Emil Tullstedt
81 lines
2.0 KiB
Go
81 lines
2.0 KiB
Go
package secrets
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import (
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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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"errors"
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"io"
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"github.com/grafana/grafana/pkg/util"
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"golang.org/x/crypto/pbkdf2"
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)
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const saltLength = 8
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// Decrypt decrypts a payload with a given secret.
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func decrypt(payload, secret []byte) ([]byte, error) {
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salt := payload[:saltLength]
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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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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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func encrypt(payload, secret []byte) ([]byte, error) {
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salt, err := util.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, []byte(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 []byte) ([]byte, error) {
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return pbkdf2.Key(secret, salt, 10000, 32, sha256.New), nil
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}
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