wip

.github/workflows/build.yaml

@@ -1,4 +1,4 @@
-# SPDX-FileCopyrightText: 2023 Steffen Vogel <post@steffenvogel.de>
+# SPDX-FileCopyrightText: 2024 Steffen Vogel <post@steffenvogel.de>
 # SPDX-License-Identifier: Apache-2.0
 
 # yaml-language-server: $schema=https://raw.githubusercontent.com/SchemaStore/schemastore/master/src/schemas/json/github-workflow.json
@@ -14,9 +14,9 @@ on:
 jobs:
   build:
     name: Build
-    
+
     runs-on: ${{ matrix.os }}
-    
+
     strategy:
       fail-fast: false
       matrix:

.golangci.yaml

@@ -1,4 +1,4 @@
-# SPDX-FileCopyrightText: 2023 Steffen Vogel <post@steffenvogel.de>
+# SPDX-FileCopyrightText: 2024 Steffen Vogel <post@steffenvogel.de>
 # SPDX-License-Identifier: Apache-2.0
 
 linters-settings:
@@ -27,7 +27,7 @@ linters-settings:
     sections:
     - standard
     - default
-    - prefix(cunicu.li/skeleton)
+    - prefix(cunicu.li/go-trussed-secrets)
     - blank
     - dot
 

.reuse/dep5

@@ -1,7 +1,7 @@
 Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
-Upstream-Name: skeleton
+Upstream-Name: go-trussed-secrets
 Upstream-Contact: Steffen Vogel <post@steffenvogel.de>
-Source: https://github.com/stv0g/skeleton
+Source: https://github.com/stv0g/go-trussed-secrets
 
 Files: go.sum .renovaterc.json flake.lock
 Copyright: 2023 Steffen Vogel <post@steffenvogel.de>

CODEOWNERS

@@ -1,4 +1,4 @@
-# SPDX-FileCopyrightText: 2023 Steffen Vogel <post@steffenvogel.de>
+# SPDX-FileCopyrightText: 2024 Steffen Vogel <post@steffenvogel.de>
 # SPDX-License-Identifier: Apache-2.0
 
 * @stv0g

README.md

@@ -1,27 +1,70 @@
 <!--
-SPDX-FileCopyrightText: 2023 Steffen Vogel <post@steffenvogel.de>
+SPDX-FileCopyrightText: 2024 Steffen Vogel <post@steffenvogel.de>
 SPDX-License-Identifier: Apache-2.0
 -->
 
-# skeleton: Template repository for Go packages in the cunicu organization
+# go-trussed-secrets
 
-[![GitHub Workflow Status](https://img.shields.io/github/actions/workflow/status/cunicu/skeleton/test.yaml?style=flat-square)](https://github.com/cunicu/skeleton/actions)
-[![goreportcard](https://goreportcard.com/badge/github.com/cunicu/skeleton?style=flat-square)](https://goreportcard.com/report/github.com/cunicu/skeleton)
-[![Codecov branch](https://img.shields.io/codecov/c/github/cunicu/skeleton/main?style=flat-square&token=6XoWouQg6K)](https://app.codecov.io/gh/cunicu/skeleton/tree/main)
-[![License](https://img.shields.io/badge/license-Apache%202.0-blue?style=flat-square)](https://github.com/cunicu/skeleton/blob/main/LICENSES/Apache-2.0.txt)
-![GitHub go.mod Go version](https://img.shields.io/github/go-mod/go-version/cunicu/skeleton?style=flat-square)
-[![Go Reference](https://pkg.go.dev/badge/github.com/cunicu/skeleton.svg)](https://pkg.go.dev/github.com/cunicu/skeleton)
+[![GitHub Workflow Status](https://img.shields.io/github/actions/workflow/status/cunicu/go-trussed-secrets/test.yaml?style=flat-square)](https://github.com/cunicu/go-trussed-secrets/actions)
+[![goreportcard](https://goreportcard.com/badge/github.com/cunicu/go-trussed-secrets?style=flat-square)](https://goreportcard.com/report/github.com/cunicu/go-trussed-secrets)
+[![Codecov branch](https://img.shields.io/codecov/c/github/cunicu/go-trussed-secrets/main?style=flat-square&token=6XoWouQg6K)](https://app.codecov.io/gh/cunicu/go-trussed-secrets/tree/main)
+[![License](https://img.shields.io/badge/license-Apache%202.0-blue?style=flat-square)](https://github.com/cunicu/go-trussed-secrets/blob/main/LICENSES/Apache-2.0.txt)
+![GitHub go.mod Go version](https://img.shields.io/github/go-mod/go-version/cunicu/go-trussed-secrets?style=flat-square)
+[![Go Reference](https://pkg.go.dev/badge/github.com/cunicu/go-trussed-secrets.svg)](https://pkg.go.dev/github.com/cunicu/go-trussed-secrets)
 
