File: utils.go

package info (click to toggle)
golang-github-smallstep-crypto 0.63.0-1
  • links: PTS, VCS
  • area: main
  • in suites: experimental
  • size: 3,800 kB
  • sloc: sh: 66; makefile: 50
file content (181 lines) | stat: -rw-r--r-- 4,769 bytes parent folder | download | duplicates (3)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
//go:build !noazurekms
// +build !noazurekms

package azurekms

import (
	"context"
	"crypto"
	"crypto/ecdsa"
	"crypto/elliptic"
	"crypto/rsa"
	"fmt"
	"math/big"
	"net/url"
	"strings"
	"time"

	"github.com/Azure/azure-sdk-for-go/sdk/keyvault/azkeys"
	"github.com/pkg/errors"
	"go.step.sm/crypto/kms/apiv1"
	"go.step.sm/crypto/kms/uri"
)

var now = func() time.Time {
	return time.Now().UTC()
}

// pointer returns the pointer of v.
func pointer[T any](v T) *T {
	return &v
}

// defaultContext returns the default context used in requests to azure.
func defaultContext() (context.Context, context.CancelFunc) {
	return context.WithTimeout(context.Background(), 15*time.Second)
}

// getKeyName returns the uri of the key vault key.
func getKeyName(vault, name string, key *azkeys.JSONWebKey) string {
	if key != nil && key.KID != nil {
		if u, err := url.Parse(string(*key.KID)); err == nil {
			host := strings.SplitN(u.Host, ".", 2)
			path := strings.Split(u.Path, "/")
			if len(host) == 2 && len(path) == 4 {
				values := url.Values{
					"vault": []string{host[0]},
					"name":  []string{path[2]},
				}
				uu := uri.New(Scheme, values)
				uu.RawQuery = url.Values{"version": []string{path[3]}}.Encode()
				return uu.String()
			}
		}
	}

	// Fallback to URI without version id.
	// This will return the latest version of the key.
	values := url.Values{
		"vault": []string{vault},
		"name":  []string{name},
	}
	return uri.New(Scheme, values).String()
}

// parseKeyName returns the key vault, name and version from URIs like:
//
//   - azurekms:vault=key-vault;name=key-name
//   - azurekms:vault=key-vault;name=key-name?version=key-id
//   - azurekms:vault=key-vault;name=key-name?version=key-id&hsm=true
//
// The key-id defines the version of the key, if it is not passed the latest
// version will be used.
//
// HSM can also be passed to define the protection level if this is not given in
// CreateQuery.
func parseKeyName(rawURI string, defaults defaultOptions) (vault, name, version string, hsm bool, err error) {
	var u *uri.URI

	u, err = uri.ParseWithScheme(Scheme, rawURI)
	if err != nil {
		return
	}
	if name = u.Get("name"); name == "" {
		err = errors.Errorf("key uri %q is not valid: name is missing", rawURI)
		return
	}
	if vault = u.Get("vault"); vault == "" {
		if defaults.Vault == "" {
			name = ""
			err = errors.Errorf("key uri %q is not valid: vault is missing", rawURI)
			return
		}
		vault = defaults.Vault
	}
	if u.Get("hsm") == "" {
		hsm = (defaults.ProtectionLevel == apiv1.HSM)
	} else {
		hsm = u.GetBool("hsm")
	}

	version = u.Get("version")

	return
}

func convertKey(key *azkeys.JSONWebKey) (crypto.PublicKey, error) {
	if key == nil || key.Kty == nil {
		return nil, errors.New("invalid key: missing kty value")
	}

	switch *key.Kty {
	case azkeys.JSONWebKeyTypeEC, azkeys.JSONWebKeyTypeECHSM:
		return ecPublicKey(key.Crv, key.X, key.Y)
	case azkeys.JSONWebKeyTypeRSA, azkeys.JSONWebKeyTypeRSAHSM:
		return rsaPublicKey(key.N, key.E)
	case azkeys.JSONWebKeyTypeOct, azkeys.JSONWebKeyTypeOctHSM:
		return octPublicKey(key.K)
	default:
		return nil, fmt.Errorf("invalid key: unsupported kty %q", *key.Kty)
	}
}

func ecPublicKey(crv *azkeys.JSONWebKeyCurveName, x, y []byte) (crypto.PublicKey, error) {
	if crv == nil {
		return nil, errors.New("invalid EC key: missing crv value")
	}
	if len(x) == 0 || len(y) == 0 {
		return nil, errors.New("invalid EC key: missing x or y values")
	}

	var curve elliptic.Curve
	var curveSize int
	switch *crv {
	case azkeys.JSONWebKeyCurveNameP256:
		curve = elliptic.P256()
		curveSize = 32
	case azkeys.JSONWebKeyCurveNameP384:
		curve = elliptic.P384()
		curveSize = 48
	case azkeys.JSONWebKeyCurveNameP521:
		curve = elliptic.P521()
		curveSize = 66 // (521/8 + 1)
	case azkeys.JSONWebKeyCurveNameP256K:
		return nil, fmt.Errorf(`invalid EC key: crv %q is not supported`, *crv)
	default:
		return nil, fmt.Errorf("invalid EC key: crv %q is not supported", *crv)
	}

	if len(x) != curveSize || len(y) != curveSize {
		return nil, errors.New("invalid EC key: x or y length is not valid")
	}

	key := &ecdsa.PublicKey{
		Curve: curve,
		X:     new(big.Int).SetBytes(x),
		Y:     new(big.Int).SetBytes(y),
	}

	if !curve.IsOnCurve(key.X, key.Y) {
		return nil, errors.New("invalid EC key: point (x, y) does not lie on the curve")
	}

	return key, nil
}

func rsaPublicKey(n, e []byte) (crypto.PublicKey, error) {
	if len(n) == 0 || len(e) == 0 {
		return nil, errors.New("invalid RSA key: missing n or e values")
	}
	return &rsa.PublicKey{
		N: new(big.Int).SetBytes(n),
		E: int(new(big.Int).SetBytes(e).Int64()),
	}, nil
}

func octPublicKey(k []byte) (crypto.PublicKey, error) {
	if k == nil {
		return nil, errors.New("invalid oct key: missing k value")
	}
	return k, nil
}