1package jwt 2 3import ( 4 "crypto/subtle" 5 "fmt" 6 "time" 7) 8 9// For a type to be a Claims object, it must just have a Valid method that determines 10// if the token is invalid for any supported reason 11type Claims interface { 12 Valid() error 13} 14 15// Structured version of Claims Section, as referenced at 16// https://tools.ietf.org/html/rfc7519#section-4.1 17// See examples for how to use this with your own claim types 18type StandardClaims struct { 19 Audience string `json:"aud,omitempty"` 20 ExpiresAt int64 `json:"exp,omitempty"` 21 Id string `json:"jti,omitempty"` 22 IssuedAt int64 `json:"iat,omitempty"` 23 Issuer string `json:"iss,omitempty"` 24 NotBefore int64 `json:"nbf,omitempty"` 25 Subject string `json:"sub,omitempty"` 26} 27 28// Validates time based claims "exp, iat, nbf". 29// There is no accounting for clock skew. 30// As well, if any of the above claims are not in the token, it will still 31// be considered a valid claim. 32func (c StandardClaims) Valid() error { 33 vErr := new(ValidationError) 34 now := TimeFunc().Unix() 35 36 // The claims below are optional, by default, so if they are set to the 37 // default value in Go, let's not fail the verification for them. 38 if c.VerifyExpiresAt(now, false) == false { 39 delta := time.Unix(now, 0).Sub(time.Unix(c.ExpiresAt, 0)) 40 vErr.Inner = fmt.Errorf("token is expired by %v", delta) 41 vErr.Errors |= ValidationErrorExpired 42 } 43 44 if c.VerifyIssuedAt(now, false) == false { 45 vErr.Inner = fmt.Errorf("Token used before issued") 46 vErr.Errors |= ValidationErrorIssuedAt 47 } 48 49 if c.VerifyNotBefore(now, false) == false { 50 vErr.Inner = fmt.Errorf("token is not valid yet") 51 vErr.Errors |= ValidationErrorNotValidYet 52 } 53 54 if vErr.valid() { 55 return nil 56 } 57 58 return vErr 59} 60 61// Compares the aud claim against cmp. 62// If required is false, this method will return true if the value matches or is unset 63func (c *StandardClaims) VerifyAudience(cmp string, req bool) bool { 64 return verifyAud(c.Audience, cmp, req) 65} 66 67// Compares the exp claim against cmp. 68// If required is false, this method will return true if the value matches or is unset 69func (c *StandardClaims) VerifyExpiresAt(cmp int64, req bool) bool { 70 return verifyExp(c.ExpiresAt, cmp, req) 71} 72 73// Compares the iat claim against cmp. 74// If required is false, this method will return true if the value matches or is unset 75func (c *StandardClaims) VerifyIssuedAt(cmp int64, req bool) bool { 76 return verifyIat(c.IssuedAt, cmp, req) 77} 78 79// Compares the iss claim against cmp. 80// If required is false, this method will return true if the value matches or is unset 81func (c *StandardClaims) VerifyIssuer(cmp string, req bool) bool { 82 return verifyIss(c.Issuer, cmp, req) 83} 84 85// Compares the nbf claim against cmp. 86// If required is false, this method will return true if the value matches or is unset 87func (c *StandardClaims) VerifyNotBefore(cmp int64, req bool) bool { 88 return verifyNbf(c.NotBefore, cmp, req) 89} 90 91// ----- helpers 92 93func verifyAud(aud string, cmp string, required bool) bool { 94 if aud == "" { 95 return !required 96 } 97 if subtle.ConstantTimeCompare([]byte(aud), []byte(cmp)) != 0 { 98 return true 99 } else { 100 return false 101 } 102} 103 104func verifyExp(exp int64, now int64, required bool) bool { 105 if exp == 0 { 106 return !required 107 } 108 return now <= exp 109} 110 111func verifyIat(iat int64, now int64, required bool) bool { 112 if iat == 0 { 113 return !required 114 } 115 return now >= iat 116} 117 118func verifyIss(iss string, cmp string, required bool) bool { 119 if iss == "" { 120 return !required 121 } 122 if subtle.ConstantTimeCompare([]byte(iss), []byte(cmp)) != 0 { 123 return true 124 } else { 125 return false 126 } 127} 128 129func verifyNbf(nbf int64, now int64, required bool) bool { 130 if nbf == 0 { 131 return !required 132 } 133 return now >= nbf 134} 135