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minio/cmd/jwt/parser.go

372 lines
10 KiB

/*
* MinIO Cloud Storage, (C) 2020 MinIO, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package jwt
// This file is a re-implementation of the original code here with some
// additional allocation tweaks reproduced using GODEBUG=allocfreetrace=1
// original file https://github.com/dgrijalva/jwt-go/blob/master/parser.go
// borrowed under MIT License https://github.com/dgrijalva/jwt-go/blob/master/LICENSE
import (
"crypto"
"crypto/hmac"
"encoding/base64"
"encoding/json"
"fmt"
"strings"
"sync"
"time"
jwtgo "github.com/dgrijalva/jwt-go"
jsoniter "github.com/json-iterator/go"
)
// SigningMethodHMAC - 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, HS384, HS512
var (
SigningMethodHS256 *SigningMethodHMAC
SigningMethodHS384 *SigningMethodHMAC
SigningMethodHS512 *SigningMethodHMAC
)
var (
base64BufPool sync.Pool
hmacSigners []*SigningMethodHMAC
)
func init() {
base64BufPool = sync.Pool{
New: func() interface{} {
buf := make([]byte, 8192)
return &buf
},
}
hmacSigners = []*SigningMethodHMAC{
{"HS256", crypto.SHA256},
{"HS384", crypto.SHA384},
{"HS512", crypto.SHA512},
}
}
// StandardClaims are basically standard claims with "accessKey"
type StandardClaims struct {
AccessKey string `json:"accessKey,omitempty"`
jwtgo.StandardClaims
}
// MapClaims - implements custom unmarshaller
type MapClaims struct {
AccessKey string `json:"accessKey,omitempty"`
jwtgo.MapClaims
}
// NewStandardClaims - initializes standard claims
func NewStandardClaims() *StandardClaims {
return &StandardClaims{}
}
// SetIssuer sets issuer for these claims
func (c *StandardClaims) SetIssuer(issuer string) {
c.Issuer = issuer
}
// SetAudience sets audience for these claims
func (c *StandardClaims) SetAudience(aud string) {
c.Audience = aud
}
// SetExpiry sets expiry in unix epoch secs
func (c *StandardClaims) SetExpiry(t time.Time) {
c.ExpiresAt = t.Unix()
}
// SetAccessKey sets access key as jwt subject and custom
// "accessKey" field.
func (c *StandardClaims) SetAccessKey(accessKey string) {
c.Subject = accessKey
c.AccessKey = accessKey
}
// Valid - implements https://godoc.org/github.com/dgrijalva/jwt-go#Claims compatible
// claims interface, additionally validates "accessKey" fields.
func (c *StandardClaims) Valid() error {
if err := c.StandardClaims.Valid(); err != nil {
return err
}
if c.AccessKey == "" && c.Subject == "" {
return jwtgo.NewValidationError("accessKey/sub missing",
jwtgo.ValidationErrorClaimsInvalid)
}
return nil
}
// NewMapClaims - Initializes a new map claims
func NewMapClaims() *MapClaims {
return &MapClaims{MapClaims: jwtgo.MapClaims{}}
}
// Lookup returns the value and if the key is found.
func (c *MapClaims) Lookup(key string) (value string, ok bool) {
var vinterface interface{}
vinterface, ok = c.MapClaims[key]
if ok {
value, ok = vinterface.(string)
}
return
}
// SetExpiry sets expiry in unix epoch secs
func (c *MapClaims) SetExpiry(t time.Time) {
c.MapClaims["exp"] = t.Unix()
}
// SetAccessKey sets access key as jwt subject and custom
// "accessKey" field.
func (c *MapClaims) SetAccessKey(accessKey string) {
c.MapClaims["sub"] = accessKey
c.MapClaims["accessKey"] = accessKey
}
// Valid - implements https://godoc.org/github.com/dgrijalva/jwt-go#Claims compatible
// claims interface, additionally validates "accessKey" fields.
func (c *MapClaims) Valid() error {
if err := c.MapClaims.Valid(); err != nil {
return err
}
if c.AccessKey == "" {
return jwtgo.NewValidationError("accessKey/sub missing",
jwtgo.ValidationErrorClaimsInvalid)
}
return nil
}
// Map returns underlying low-level map claims.
func (c *MapClaims) Map() map[string]interface{} {
return c.MapClaims
}
// MarshalJSON marshals the MapClaims struct
func (c *MapClaims) MarshalJSON() ([]byte, error) {
return json.Marshal(c.MapClaims)
}
// ParseWithStandardClaims - parse the token string, valid methods.
func ParseWithStandardClaims(tokenStr string, claims *StandardClaims, key []byte) error {
// Key is not provided.
if key == nil {
// keyFunc was not provided, return error.
return jwtgo.NewValidationError("no key was provided.", jwtgo.ValidationErrorUnverifiable)
}
bufp := base64BufPool.Get().(*[]byte)
defer base64BufPool.Put(bufp)
signer, err := ParseUnverifiedStandardClaims(tokenStr, claims, *bufp)
if err != nil {
return err
}
i := strings.LastIndex(tokenStr, ".")
if i < 0 {
return jwtgo.ErrSignatureInvalid
}
n, err := base64Decode(tokenStr[i+1:], *bufp)
if err != nil {
return err
}
hasher := hmac.New(signer.Hash.New, key)
hasher.Write([]byte(tokenStr[:i]))
if !hmac.Equal((*bufp)[:n], hasher.Sum(nil)) {
return jwtgo.ErrSignatureInvalid
}
if claims.AccessKey == "" && claims.Subject == "" {
return jwtgo.NewValidationError("accessKey/sub missing",
jwtgo.ValidationErrorClaimsInvalid)
}
// Signature is valid, lets validate the claims for
// other fields such as expiry etc.
