Fix ParseInsecure to parse the token even when a key is given (#1008)

* Fix ParseInsecure to parse the token even when a key is given

* appease linter

Changes

@@ -42,6 +42,10 @@ v2.0.16 UNRELEASED
   * [jwk] Added `jwk.IsKeyValidationError` that checks if an error is an error
     from `key.Validate()`.
 
+[Bug Fixes]
+  * [jwt] `jwt.ParseInsecure()` was running verification if you provided a key
+    via `jwt.WithKey()` or `jwt.WithKeySet()` (#1007)
+
 v2.0.15 19 20 Oct 2023
 [Bug fixes]
   * [jws] jws.Sign() now properly check for valid algorithm / key type pair when

jwt/jwt.go

@@ -209,6 +209,10 @@ func parseBytes(data []byte, options ...ParseOption) (Token, error) {
 		}
 	}
 
+	if !verification {
+		ctx.skipVerification = true
+	}
+
 	lvo := len(verifyOpts)
 	if lvo == 0 && verification {
 		return nil, fmt.Errorf(`jwt.Parse: no keys for verification are provided (use jwt.WithVerify(false) to explicitly skip)`)

jwt/jwt_test.go

@@ -1743,3 +1743,33 @@ func TestGH951(t *testing.T) {
 
 	require.True(t, jwt.Equal(verified, token), `tokens should be equal`)
 }
+
+func TestGH1007(t *testing.T) {
+	key, err := jwxtest.GenerateRsaJwk()
+	require.NoError(t, err, `jwxtest.GenerateRsaJwk should succeed`)
+
+	tok, err := jwt.NewBuilder().
+		Claim(`claim1`, `value1`).
+		Claim(`claim2`, `value2`).
+		Issuer(`github.com/lestrrat-go/jwx`).
+		Audience([]string{`users`}).
+		Build()
+	require.NoError(t, err, `jwt.NewBuilder should succeed`)
+
+	signed, err := jwt.Sign(tok, jwt.WithKey(jwa.RS256, key))
+	require.NoError(t, err, `jwt.Sign should succeed`)
+
+	// This was the intended usage (no WithKey). This worked from the beginning
+	_, err = jwt.ParseInsecure(signed)
+	require.NoError(t, err, `jwt.ParseInsecure should succeed`)
+
+	// This is the problematic behavior reporded in #1007.
+	// The fact that we're specifying a wrong key caused Parse() to check for
+	// verification and yet fail :/
+	wrongPubKey, err := jwxtest.GenerateRsaPublicJwk()
+	require.NoError(t, err, `jwxtest.GenerateRsaPublicJwk should succeed`)
+	require.NoError(t, err, `jwk.PublicKeyOf should succeed`)
+
+	_, err = jwt.ParseInsecure(signed, jwt.WithKey(jwa.RS256, wrongPubKey))
+	require.NoError(t, err, `jwt.ParseInsecure with jwt.WithKey() should succeed`)
+}