-This `skeleton` repo a template for new Go packages belonging to the cunicu organization.
+The package `go-trussed-secrets` implements the protocol of the [_Trussed Secrets App_](https://github.com/Nitrokey/trussed-secrets-app).
+It is used by the Nitrokey 3 tokens to provide HOTP, TOTP, reverse HOTP and challenge/response credentials.
 
-## Install
+**Note:** This package uses the CCID smart-card interface rather than the [CTAPHID](https://github.com/Nitrokey/trussed-secrets-app/blob/main/docs/ctaphid.md) interface as used by [pynitrokey](https://github.com/Nitrokey/pynitrokey)
 
-## Usage
+## Features
+
+- Calculation of
+  - Time-based One-time Passwords (TOTP)
+  - Hash-based One-time Passwords (HOTP)
+  - Reverse Hash-based One-time Passwords (HOTP)
+  - Static password safe entries
+- PIN based authentication
+- Factory reset of applet
+- Credential management
+  - Add
+  - Get
+  - List
+  - Remove
+  - Update
+  - Rename
+
+### Unimplemented
+
+The following features have not been implemented as they have been deprecated in [Nitrokey/trussed-secrets-app](https://github.com/Nitrokey/trussed-secrets-app):
+
+- [YubiKey challenge/response slots](https://docs.yubico.com/yesdk/users-manual/application-otp/challenge-response.html) (as used by KeePassXC)
+  - Also includes challenge/response-based PIN authentication
+- `CalculateAll` instruction
+  - Is disabled by default on Nitrokey 3's
+
+## Roadmap
+
+- [Untruncated responses](https://github.com/Nitrokey/trussed-secrets-app/issues/116)
+- [CTAPHID interface](https://github.com/Nitrokey/trussed-secrets-app/blob/main/docs/ctaphid.md)
+
+## Tested devices
+
+- Nitrokey 3
+  - FW version v1.7.0
+
+## References
+
+- [**RFC 4226:** HOTP: An HMAC-Based One-Time Password Algorithm](https://datatracker.ietf.org/doc/html/rfc4226)
+- [**RFC 6238:** TOTP: Time-Based One-Time Password Algorithm](https://datatracker.ietf.org/doc/html/rfc6238)
+- [CTAPHID Protocol specification](https://github.com/Nitrokey/trussed-secrets-app/blob/main/docs/ctaphid.md)
+- Token App: [Nitrokey/trussed-secrets-app](https://github.com/Nitrokey/trussed-secrets-app)
+- Client CLI: [Nitrokey/pynitrokey (`pynitrokey/nk3/secrets_app.py`)](https://github.com/Nitrokey/pynitrokey/blob/master/pynitrokey/nk3/secrets_app.py)
 
 ## Authors
 
 - Steffen Vogel ([@stv0g](https://github.com/stv0g))
 
 ## License
 
-skeleton is licensed under the [Apache 2.0](./LICENSE) license.
+go-trussed-secrets is licensed under the [Apache 2.0](./LICENSE) license.