return claims.Valid()
}
// https://tools.ietf.org/html/rfc7519#page-11
type jwtHeader struct {
Algorithm string `json:"alg"`
Type string `json:"typ"`
}
// ParseUnverifiedStandardClaims - WARNING: Don't use this method unless you know what you're doing
//
// This method parses the token but doesn't validate the signature. It's only
// ever useful in cases where you know the signature is valid (because it has
// been checked previously in the stack) and you want to extract values from
// it.
func ParseUnverifiedStandardClaims(tokenString string, claims *StandardClaims, buf []byte) (*SigningMethodHMAC, error) {
if strings.Count(tokenString, ".") != 2 {
return nil, jwtgo.ErrSignatureInvalid
}
i := strings.Index(tokenString, ".")
j := strings.LastIndex(tokenString, ".")
n, err := base64Decode(tokenString[:i], buf)
if err != nil {
return nil, &jwtgo.ValidationError{Inner: err, Errors: jwtgo.ValidationErrorMalformed}
}
var header = jwtHeader{}
var json = jsoniter.ConfigCompatibleWithStandardLibrary
if err = json.Unmarshal(buf[:n], &header); err != nil {
return nil, &jwtgo.ValidationError{Inner: err, Errors: jwtgo.ValidationErrorMalformed}
}
n, err = base64Decode(tokenString[i+1:j], buf)
if err != nil {
return nil, &jwtgo.ValidationError{Inner: err, Errors: jwtgo.ValidationErrorMalformed}
}
if err = json.Unmarshal(buf[:n], claims); err != nil {
return nil, &jwtgo.ValidationError{Inner: err, Errors: jwtgo.ValidationErrorMalformed}
}
for _, signer := range hmacSigners {
if header.Algorithm == signer.Name {
return signer, nil
}
}
return nil, jwtgo.NewValidationError(fmt.Sprintf("signing method (%s) is unavailable.", header.Algorithm),
jwtgo.ValidationErrorUnverifiable)
}
// ParseWithClaims - parse the token string, valid methods.
func ParseWithClaims(tokenStr string, claims *MapClaims, fn func(*MapClaims) ([]byte, error)) error {
// Key lookup function has to be provided.
if fn == nil {
// keyFunc was not provided, return error.
return jwtgo.NewValidationError("no Keyfunc was provided.", jwtgo.ValidationErrorUnverifiable)
}
bufp := base64BufPool.Get().(*[]byte)
defer base64BufPool.Put(bufp)
signer, err := ParseUnverifiedMapClaims(tokenStr, claims, *bufp)
if err != nil {
return err
}
i := strings.LastIndex(tokenStr, ".")
if i < 0 {
return jwtgo.ErrSignatureInvalid
}
n, err := base64Decode(tokenStr[i+1:], *bufp)
if err != nil {
return err
}
var ok bool
claims.AccessKey, ok = claims.Lookup("accessKey")
if !ok {
claims.AccessKey, ok = claims.Lookup("sub")
if !ok {
return jwtgo.NewValidationError("accessKey/sub missing",
jwtgo.ValidationErrorClaimsInvalid)
}
}
// Lookup key from claims, claims may not be valid and may return
// invalid key which is okay as the signature verification will fail.
key, err := fn(claims)
if err != nil {
return err
}
hasher := hmac.New(signer.Hash.New, key)
hasher.Write([]byte(tokenStr[:i]))
if !hmac.Equal((*bufp)[:n], hasher.Sum(nil)) {
return jwtgo.ErrSignatureInvalid
}
// Signature is valid, lets validate the claims for
// other fields such as expiry etc.
return claims.Valid()
}
// base64Decode returns the bytes represented by the base64 string s.
func base64Decode(s string, buf []byte) (int, error) {
return base64.RawURLEncoding.Decode(buf, []byte(s))
}
// ParseUnverifiedMapClaims - WARNING: Don't use this method unless you know what you're doing
//
// This method parses the token but doesn't validate the signature. It's only
// ever useful in cases where you know the signature is valid (because it has
// been checked previously in the stack) and you want to extract values from
// it.
func ParseUnverifiedMapClaims(tokenString string, claims *MapClaims, buf []byte) (*SigningMethodHMAC, error) {
if strings.Count(tokenString, ".") != 2 {
return nil, jwtgo.ErrSignatureInvalid
}
i := strings.Index(tokenString, ".")
j := strings.LastIndex(tokenString, ".")
n, err := base64Decode(tokenString[:i], buf)
if err != nil {
return nil, &jwtgo.ValidationError{Inner: err, Errors: jwtgo.ValidationErrorMalformed}
}
var header = jwtHeader{}
var json = jsoniter.ConfigCompatibleWithStandardLibrary
if err = json.Unmarshal(buf[:n], &header); err != nil {
return nil, &jwtgo.ValidationError{Inner: err, Errors: jwtgo.ValidationErrorMalformed}
}
n, err = base64Decode(tokenString[i+1:j], buf)
if err != nil {
return nil, &jwtgo.ValidationError{Inner: err, Errors: jwtgo.ValidationErrorMalformed}
}
if err = json.Unmarshal(buf[:n], &claims.MapClaims); err != nil {
return nil, &jwtgo.ValidationError{Inner: err, Errors: jwtgo.ValidationErrorMalformed}
}
for _, signer := range hmacSigners {
if header.Algorithm == signer.Name {
return signer, nil
}
}
return nil, jwtgo.NewValidationError(fmt.Sprintf("signing method (%s) is unavailable.", header.Algorithm),
jwtgo.ValidationErrorUnverifiable)
}