forked from ebhomengo/niki
507 lines
9.1 KiB
Go
507 lines
9.1 KiB
Go
package jwt
|
|
|
|
import (
|
|
"crypto/subtle"
|
|
"fmt"
|
|
"time"
|
|
)
|
|
|
|
// ClaimsValidator is an interface that can be implemented by custom claims who
|
|
|
|
// wish to execute any additional claims validation based on
|
|
|
|
// application-specific logic. The Validate function is then executed in
|
|
|
|
// addition to the regular claims validation and any error returned is appended
|
|
|
|
// to the final validation result.
|
|
|
|
//
|
|
|
|
// type MyCustomClaims struct {
|
|
|
|
// Foo string `json:"foo"`
|
|
|
|
// jwt.RegisteredClaims
|
|
|
|
// }
|
|
|
|
//
|
|
|
|
// func (m MyCustomClaims) Validate() error {
|
|
|
|
// if m.Foo != "bar" {
|
|
|
|
// return errors.New("must be foobar")
|
|
|
|
// }
|
|
|
|
// return nil
|
|
|
|
// }
|
|
|
|
type ClaimsValidator interface {
|
|
Claims
|
|
|
|
Validate() error
|
|
}
|
|
|
|
// validator is the core of the new Validation API. It is automatically used by
|
|
|
|
// a [Parser] during parsing and can be modified with various parser options.
|
|
|
|
//
|
|
|
|
// Note: This struct is intentionally not exported (yet) as we want to
|
|
|
|
// internally finalize its API. In the future, we might make it publicly
|
|
|
|
// available.
|
|
|
|
type validator struct {
|
|
|
|
// leeway is an optional leeway that can be provided to account for clock skew.
|
|
|
|
leeway time.Duration
|
|
|
|
// timeFunc is used to supply the current time that is needed for
|
|
|
|
// validation. If unspecified, this defaults to time.Now.
|
|
|
|
timeFunc func() time.Time
|
|
|
|
// verifyIat specifies whether the iat (Issued At) claim will be verified.
|
|
|
|
// According to https://www.rfc-editor.org/rfc/rfc7519#section-4.1.6 this
|
|
|
|
// only specifies the age of the token, but no validation check is
|
|
|
|
// necessary. However, if wanted, it can be checked if the iat is
|
|
|
|
// unrealistic, i.e., in the future.
|
|
|
|
verifyIat bool
|
|
|
|
// expectedAud contains the audience this token expects. Supplying an empty
|
|
|
|
// string will disable aud checking.
|
|
|
|
expectedAud string
|
|
|
|
// expectedIss contains the issuer this token expects. Supplying an empty
|
|
|
|
// string will disable iss checking.
|
|
|
|
expectedIss string
|
|
|
|
// expectedSub contains the subject this token expects. Supplying an empty
|
|
|
|
// string will disable sub checking.
|
|
|
|
expectedSub string
|
|
}
|
|
|
|
// newValidator can be used to create a stand-alone validator with the supplied
|
|
|
|
// options. This validator can then be used to validate already parsed claims.
|
|
|
|
func newValidator(opts ...ParserOption) *validator {
|
|
|
|
p := NewParser(opts...)
|
|
|
|
return p.validator
|
|
|
|
}
|
|
|
|
// Validate validates the given claims. It will also perform any custom
|
|
|
|
// validation if claims implements the [ClaimsValidator] interface.
|
|
|
|
func (v *validator) Validate(claims Claims) error {
|
|
|
|
var (
|
|
now time.Time
|
|
|
|
errs []error = make([]error, 0, 6)
|
|
|
|
err error
|
|
)
|
|
|
|
// Check, if we have a time func
|
|
|
|
if v.timeFunc != nil {
|
|
|
|
now = v.timeFunc()
|
|
|
|
} else {
|
|
|
|
now = time.Now()
|
|
|
|
}
|
|
|
|
// We always need to check the expiration time, but usage of the claim
|
|
|
|
// itself is OPTIONAL.
|
|
|
|
if err = v.verifyExpiresAt(claims, now, false); err != nil {
|
|
|
|
errs = append(errs, err)
|
|
|
|
}
|
|
|
|
// We always need to check not-before, but usage of the claim itself is
|
|
|
|
// OPTIONAL.
