minio/pkg/auth/credentials.go

131 lines
3.9 KiB
Go

/*
* Minio Cloud Storage, (C) 2015, 2016, 2017 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 auth
import (
"crypto/rand"
"crypto/subtle"
"encoding/base64"
"fmt"
)
const (
// Minimum length for Minio access key.
accessKeyMinLen = 3
// Maximum length for Minio access key.
// There is no max length enforcement for access keys
accessKeyMaxLen = 20
// Minimum length for Minio secret key for both server and gateway mode.
secretKeyMinLen = 8
// Maximum secret key length for Minio, this
// is used when autogenerating new credentials.
// There is no max length enforcement for secret keys
secretKeyMaxLen = 40
// Alpha numeric table used for generating access keys.
alphaNumericTable = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"
// Total length of the alpha numeric table.
alphaNumericTableLen = byte(len(alphaNumericTable))
)
// Common errors generated for access and secret key validation.
var (
ErrInvalidAccessKeyLength = fmt.Errorf("access key must be minimum %v or more characters long", accessKeyMinLen)
ErrInvalidSecretKeyLength = fmt.Errorf("secret key must be minimum %v or more characters long", secretKeyMinLen)
)
// IsAccessKeyValid - validate access key for right length.
func IsAccessKeyValid(accessKey string) bool {
return len(accessKey) >= accessKeyMinLen
}
// isSecretKeyValid - validate secret key for right length.
func isSecretKeyValid(secretKey string) bool {
return len(secretKey) >= secretKeyMinLen
}
// Credentials holds access and secret keys.
type Credentials struct {
AccessKey string `json:"accessKey,omitempty"`
SecretKey string `json:"secretKey,omitempty"`
}
// IsValid - returns whether credential is valid or not.
func (cred Credentials) IsValid() bool {
return IsAccessKeyValid(cred.AccessKey) && isSecretKeyValid(cred.SecretKey)
}
// Equal - returns whether two credentials are equal or not.
func (cred Credentials) Equal(ccred Credentials) bool {
if !ccred.IsValid() {
return false
}
return cred.AccessKey == ccred.AccessKey && subtle.ConstantTimeCompare([]byte(cred.SecretKey), []byte(ccred.SecretKey)) == 1
}
// GetNewCredentials generates and returns new credential.
func GetNewCredentials() (cred Credentials, err error) {
readBytes := func(size int) (data []byte, err error) {
data = make([]byte, size)
var n int
if n, err = rand.Read(data); err != nil {
return nil, err
} else if n != size {
return nil, fmt.Errorf("Not enough data. Expected to read: %v bytes, got: %v bytes", size, n)
}
return data, nil
}
// Generate access key.
keyBytes, err := readBytes(accessKeyMaxLen)
if err != nil {
return cred, err
}
for i := 0; i < accessKeyMaxLen; i++ {
keyBytes[i] = alphaNumericTable[keyBytes[i]%alphaNumericTableLen]
}
cred.AccessKey = string(keyBytes)
// Generate secret key.
keyBytes, err = readBytes(secretKeyMaxLen)
if err != nil {
return cred, err
}
cred.SecretKey = string([]byte(base64.StdEncoding.EncodeToString(keyBytes))[:secretKeyMaxLen])
return cred, nil
}
// CreateCredentials returns new credential with the given access key and secret key.
// Error is returned if given access key or secret key are invalid length.
func CreateCredentials(accessKey, secretKey string) (cred Credentials, err error) {
if !IsAccessKeyValid(accessKey) {
return cred, ErrInvalidAccessKeyLength
}
if !isSecretKeyValid(secretKey) {
return cred, ErrInvalidSecretKeyLength
}
cred.AccessKey = accessKey
cred.SecretKey = secretKey
return cred, nil
}