distribution/vendor/github.com/dgrijalva/jwt-go/hmac.go
Sebastiaan van Stijn c5679da3a1
[release/2.7] vendor: github.com/golang-jwt/jwt v3.2.1
to address CVE-2020-26160

full diff: a601269ab7...v3.2.2

3.2.1 release notes
---------------------------------------

- Import Path Change: See MIGRATION_GUIDE.md for tips on updating your code
  Changed the import path from github.com/dgrijalva/jwt-go to github.com/golang-jwt/jwt
- Fixed type confusion issue between string and []string in VerifyAudience.
  This fixes CVE-2020-26160

3.2.2 release notes
---------------------------------------

- Starting from this release, we are adopting the policy to support the most 2
  recent versions of Go currently available. By the time of this release, this
  is Go 1.15 and 1.16.
- Fixed a potential issue that could occur when the verification of exp, iat
  or nbf was not required and contained invalid contents, i.e. non-numeric/date.
  Thanks for @thaJeztah for making us aware of that and @giorgos-f3 for originally
  reporting it to the formtech fork.
- Added support for EdDSA / ED25519.
- Optimized allocations.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
2021-08-10 13:05:39 +02:00

95 lines
2.4 KiB
Go

package jwt
import (
"crypto"
"crypto/hmac"
"errors"
)
// Implements the HMAC-SHA family of signing methods signing methods
// Expects key type of []byte for both signing and validation
type SigningMethodHMAC struct {
Name string
Hash crypto.Hash
}
// Specific instances for HS256 and company
var (
SigningMethodHS256 *SigningMethodHMAC
SigningMethodHS384 *SigningMethodHMAC
SigningMethodHS512 *SigningMethodHMAC
ErrSignatureInvalid = errors.New("signature is invalid")
)
func init() {
// HS256
SigningMethodHS256 = &SigningMethodHMAC{"HS256", crypto.SHA256}
RegisterSigningMethod(SigningMethodHS256.Alg(), func() SigningMethod {
return SigningMethodHS256
})
// HS384
SigningMethodHS384 = &SigningMethodHMAC{"HS384", crypto.SHA384}
RegisterSigningMethod(SigningMethodHS384.Alg(), func() SigningMethod {
return SigningMethodHS384
})
// HS512
SigningMethodHS512 = &SigningMethodHMAC{"HS512", crypto.SHA512}
RegisterSigningMethod(SigningMethodHS512.Alg(), func() SigningMethod {
return SigningMethodHS512
})
}
func (m *SigningMethodHMAC) Alg() string {
return m.Name
}
// Verify the signature of HSXXX tokens. Returns nil if the signature is valid.
func (m *SigningMethodHMAC) Verify(signingString, signature string, key interface{}) error {
// Verify the key is the right type
keyBytes, ok := key.([]byte)
if !ok {
return ErrInvalidKeyType
}
// Decode signature, for comparison
sig, err := DecodeSegment(signature)
if err != nil {
return err
}
// Can we use the specified hashing method?
if !m.Hash.Available() {
return ErrHashUnavailable
}
// This signing method is symmetric, so we validate the signature
// by reproducing the signature from the signing string and key, then
// comparing that against the provided signature.
hasher := hmac.New(m.Hash.New, keyBytes)
hasher.Write([]byte(signingString))
if !hmac.Equal(sig, hasher.Sum(nil)) {
return ErrSignatureInvalid
}
// No validation errors. Signature is good.
return nil
}
// Implements the Sign method from SigningMethod for this signing method.
// Key must be []byte
func (m *SigningMethodHMAC) Sign(signingString string, key interface{}) (string, error) {
if keyBytes, ok := key.([]byte); ok {
if !m.Hash.Available() {
return "", ErrHashUnavailable
}
hasher := hmac.New(m.Hash.New, keyBytes)
hasher.Write([]byte(signingString))
return EncodeSegment(hasher.Sum(nil)), nil
}
return "", ErrInvalidKeyType
}