|
|
|
|
if err = v.verifyNotBefore(claims, now, false); err != nil {
|
|
|
|
errs = append(errs, err)
|
|
|
|
}
|
|
|
|
// Check issued-at if the option is enabled
|
|
|
|
if v.verifyIat {
|
|
|
|
if err = v.verifyIssuedAt(claims, now, false); err != nil {
|
|
|
|
errs = append(errs, err)
|
|
|
|
}
|
|
|
|
}
|
|
|
|
// If we have an expected audience, we also require the audience claim
|
|
|
|
if v.expectedAud != "" {
|
|
|
|
if err = v.verifyAudience(claims, v.expectedAud, true); err != nil {
|
|
|
|
errs = append(errs, err)
|
|
|
|
}
|
|
|
|
}
|
|
|
|
// If we have an expected issuer, we also require the issuer claim
|
|
|
|
if v.expectedIss != "" {
|
|
|
|
if err = v.verifyIssuer(claims, v.expectedIss, true); err != nil {
|
|
|
|
errs = append(errs, err)
|
|
|
|
}
|
|
|
|
}
|
|
|
|
// If we have an expected subject, we also require the subject claim
|
|
|
|
if v.expectedSub != "" {
|
|
|
|
if err = v.verifySubject(claims, v.expectedSub, true); err != nil {
|
|
|
|
errs = append(errs, err)
|
|
|
|
}
|
|
|
|
}
|
|
|
|
// Finally, we want to give the claim itself some possibility to do some
|
|
|
|
// additional custom validation based on a custom Validate function.
|
|
|
|
cvt, ok := claims.(ClaimsValidator)
|
|
|
|
if ok {
|
|
|
|
if err := cvt.Validate(); err != nil {
|
|
|
|
errs = append(errs, err)
|
|
|
|
}
|
|
|
|
}
|
|
|
|
if len(errs) == 0 {
|
|
|
|
return nil
|
|
|
|
}
|
|
|
|
return joinErrors(errs...)
|
|
|
|
}
|
|
|
|
// verifyExpiresAt compares the exp claim in claims against cmp. This function
|
|
|
|
// will succeed if cmp < exp. Additional leeway is taken into account.
|
|
|
|
//
|
|
|
|
// If exp is not set, it will succeed if the claim is not required,
|
|
|
|
// otherwise ErrTokenRequiredClaimMissing will be returned.
|
|
|
|
//
|
|
|
|
// Additionally, if any error occurs while retrieving the claim, e.g., when its
|
|
|
|
// the wrong type, an ErrTokenUnverifiable error will be returned.
|
|
|
|
func (v *validator) verifyExpiresAt(claims Claims, cmp time.Time, required bool) error {
|
|
|
|
exp, err := claims.GetExpirationTime()
|
|
|
|
if err != nil {
|
|
|
|
return err
|
|
|
|
}
|
|
|
|
if exp == nil {
|
|
|
|
return errorIfRequired(required, "exp")
|
|
|
|
}
|
|
|
|
return errorIfFalse(cmp.Before((exp.Time).Add(+v.leeway)), ErrTokenExpired)
|
|
|
|
}
|
|
|
|
// verifyIssuedAt compares the iat claim in claims against cmp. This function
|
|
|
|
// will succeed if cmp >= iat. Additional leeway is taken into account.
|
|
|
|
//
|
|
|
|
// If iat is not set, it will succeed if the claim is not required,
|
|
|
|
// otherwise ErrTokenRequiredClaimMissing will be returned.
|
|
|
|
//
|
|
|
|
// Additionally, if any error occurs while retrieving the claim, e.g., when its
|
|
|
|
// the wrong type, an ErrTokenUnverifiable error will be returned.
|
|
|
|
func (v *validator) verifyIssuedAt(claims Claims, cmp time.Time, required bool) error {
|
|
|
|
iat, err := claims.GetIssuedAt()
|
|
|
|
if err != nil {
|
|
|
|
return err
|
|
|
|
}
|
|
|
|
if iat == nil {
|
|
|
|
return errorIfRequired(required, "iat")
|
|
|
|
}
|
|
|
|
return errorIfFalse(!cmp.Before(iat.Add(-v.leeway)), ErrTokenUsedBeforeIssued)
|
|
|
|
}
|
|
|
|
// verifyNotBefore compares the nbf claim in claims against cmp. This function
|
|
|
|
// will return true if cmp >= nbf. Additional leeway is taken into account.
|
|
|
|
//
|
|
|
|
// If nbf is not set, it will succeed if the claim is not required,
|
|
|
|
// otherwise ErrTokenRequiredClaimMissing will be returned.
|
|
|
|
//
|
|
|
|
// Additionally, if any error occurs while retrieving the claim, e.g., when its
|
|
|
|
// the wrong type, an ErrTokenUnverifiable error will be returned.
