func (b *AccountManagerBinding) getOTP(db gorp.SqlExecutor, kms security.KMS, accountID snowflake.Snowflake) (*proto.OTP, error) {
encryptedOTP, err := b.getRawOTP(db, accountID)
if err != nil {
return nil, err
}
key := security.ManagedKey{
KeyType: OTPKeyType,
IV: encryptedOTP.IV,
Ciphertext: encryptedOTP.EncryptedKey,
ContextKey: "account",
ContextValue: accountID.String(),
}
if err := kms.DecryptKey(&key); err != nil {
return nil, err
}
uriBytes, err := security.DecryptGCM(&key, encryptedOTP.IV, encryptedOTP.Digest, encryptedOTP.EncryptedURI, nil)
if err != nil {
return nil, err
}
otp := &proto.OTP{
URI: string(uriBytes),
Validated: encryptedOTP.Validated,
}
return otp, nil
}
func DecryptMessage(msg Message, auths map[string]*security.ManagedKey) (Message, error) {
if msg.EncryptionKeyID == "" {
return msg, nil
}
keyVersion := 0
keyID := msg.EncryptionKeyID
if strings.HasPrefix(keyID, "v1") {
keyVersion = 1
keyID = keyID[3:]
}
auth, ok := auths[keyID]
if !ok {
return msg, nil
}
if auth.Encrypted() {
return msg, security.ErrKeyMustBeDecrypted
}
parts := strings.Split(msg.Content, "/")
if len(parts) != 2 {
fmt.Printf("bad content: %s\n", msg.Content)
return msg, fmt.Errorf("message corrupted")
}
digest, err := base64.URLEncoding.DecodeString(parts[0])
if err != nil {
return msg, err
}
ciphertext, err := base64.URLEncoding.DecodeString(parts[1])
if err != nil {
return msg, err
}
plaintext, err := security.DecryptGCM(
auth, []byte(msg.ID.String()), digest, ciphertext, []byte(msg.Sender.ID))
if err != nil {
return msg, fmt.Errorf("message decrypt: %s", err)
}
switch keyVersion {
case 0:
// unversioned keys briefly existed when private rooms first rolled out
msg.Content = string(plaintext)
case 1:
// v1 keys embed an encrypted partial message, hiding the sender and content
var payload Message
if err := json.Unmarshal(plaintext, &payload); err != nil {
return msg, fmt.Errorf("message corrupted: %s", err)
}
msg.Sender = payload.Sender
msg.Content = payload.Content
}
return msg, nil
}
func TestGrants(t *testing.T) {
Convey("Grant a capability on a room", t, func() {
kms := security.LocalKMS()
kms.SetMasterKey(make([]byte, security.AES256.KeySize()))
ctx := scope.New()
client := &proto.Client{Agent: &proto.Agent{}}
client.FromRequest(ctx, &http.Request{})
backend := &mock.TestBackend{}
room, err := backend.CreateRoom(ctx, kms, true, "test")
So(err, ShouldBeNil)
rkey, err := room.MessageKey(ctx)
So(err, ShouldBeNil)
mkey := rkey.ManagedKey()
So(kms.DecryptKey(&mkey), ShouldBeNil)
// Sign in as alice and send an encrypted message with aliceSendTime
// as the nonce.
aliceSendTime := time.Now()
msgNonce := []byte(snowflake.NewFromTime(aliceSendTime).String())
aliceKey := &security.ManagedKey{
KeyType: security.AES256,
Plaintext: make([]byte, security.AES256.KeySize()),
}
grant, err := security.GrantSharedSecretCapability(aliceKey, rkey.Nonce(), nil, mkey.Plaintext)
So(err, ShouldBeNil)
alice := mock.TestSession("Alice", "A1", "ip1")
_, err = room.Join(ctx, alice)
So(err, ShouldBeNil)
msg := proto.Message{
ID: snowflake.NewFromTime(aliceSendTime),
UnixTime: proto.Time(aliceSendTime),
Content: "hello",
}
iv, err := base64.URLEncoding.DecodeString(grant.CapabilityID())
So(err, ShouldBeNil)
payload := grant.EncryptedPayload()
So(aliceKey.BlockCrypt(iv, aliceKey.Plaintext, payload, false), ShouldBeNil)
key := &security.ManagedKey{
KeyType: security.AES128,
}
So(json.Unmarshal(aliceKey.Unpad(payload), &key.Plaintext), ShouldBeNil)
digest, ciphertext, err := security.EncryptGCM(
key, msgNonce, []byte(msg.Content), []byte("Alice"))
So(err, ShouldBeNil)
digestStr := base64.URLEncoding.EncodeToString(digest)
cipherStr := base64.URLEncoding.EncodeToString(ciphertext)
msg.Content = digestStr + "/" + cipherStr
_, err = room.Send(ctx, alice, msg)
So(err, ShouldBeNil)
// Now sign in as bob and decrypt the message.
bobKey := &security.ManagedKey{
KeyType: security.AES256,
Plaintext: make([]byte, security.AES256.KeySize()),
}
//bobKey.Plaintext[0] = 1
grant, err = security.GrantSharedSecretCapability(bobKey, rkey.Nonce(), nil, mkey.Plaintext)
So(err, ShouldBeNil)
iv, err = base64.URLEncoding.DecodeString(grant.CapabilityID())
So(err, ShouldBeNil)
payload = grant.EncryptedPayload()
So(bobKey.BlockCrypt(iv, bobKey.Plaintext, payload, false), ShouldBeNil)
key = &security.ManagedKey{
KeyType: security.AES128,
}
So(json.Unmarshal(bobKey.Unpad(payload), &key.Plaintext), ShouldBeNil)
bob := mock.TestSession("Bob", "B1", "ip2")
_, err = room.Join(ctx, bob)
So(err, ShouldBeNil)
log, err := room.Latest(ctx, 1, 0)
So(err, ShouldBeNil)
So(len(log), ShouldEqual, 1)
msg = log[0]
parts := strings.Split(msg.Content, "/")
So(len(parts), ShouldEqual, 2)
digest, err = base64.URLEncoding.DecodeString(parts[0])
So(err, ShouldBeNil)
ciphertext, err = base64.URLEncoding.DecodeString(parts[1])
So(err, ShouldBeNil)
plaintext, err := security.DecryptGCM(key, msgNonce, digest, ciphertext, []byte("Alice"))
So(err, ShouldBeNil)
So(string(plaintext), ShouldEqual, "hello")
})
}