algorithm.go

@@ -0,0 +1,62 @@
+// SPDX-FileCopyrightText: 2024 Steffen Vogel <post@steffenvogel.de>
+// SPDX-License-Identifier: Apache-2.0
+
+package secrets
+
+import (
+	"crypto/sha1" //nolint:gosec
+	"crypto/sha256"
+	"crypto/sha512"
+	"fmt"
+	"hash"
+)
+
+// Algorithm denotes the HMAC algorithm used for deriving the one-time passwords
+type Algorithm byte
+
+const (
+	// HMACSHA1 describes a HMAC with SHA-1.
+	HMACSHA1 Algorithm = 0x01
+
+	// HMACSHA256 describes a HMAC with SHA-2 (256-bit).
+	HMACSHA256 Algorithm = 0x02
+
+	// HMACSHA512 describes a HMAC with SHA-2 (512-bit).
+	// TODO: Not yet supported by firmware.
+	HMACSHA512 Algorithm = 0x03
+)
+
+// String returns a string representation of the algorithm.
+func (a Algorithm) String() string {
+	switch a {
+	case HMACSHA1:
+		return "HMAC-SHA1"
+
+	case HMACSHA256:
+		return "HMAC-SHA256"
+
+	case HMACSHA512:
+		return "HMAC-SHA512"
+
+	default:
+		return fmt.Sprintf("unknown %x", byte(a))
+	}
+}
+
+// Hash returns a constructor to create a new hash.Hash object
+// for the given algorithm.
+func (a Algorithm) Hash() func() hash.Hash {
+	switch a {
+	case HMACSHA1:
+		return sha1.New
+
+	case HMACSHA256:
+		return sha256.New
+
+	case HMACSHA512:
+		return sha512.New
+
+	default:
+		return nil
+	}
+}

calculate.go

@@ -0,0 +1,56 @@
+// SPDX-FileCopyrightText: 2024 Steffen Vogel <post@steffenvogel.de>
+// SPDX-License-Identifier: Apache-2.0
+
+package secrets
+
+import (
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"time"
+
+	"cunicu.li/go-iso7816/encoding/tlv"
+)
+
+var ErrNoValuesFound = errors.New("no values found in response")
+
+// Calculate calculates a TOTP, HOTP with using the clock or current counter value.
+func (c *Card) Calculate(id string) (Code, error) {
+	return c.CalculateWithChallenge(id, ChallengeTOTP(c.Clock(), c.Timestep))
+}
+
+// Calculate a TOTP or HMAC by providing a challenge.
+func (c *Card) CalculateWithChallenge(id string, challenge []byte) (Code, error) {
+	// Unlike in YKOATH, the Trussed secrets app only returns truncated
+	// codes for HOTP and TOTP credentials.
+	tvs, err := c.send(insCalculate, 0x00, 0x01,
+		tlv.New(tagCredentialID, []byte(id)),
+		tlv.New(tagChallenge, challenge),
+	)
+	if err != nil {
+		return Code{}, err
+	}
+
+	for _, tv := range tvs {
+		switch tv.Tag {
+		case tagResponse, tagTruncated:
+			digits := int(tv.Value[0])
+			hash := tv.Value[1:]
+			return Code{
+				Digest:    hash,
+				Digits:    digits,
+				Truncated: tv.Tag == tagTruncated,
+			}, nil
+
+		default:
+			return Code{}, fmt.Errorf("%w: %x", errUnknownTag, tv.Tag)
+		}
+	}
+
+	return Code{}, ErrNoValuesFound
+}
+
+func ChallengeTOTP(t time.Time, ts time.Duration) []byte {
+	counter := t.Unix() / int64(ts.Seconds())
+	return binary.BigEndian.AppendUint64(nil, uint64(counter))
+}