|
|
|
|
func (v *validator) verifyNotBefore(claims Claims, cmp time.Time, required bool) error {
|
|
|
|
nbf, err := claims.GetNotBefore()
|
|
|
|
if err != nil {
|
|
|
|
return err
|
|
|
|
}
|
|
|
|
if nbf == nil {
|
|
|
|
return errorIfRequired(required, "nbf")
|
|
|
|
}
|
|
|
|
return errorIfFalse(!cmp.Before(nbf.Add(-v.leeway)), ErrTokenNotValidYet)
|
|
|
|
}
|
|
|
|
// verifyAudience compares the aud claim against cmp.
|
|
|
|
//
|
|
|
|
// If aud is not set or an empty list, it will succeed if the claim is not required,
|
|
|
|
// otherwise ErrTokenRequiredClaimMissing will be returned.
|
|
|
|
//
|
|
|
|
// Additionally, if any error occurs while retrieving the claim, e.g., when its
|
|
|
|
// the wrong type, an ErrTokenUnverifiable error will be returned.
|
|
|
|
func (v *validator) verifyAudience(claims Claims, cmp string, required bool) error {
|
|
|
|
aud, err := claims.GetAudience()
|
|
|
|
if err != nil {
|
|
|
|
return err
|
|
|
|
}
|
|
|
|
if len(aud) == 0 {
|
|
|
|
return errorIfRequired(required, "aud")
|
|
|
|
}
|
|
|
|
// use a var here to keep constant time compare when looping over a number of claims
|
|
|
|
result := false
|
|
|
|
var stringClaims string
|
|
|
|
for _, a := range aud {
|
|
|
|
if subtle.ConstantTimeCompare([]byte(a), []byte(cmp)) != 0 {
|
|
|
|
result = true
|
|
|
|
}
|
|
|
|
stringClaims = stringClaims + a
|
|
|
|
}
|
|
|
|
// case where "" is sent in one or many aud claims
|
|
|
|
if stringClaims == "" {
|
|
|
|
return errorIfRequired(required, "aud")
|
|
|
|
}
|
|
|
|
return errorIfFalse(result, ErrTokenInvalidAudience)
|
|
|
|
}
|
|
|
|
// verifyIssuer compares the iss claim in claims against cmp.
|
|
|
|
//
|
|
|
|
// If iss is not set, it will succeed if the claim is not required,
|
|
|
|
// otherwise ErrTokenRequiredClaimMissing will be returned.
|
|
|
|
//
|
|
|
|
// Additionally, if any error occurs while retrieving the claim, e.g., when its
|
|
|
|
// the wrong type, an ErrTokenUnverifiable error will be returned.
|
|
|
|
func (v *validator) verifyIssuer(claims Claims, cmp string, required bool) error {
|
|
|
|
iss, err := claims.GetIssuer()
|
|
|
|
if err != nil {
|
|
|
|
return err
|
|
|
|
}
|
|
|
|
if iss == "" {
|
|
|
|
return errorIfRequired(required, "iss")
|
|
|
|
}
|
|
|
|
return errorIfFalse(iss == cmp, ErrTokenInvalidIssuer)
|
|
|
|
}
|
|
|
|
// verifySubject compares the sub claim against cmp.
|
|
|
|
//
|
|
|
|
// If sub is not set, it will succeed if the claim is not required,
|
|
|
|
// otherwise ErrTokenRequiredClaimMissing will be returned.
|
|
|
|
//
|
|
|
|
// Additionally, if any error occurs while retrieving the claim, e.g., when its
|
|
|
|
// the wrong type, an ErrTokenUnverifiable error will be returned.
|
|
|
|
func (v *validator) verifySubject(claims Claims, cmp string, required bool) error {
|
|
|
|
sub, err := claims.GetSubject()
|
|
|
|
if err != nil {
|
|
|
|
return err
|
|
|
|
}
|
|
|
|
if sub == "" {
|
|
|
|
return errorIfRequired(required, "sub")
|
|
|
|
}
|
|
|
|
return errorIfFalse(sub == cmp, ErrTokenInvalidSubject)
|
|
|
|
}
|
|
|
|
// errorIfFalse returns the error specified in err, if the value is true.
|
|
|
|
// Otherwise, nil is returned.
|
|
|
|
func errorIfFalse(value bool, err error) error {
|
|
|
|
if value {
|
|
|
|
return nil
|
|
|
|
} else {
|
|
|
|
return err
|
|
|
|
}
|
|
|
|
}
|
|
|
|
// errorIfRequired returns an ErrTokenRequiredClaimMissing error if required is
|
|
|
|
// true. Otherwise, nil is returned.
|
|
|
|
func errorIfRequired(required bool, claim string) error {
|
|
|
|
if required {
|
|
|
|
return newError(fmt.Sprintf("%s claim is required", claim), ErrTokenRequiredClaimMissing)
|
|
|
|
} else {
|
|
|
|
return nil
|
|
|
|
}
|
|
|
|
}
|