forked from form3tech-oss/jwt-go
-
Notifications
You must be signed in to change notification settings - Fork 0
/
rsa_pss.go
142 lines (124 loc) · 3.36 KB
/
rsa_pss.go
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
// +build go1.4
package jwt
import (
"crypto"
"crypto/rand"
"crypto/rsa"
)
// Implements the RSAPSS family of signing methods signing methods
type SigningMethodRSAPSS struct {
*SigningMethodRSA
Options *rsa.PSSOptions
// VerifyOptions is optional. If set overrides Options for rsa.VerifyPPS.
// Used to accept tokens signed with rsa.PSSSaltLengthAuto, what doesn't follow
// https://tools.ietf.org/html/rfc7518#section-3.5 but was used previously.
// See https://github.com/dgrijalva/jwt-go/issues/285#issuecomment-437451244 for details.
VerifyOptions *rsa.PSSOptions
}
// Specific instances for RS/PS and company.
var (
SigningMethodPS256 *SigningMethodRSAPSS
SigningMethodPS384 *SigningMethodRSAPSS
SigningMethodPS512 *SigningMethodRSAPSS
)
func init() {
// PS256
SigningMethodPS256 = &SigningMethodRSAPSS{
SigningMethodRSA: &SigningMethodRSA{
Name: "PS256",
Hash: crypto.SHA256,
},
Options: &rsa.PSSOptions{
SaltLength: rsa.PSSSaltLengthEqualsHash,
},
VerifyOptions: &rsa.PSSOptions{
SaltLength: rsa.PSSSaltLengthAuto,
},
}
RegisterSigningMethod(SigningMethodPS256.Alg(), func() SigningMethod {
return SigningMethodPS256
})
// PS384
SigningMethodPS384 = &SigningMethodRSAPSS{
SigningMethodRSA: &SigningMethodRSA{
Name: "PS384",
Hash: crypto.SHA384,
},
Options: &rsa.PSSOptions{
SaltLength: rsa.PSSSaltLengthEqualsHash,
},
VerifyOptions: &rsa.PSSOptions{
SaltLength: rsa.PSSSaltLengthAuto,
},
}
RegisterSigningMethod(SigningMethodPS384.Alg(), func() SigningMethod {
return SigningMethodPS384
})
// PS512
SigningMethodPS512 = &SigningMethodRSAPSS{
SigningMethodRSA: &SigningMethodRSA{
Name: "PS512",
Hash: crypto.SHA512,
},
Options: &rsa.PSSOptions{
SaltLength: rsa.PSSSaltLengthEqualsHash,
},
VerifyOptions: &rsa.PSSOptions{
SaltLength: rsa.PSSSaltLengthAuto,
},
}
RegisterSigningMethod(SigningMethodPS512.Alg(), func() SigningMethod {
return SigningMethodPS512
})
}
// Implements the Verify method from SigningMethod
// For this verify method, key must be an rsa.PublicKey struct
func (m *SigningMethodRSAPSS) Verify(signingString, signature string, key interface{}) error {
var err error
// Decode the signature
var sig []byte
if sig, err = DecodeSegment(signature); err != nil {
return err
}
var rsaKey *rsa.PublicKey
switch k := key.(type) {
case *rsa.PublicKey:
rsaKey = k
default:
return ErrInvalidKey
}
// Create hasher
if !m.Hash.Available() {
return ErrHashUnavailable
}
hasher := m.Hash.New()
hasher.Write([]byte(signingString))
opts := m.Options
if m.VerifyOptions != nil {
opts = m.VerifyOptions
}
return rsa.VerifyPSS(rsaKey, m.Hash, hasher.Sum(nil), sig, opts)
}
// Implements the Sign method from SigningMethod
// For this signing method, key must be an rsa.PrivateKey struct
func (m *SigningMethodRSAPSS) Sign(signingString string, key interface{}) (string, error) {
var rsaKey *rsa.PrivateKey
switch k := key.(type) {
case *rsa.PrivateKey:
rsaKey = k
default:
return "", ErrInvalidKeyType
}
// Create the hasher
if !m.Hash.Available() {
return "", ErrHashUnavailable
}
hasher := m.Hash.New()
hasher.Write([]byte(signingString))
// Sign the string and return the encoded bytes
if sigBytes, err := rsa.SignPSS(rand.Reader, rsaKey, m.Hash, hasher.Sum(nil), m.Options); err == nil {
return EncodeSegment(sigBytes), nil
} else {
return "", err
}
}