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
|
package jwt
import (
"bytes"
"encoding/json"
"fmt"
"strings"
)
type Parser struct {
ValidMethods []string // If populated, only these methods will be considered valid
UseJSONNumber bool // Use JSON Number format in JSON decoder
SkipClaimsValidation bool // Skip claims validation during token parsing
}
// Parse, validate, and return a token.
// keyFunc will receive the parsed token and should return the key for validating.
// If everything is kosher, err will be nil
func (p *Parser) Parse(tokenString string, keyFunc Keyfunc) (*Token, error) {
return p.ParseWithClaims(tokenString, MapClaims{}, keyFunc)
}
func (p *Parser) ParseWithClaims(tokenString string, claims Claims, keyFunc Keyfunc) (*Token, error) {
parts := strings.Split(tokenString, ".")
if len(parts) != 3 {
return nil, NewValidationError("token contains an invalid number of segments", ValidationErrorMalformed)
}
var err error
token := &Token{Raw: tokenString}
// parse Header
var headerBytes []byte
if headerBytes, err = DecodeSegment(parts[0]); err != nil {
if strings.HasPrefix(strings.ToLower(tokenString), "bearer ") {
return token, NewValidationError("tokenstring should not contain 'bearer '", ValidationErrorMalformed)
}
return token, &ValidationError{Inner: err, Errors: ValidationErrorMalformed}
}
if err = json.Unmarshal(headerBytes, &token.Header); err != nil {
return token, &ValidationError{Inner: err, Errors: ValidationErrorMalformed}
}
// parse Claims
var claimBytes []byte
token.Claims = claims
if claimBytes, err = DecodeSegment(parts[1]); err != nil {
return token, &ValidationError{Inner: err, Errors: ValidationErrorMalformed}
}
dec := json.NewDecoder(bytes.NewBuffer(claimBytes))
if p.UseJSONNumber {
dec.UseNumber()
}
// JSON Decode. Special case for map type to avoid weird pointer behavior
if c, ok := token.Claims.(MapClaims); ok {
err = dec.Decode(&c)
} else {
err = dec.Decode(&claims)
}
// Handle decode error
if err != nil {
return token, &ValidationError{Inner: err, Errors: ValidationErrorMalformed}
}
// Lookup signature method
if method, ok := token.Header["alg"].(string); ok {
if token.Method = GetSigningMethod(method); token.Method == nil {
return token, NewValidationError("signing method (alg) is unavailable.", ValidationErrorUnverifiable)
}
} else {
return token, NewValidationError("signing method (alg) is unspecified.", ValidationErrorUnverifiable)
}
// Verify signing method is in the required set
if p.ValidMethods != nil {
var signingMethodValid = false
var alg = token.Method.Alg()
for _, m := range p.ValidMethods {
if m == alg {
signingMethodValid = true
break
}
}
if !signingMethodValid {
// signing method is not in the listed set
return token, NewValidationError(fmt.Sprintf("signing method %v is invalid", alg), ValidationErrorSignatureInvalid)
}
}
// Lookup key
var key interface{}
if keyFunc == nil {
// keyFunc was not provided. short circuiting validation
return token, NewValidationError("no Keyfunc was provided.", ValidationErrorUnverifiable)
}
if key, err = keyFunc(token); err != nil {
// keyFunc returned an error
return token, &ValidationError{Inner: err, Errors: ValidationErrorUnverifiable}
}
vErr := &ValidationError{}
// Validate Claims
if !p.SkipClaimsValidation {
if err := token.Claims.Valid(); err != nil {
// If the Claims Valid returned an error, check if it is a validation error,
// If it was another error type, create a ValidationError with a generic ClaimsInvalid flag set
if e, ok := err.(*ValidationError); !ok {
vErr = &ValidationError{Inner: err, Errors: ValidationErrorClaimsInvalid}
} else {
vErr = e
}
}
}
// Perform validation
token.Signature = parts[2]
if err = token.Method.Verify(strings.Join(parts[0:2], "."), token.Signature, key); err != nil {
vErr.Inner = err
vErr.Errors |= ValidationErrorSignatureInvalid
}
if vErr.valid() {
token.Valid = true
return token, nil
}
return token, vErr
}
|
