/usr/share/gocode/src/github.com/dgrijalva/jwt-go/ecdsa.go is in golang-github-dgrijalva-jwt-go-dev 3.0.0.1+REALLY.2.6.0-3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 | package jwt
import (
"crypto"
"crypto/ecdsa"
"crypto/rand"
"errors"
"math/big"
)
var (
// Sadly this is missing from crypto/ecdsa compared to crypto/rsa
ErrECDSAVerification = errors.New("crypto/ecdsa: verification error")
)
// Implements the ECDSA family of signing methods signing methods
type SigningMethodECDSA struct {
Name string
Hash crypto.Hash
KeySize int
CurveBits int
}
// Specific instances for EC256 and company
var (
SigningMethodES256 *SigningMethodECDSA
SigningMethodES384 *SigningMethodECDSA
SigningMethodES512 *SigningMethodECDSA
)
func init() {
// ES256
SigningMethodES256 = &SigningMethodECDSA{"ES256", crypto.SHA256, 32, 256}
RegisterSigningMethod(SigningMethodES256.Alg(), func() SigningMethod {
return SigningMethodES256
})
// ES384
SigningMethodES384 = &SigningMethodECDSA{"ES384", crypto.SHA384, 48, 384}
RegisterSigningMethod(SigningMethodES384.Alg(), func() SigningMethod {
return SigningMethodES384
})
// ES512
SigningMethodES512 = &SigningMethodECDSA{"ES512", crypto.SHA512, 66, 521}
RegisterSigningMethod(SigningMethodES512.Alg(), func() SigningMethod {
return SigningMethodES512
})
}
func (m *SigningMethodECDSA) Alg() string {
return m.Name
}
// Implements the Verify method from SigningMethod
// For this verify method, key must be an ecdsa.PublicKey struct
func (m *SigningMethodECDSA) 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
}
// Get the key
var ecdsaKey *ecdsa.PublicKey
switch k := key.(type) {
case *ecdsa.PublicKey:
ecdsaKey = k
default:
return ErrInvalidKey
}
if len(sig) != 2*m.KeySize {
return ErrECDSAVerification
}
r := big.NewInt(0).SetBytes(sig[:m.KeySize])
s := big.NewInt(0).SetBytes(sig[m.KeySize:])
// Create hasher
if !m.Hash.Available() {
return ErrHashUnavailable
}
hasher := m.Hash.New()
hasher.Write([]byte(signingString))
// Verify the signature
if verifystatus := ecdsa.Verify(ecdsaKey, hasher.Sum(nil), r, s); verifystatus == true {
return nil
} else {
return ErrECDSAVerification
}
}
// Implements the Sign method from SigningMethod
// For this signing method, key must be an ecdsa.PrivateKey struct
func (m *SigningMethodECDSA) Sign(signingString string, key interface{}) (string, error) {
// Get the key
var ecdsaKey *ecdsa.PrivateKey
switch k := key.(type) {
case *ecdsa.PrivateKey:
ecdsaKey = k
default:
return "", ErrInvalidKey
}
// Create the hasher
if !m.Hash.Available() {
return "", ErrHashUnavailable
}
hasher := m.Hash.New()
hasher.Write([]byte(signingString))
// Sign the string and return r, s
if r, s, err := ecdsa.Sign(rand.Reader, ecdsaKey, hasher.Sum(nil)); err == nil {
curveBits := ecdsaKey.Curve.Params().BitSize
if m.CurveBits != curveBits {
return "", ErrInvalidKey
}
keyBytes := curveBits / 8
if curveBits%8 > 0 {
keyBytes += 1
}
// We serialize the outpus (r and s) into big-endian byte arrays and pad
// them with zeros on the left to make sure the sizes work out. Both arrays
// must be keyBytes long, and the output must be 2*keyBytes long.
rBytes := r.Bytes()
rBytesPadded := make([]byte, keyBytes)
copy(rBytesPadded[keyBytes-len(rBytes):], rBytes)
sBytes := s.Bytes()
sBytesPadded := make([]byte, keyBytes)
copy(sBytesPadded[keyBytes-len(sBytes):], sBytes)
out := append(rBytesPadded, sBytesPadded...)
return EncodeSegment(out), nil
} else {
return "", err
}
}
|