Monorepo for Tangled
tangled.org
crypto: add tests for VerifySignature and SSHFingerprint
Signed-off-by: Matías Insaurralde <matias@insaurral.de>
author
Matías Insaurralde
committer
Tangled
date
(May 5, 2026, 5:25 PM +0300)
commit
0c4cb06d
0c4cb06dc4771ec38c388bd0ea0b025aad3fbfb2
parent
6cb52877
6cb52877f9b86dfaedbaed6fc8d346b0101e82e5
+134
+134
crypto/verify_test.go
+134
crypto/verify_test.go
···
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package crypto
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import (
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"bytes"
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"crypto/ed25519"
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"crypto/rand"
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"strings"
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"testing"
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"github.com/hiddeco/sshsig"
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"golang.org/x/crypto/ssh"
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)
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// testKey generates an ephemeral ed25519 key pair and returns the ssh.Signer
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// and the public key in authorized_keys format.
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func testKey(t *testing.T) (ssh.Signer, []byte) {
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t.Helper()
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_, priv, err := ed25519.GenerateKey(rand.Reader)
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if err != nil {
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t.Fatalf("generate ed25519 key: %v", err)
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}
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signer, err := ssh.NewSignerFromKey(priv)
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if err != nil {
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t.Fatalf("create signer: %v", err)
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}
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return signer, ssh.MarshalAuthorizedKey(signer.PublicKey())
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}
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// testSign signs payload with signer using the same parameters as VerifySignature
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// expects (SHA-512, "git" namespace) and returns the armored signature.
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func testSign(t *testing.T, signer ssh.Signer, payload []byte) []byte {
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t.Helper()
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sig, err := sshsig.Sign(bytes.NewReader(payload), signer, sshsig.HashSHA512, "git")
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if err != nil {
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t.Fatalf("sign payload: %v", err)
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}
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return sshsig.Armor(sig)
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}
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func TestSSHFingerprint(t *testing.T) {
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t.Run("valid key returns SHA256 fingerprint", func(t *testing.T) {
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_, pubKeyBytes := testKey(t)
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fp, err := SSHFingerprint(string(pubKeyBytes))
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if err != nil {
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t.Fatalf("unexpected error: %v", err)
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}
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if !strings.HasPrefix(fp, "SHA256:") {
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t.Errorf("fingerprint %q does not start with SHA256:", fp)
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}
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})
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t.Run("same key returns identical fingerprint", func(t *testing.T) {
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_, pubKeyBytes := testKey(t)
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fp1, _ := SSHFingerprint(string(pubKeyBytes))
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fp2, _ := SSHFingerprint(string(pubKeyBytes))
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if fp1 != fp2 {
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t.Errorf("fingerprint not deterministic: %q != %q", fp1, fp2)
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}
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})
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t.Run("different keys return different fingerprints", func(t *testing.T) {
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_, pub1 := testKey(t)
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_, pub2 := testKey(t)
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fp1, _ := SSHFingerprint(string(pub1))
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fp2, _ := SSHFingerprint(string(pub2))
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if fp1 == fp2 {
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t.Error("different keys produced the same fingerprint")
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}
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})
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t.Run("malformed key returns error", func(t *testing.T) {
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_, err := SSHFingerprint("not a valid ssh public key")
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if err == nil {
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t.Error("expected error for malformed key")
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}
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})
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}
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func TestVerifySignature(t *testing.T) {
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signer, pubKeyBytes := testKey(t)
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payload := []byte("test payload")
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armoredSig := testSign(t, signer, payload)
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t.Run("valid signature verifies successfully", func(t *testing.T) {
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err, ok := VerifySignature(pubKeyBytes, armoredSig, payload)
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if err != nil {
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t.Errorf("unexpected error: %v", err)
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}
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if !ok {
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t.Error("expected ok=true for valid signature")
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}
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})
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t.Run("malformed public key returns error", func(t *testing.T) {
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err, ok := VerifySignature([]byte("not a valid key"), armoredSig, payload)
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if err == nil {
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t.Error("expected error for malformed public key")
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}
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if ok {
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t.Error("expected ok=false")
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}
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})
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t.Run("malformed signature returns error", func(t *testing.T) {
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err, ok := VerifySignature(pubKeyBytes, []byte("not a valid signature"), payload)
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if err == nil {
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t.Error("expected error for malformed signature")
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}
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if ok {
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t.Error("expected ok=false")
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}
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})
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t.Run("tampered payload fails verification", func(t *testing.T) {
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err, ok := VerifySignature(pubKeyBytes, armoredSig, []byte("tampered"))
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if err == nil {
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t.Error("expected error for tampered payload")
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}
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if ok {
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t.Error("expected ok=false for tampered payload")
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}
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})
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t.Run("wrong public key fails verification", func(t *testing.T) {
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_, otherPubKey := testKey(t)
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err, ok := VerifySignature(otherPubKey, armoredSig, payload)
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if err == nil {
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t.Error("expected error for wrong public key")
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}
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if ok {
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t.Error("expected ok=false for wrong public key")
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}
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})
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}