openpgp/packet: support crypto.Decrypter in EncryptedKey.Decrypt
Fixes golang/go#33301
Change-Id: I74a389367d34d4718d70349794027ed9f1eca370
GitHub-Last-Rev: 6d95cdf63248a54b134027ed49641c204187f188
GitHub-Pull-Request: golang/crypto#94
Reviewed-on: https://go-review.googlesource.com/c/crypto/+/189497
Reviewed-by: Filippo Valsorda <filippo@golang.org>
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
diff --git a/openpgp/packet/encrypted_key.go b/openpgp/packet/encrypted_key.go
index 02b372c..6d76397 100644
--- a/openpgp/packet/encrypted_key.go
+++ b/openpgp/packet/encrypted_key.go
@@ -5,6 +5,7 @@
package packet
import (
+ "crypto"
"crypto/rsa"
"encoding/binary"
"io"
@@ -78,8 +79,9 @@
// padding oracle attacks.
switch priv.PubKeyAlgo {
case PubKeyAlgoRSA, PubKeyAlgoRSAEncryptOnly:
- k := priv.PrivateKey.(*rsa.PrivateKey)
- b, err = rsa.DecryptPKCS1v15(config.Random(), k, padToKeySize(&k.PublicKey, e.encryptedMPI1.bytes))
+ // Supports both *rsa.PrivateKey and crypto.Decrypter
+ k := priv.PrivateKey.(crypto.Decrypter)
+ b, err = k.Decrypt(config.Random(), padToKeySize(k.Public().(*rsa.PublicKey), e.encryptedMPI1.bytes), nil)
case PubKeyAlgoElGamal:
c1 := new(big.Int).SetBytes(e.encryptedMPI1.bytes)
c2 := new(big.Int).SetBytes(e.encryptedMPI2.bytes)
diff --git a/openpgp/packet/encrypted_key_test.go b/openpgp/packet/encrypted_key_test.go
index f2fcf4d..ecb22bc 100644
--- a/openpgp/packet/encrypted_key_test.go
+++ b/openpgp/packet/encrypted_key_test.go
@@ -6,9 +6,11 @@
import (
"bytes"
+ "crypto"
"crypto/rsa"
"encoding/hex"
"fmt"
+ "io"
"math/big"
"testing"
)
@@ -80,6 +82,73 @@
}
}
+type rsaDecrypter struct {
+ rsaPrivateKey *rsa.PrivateKey
+ decryptCount int
+}
+
+func (r *rsaDecrypter) Public() crypto.PublicKey {
+ return &r.rsaPrivateKey.PublicKey
+}
+
+func (r *rsaDecrypter) Decrypt(rand io.Reader, msg []byte, opts crypto.DecrypterOpts) (plaintext []byte, err error) {
+ r.decryptCount++
+ return r.rsaPrivateKey.Decrypt(rand, msg, opts)
+}
+
+func TestRSADecrypter(t *testing.T) {
+ const encryptedKeyHex = "c18c032a67d68660df41c70104005789d0de26b6a50c985a02a13131ca829c413a35d0e6fa8d6842599252162808ac7439c72151c8c6183e76923fe3299301414d0c25a2f06a2257db3839e7df0ec964773f6e4c4ac7ff3b48c444237166dd46ba8ff443a5410dc670cb486672fdbe7c9dfafb75b4fea83af3a204fe2a7dfa86bd20122b4f3d2646cbeecb8f7be8"
+
+ const expectedKeyHex = "d930363f7e0308c333b9618617ea728963d8df993665ae7be1092d4926fd864b"
+
+ p, err := Read(readerFromHex(encryptedKeyHex))
+ if err != nil {
+ t.Errorf("error from Read: %s", err)
+ return
+ }
+ ek, ok := p.(*EncryptedKey)
+ if !ok {
+ t.Errorf("didn't parse an EncryptedKey, got %#v", p)
+ return
+ }
+
+ if ek.KeyId != 0x2a67d68660df41c7 || ek.Algo != PubKeyAlgoRSA {
+ t.Errorf("unexpected EncryptedKey contents: %#v", ek)
+ return
+ }
+
+ customDecrypter := &rsaDecrypter{
+ rsaPrivateKey: encryptedKeyRSAPriv,
+ }
+
+ customKeyPriv := &PrivateKey{
+ PublicKey: PublicKey{
+ PubKeyAlgo: PubKeyAlgoRSA,
+ },
+ PrivateKey: customDecrypter,
+ }
+
+ err = ek.Decrypt(customKeyPriv, nil)
+ if err != nil {
+ t.Errorf("error from Decrypt: %s", err)
+ return
+ }
+
+ if ek.CipherFunc != CipherAES256 {
+ t.Errorf("unexpected EncryptedKey contents: %#v", ek)
+ return
+ }
+
+ keyHex := fmt.Sprintf("%x", ek.Key)
+ if keyHex != expectedKeyHex {
+ t.Errorf("bad key, got %s want %s", keyHex, expectedKeyHex)
+ }
+
+ if customDecrypter.decryptCount != 1 {
+ t.Errorf("Expected customDecrypter.Decrypt() to be called 1 time, but was called %d times", customDecrypter.decryptCount)
+ }
+}
+
func TestEncryptingEncryptedKey(t *testing.T) {
key := []byte{1, 2, 3, 4}
const expectedKeyHex = "01020304"
diff --git a/openpgp/packet/private_key.go b/openpgp/packet/private_key.go
index 6f8ec09..81abb7c 100644
--- a/openpgp/packet/private_key.go
+++ b/openpgp/packet/private_key.go
@@ -31,7 +31,7 @@
encryptedData []byte
cipher CipherFunction
s2k func(out, in []byte)
- PrivateKey interface{} // An *{rsa|dsa|ecdsa}.PrivateKey or a crypto.Signer.
+ PrivateKey interface{} // An *{rsa|dsa|ecdsa}.PrivateKey or crypto.Signer/crypto.Decrypter (Decryptor RSA only).
sha1Checksum bool
iv []byte
}
