mirror of https://github.com/grafana/grafana.git
149 lines
3.6 KiB
Go
149 lines
3.6 KiB
Go
package util
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import (
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"bytes"
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"crypto/aes"
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"crypto/cipher"
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"crypto/rand"
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"crypto/sha256"
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"encoding/base64"
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"errors"
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"fmt"
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"io"
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"golang.org/x/crypto/pbkdf2"
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)
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const (
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saltLength = 8
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aesCfb = "aes-cfb"
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aesGcm = "aes-gcm"
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encryptionAlgorithmDelimiter = '*'
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)
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// Decrypt decrypts a payload with a given secret.
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// DEPRECATED. Do not use it.
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// Use secrets.Service instead.
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func Decrypt(payload []byte, secret string) ([]byte, error) {
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alg, payload, err := deriveEncryptionAlgorithm(payload)
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if err != nil {
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return nil, err
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}
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if len(payload) < saltLength {
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return nil, fmt.Errorf("unable to compute salt")
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}
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salt := payload[:saltLength]
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key, err := encryptionKeyToBytes(secret, string(salt))
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if err != nil {
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return nil, err
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}
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block, err := aes.NewCipher(key)
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if err != nil {
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return nil, err
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}
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switch alg {
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case aesGcm:
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return decryptGCM(block, payload)
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default:
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return decryptCFB(block, payload)
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}
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}
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func deriveEncryptionAlgorithm(payload []byte) (string, []byte, error) {
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if len(payload) == 0 {
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return "", nil, fmt.Errorf("unable to derive encryption algorithm")
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}
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if payload[0] != encryptionAlgorithmDelimiter {
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return aesCfb, payload, nil // backwards compatibility
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}
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payload = payload[1:]
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algDelim := bytes.Index(payload, []byte{encryptionAlgorithmDelimiter})
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if algDelim == -1 {
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return aesCfb, payload, nil // backwards compatibility
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}
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algB64 := payload[:algDelim]
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payload = payload[algDelim+1:]
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alg := make([]byte, base64.RawStdEncoding.DecodedLen(len(algB64)))
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_, err := base64.RawStdEncoding.Decode(alg, algB64)
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if err != nil {
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return "", nil, err
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}
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return string(alg), payload, nil
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}
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func decryptGCM(block cipher.Block, payload []byte) ([]byte, error) {
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gcm, err := cipher.NewGCM(block)
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if err != nil {
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return nil, err
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}
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nonce := payload[saltLength : saltLength+gcm.NonceSize()]
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ciphertext := payload[saltLength+gcm.NonceSize():]
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return gcm.Open(nil, nonce, ciphertext, nil)
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}
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func decryptCFB(block cipher.Block, payload []byte) ([]byte, error) {
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// The IV needs to be unique, but not secure. Therefore it's common to
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// include it at the beginning of the ciphertext.
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if len(payload) < aes.BlockSize {
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return nil, errors.New("payload too short")
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}
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iv := payload[saltLength : saltLength+aes.BlockSize]
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payload = payload[saltLength+aes.BlockSize:]
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payloadDst := make([]byte, len(payload))
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stream := cipher.NewCFBDecrypter(block, iv)
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// XORKeyStream can work in-place if the two arguments are the same.
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stream.XORKeyStream(payloadDst, payload)
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return payloadDst, nil
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}
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// Encrypt encrypts a payload with a given secret.
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// DEPRECATED. Do not use it.
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// Use secrets.Service instead.
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func Encrypt(payload []byte, secret string) ([]byte, error) {
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salt, err := GetRandomString(saltLength)
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if err != nil {
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return nil, err
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}
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key, err := encryptionKeyToBytes(secret, salt)
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if err != nil {
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return nil, err
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}
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block, err := aes.NewCipher(key)
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if err != nil {
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return nil, err
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}
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// The IV needs to be unique, but not secure. Therefore it's common to
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// include it at the beginning of the ciphertext.
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ciphertext := make([]byte, saltLength+aes.BlockSize+len(payload))
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copy(ciphertext[:saltLength], salt)
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iv := ciphertext[saltLength : saltLength+aes.BlockSize]
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if _, err := io.ReadFull(rand.Reader, iv); err != nil {
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return nil, err
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}
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stream := cipher.NewCFBEncrypter(block, iv)
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stream.XORKeyStream(ciphertext[saltLength+aes.BlockSize:], payload)
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return ciphertext, nil
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}
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// Key needs to be 32bytes
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func encryptionKeyToBytes(secret, salt string) ([]byte, error) {
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return pbkdf2.Key([]byte(secret), []byte(salt), 10000, 32, sha256.New), nil
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}
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