/usr/share/gocode/src/github.com/dgrijalva/jwt-go/parser.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 | 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
}
// 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) {
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
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()
}
if err = dec.Decode(&token.Claims); 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}
}
// Check expiration times
vErr := &ValidationError{}
now := TimeFunc().Unix()
var exp, nbf int64
var vexp, vnbf bool
// Parse 'exp' claim
switch num := token.Claims["exp"].(type) {
case json.Number:
if exp, err = num.Int64(); err == nil {
vexp = true
}
case float64:
vexp = true
exp = int64(num)
}
// Parse 'nbf' claim
switch num := token.Claims["nbf"].(type) {
case json.Number:
if nbf, err = num.Int64(); err == nil {
vnbf = true
}
case float64:
vnbf = true
nbf = int64(num)
}
if vexp && now > exp {
vErr.Inner = fmt.Errorf("token is expired")
vErr.Errors |= ValidationErrorExpired
}
if vnbf && now < nbf {
vErr.Inner = fmt.Errorf("token is not valid yet")
vErr.Errors |= ValidationErrorNotValidYet
}
// 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
}
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