calculate_test.go

@@ -0,0 +1,127 @@
+// SPDX-FileCopyrightText: 2024 Steffen Vogel <post@steffenvogel.de>
+// SPDX-License-Identifier: Apache-2.0
+
+package secrets_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	secrets "cunicu.li/go-trussed-secrets"
+)
+
+func TestCalculate(t *testing.T) {
+	vs := vectorsTOTP
+	vs = append(vs, vectorsHOTP...)
+
+	withCard(t, vs, true, func(t *testing.T, card *secrets.Card) {
+		require := require.New(t)
+
+		for _, v := range vs {
+			chal := secrets.ChallengeTOTP(v.Time, secrets.DefaultTimeStep)
+			code, err := card.CalculateWithChallenge(v.ID, chal)
+			require.NoError(err)
+			require.Equal(v.Code, code.OTP())
+		}
+	})
+}
+
+// func TestCalculateRequireTouch(t *testing.T) {
+// 	withCard(t, []vector{
+// 		{
+// 			ID:         "touch-required",
+// 			Algorithm:  secrets.HMACSHA256,
+// 			Kind:       secrets.TOTP,
+// 			Digits:     6,
+// 			Secret:     fromHex("12341234"),
+// 			Properties: secrets.TouchRequired,
+// 		},
+// 	}, true, func(t *testing.T, card *secrets.Card) {
+// 		require := require.New(t)
+
+// 		// Callback missing
+// 		_, err := card.Calculate("touch-required")
+// 		require.ErrorIs(err, secrets.ErrTouchCallbackRequired)
+
+// 		// Error raised in callback
+// 		_, err = card.Calculate("touch-required", func(s string) error {
+// 			return errors.New("my error") //nolint:goerr113
+// 		})
+// 		require.ErrorContains(err, "my error")
+
+// 		// Callback called but button not pressed
+// 		touchRequested := false
+// 		_, err = card.Calculate("touch-required", func(s string) error {
+// 			require.Equal(s, "touch-required")
+// 			touchRequested = true
+// 			return nil
+// 		})
+// 		require.NoError(err)
+// 		require.True(touchRequested)
+// 	})
+// }
+
+func TestCalculateTOTP(t *testing.T) {
+	v := vectorsTOTP[0]
+	withCard(t, []vector{v}, true, func(t *testing.T, card *secrets.Card) {
+		require := require.New(t)
+
+		code, err := card.Calculate(v.ID)
+		require.NoError(err)
+		require.Equal(v.Code, code)
+	})
+}
+
+func TestCalculateHOTPCounterIncrement(t *testing.T) {
+	v := vectorsHOTP[0]
+	withCard(t, []vector{v}, true, func(t *testing.T, card *secrets.Card) {
+		require := require.New(t)
+
+		for _, ev := range vectorsHOTP[:10] {
+			code, err := card.Calculate(v.ID)
+			require.NoError(err)
+			require.Equal(ev.Code, code.OTP())
+			require.Equal(v.Digits, code.Digits)
+			require.True(code.Truncated)
+		}
+	})
+}
+
+func TestCalculateHOTPCounterInit(t *testing.T) {
+	withCard(t, vectorsHOTP, true, func(t *testing.T, card *secrets.Card) {
+		require := require.New(t)
+
+		for _, v := range vectorsHOTP {
+			code, err := card.Calculate(v.ID)
+			require.NoError(err)
+			require.Equal(v.Code, code.OTP())
+			require.Equal(v.Digits, code.Digits)
+			require.True(code.Truncated)
+		}
+	})
+}
+
+// func TestCalculateHMAC(t *testing.T) {
+// 	expResp := fromHex("28c6d33a03e7c67940c30d06253f8980f8ef54bd")
+
+// 	v := vector{
+// 		ID:        "hmac-test-01",
+// 		Algorithm: secrets.HMACSHA1,
+// 		Kind:      secrets.HMAC,
+// 		Secret:    testSecretSHA1,
+// 	}
+
+// 	withCard(t, []vector{v}, true, func(t *testing.T, card *secrets.Card) {
+// 		require := require.New(t)
+
+// 		code, err := card.CalculateWithChallenge(v.ID, fromString("hallo"))
+// 		require.NoError(err)
+// 		require.Equal(expResp, code.Hash)
+// 		require.False(code.Truncated)
+// 		require.Zero(code.Digits)
+
+// 		hash := v.Algorithm.Hash()()
+// 		require.Len(code.Hash, hash.Size())
+// 	})
+// }