 15; i++ { // 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)
}
}