From 24f70007624aab3b2daa958a455868fea5d6dd85 Mon Sep 17 00:00:00 2001
From: jbhusson <jonah@elixxir.io>
Date: Wed, 20 Jul 2022 14:32:36 -0400
Subject: [PATCH] Fix payload size, comments from review
---
broadcast/asymmetric.go | 18 ++++++++++++++----
broadcast/broadcastClient.go | 4 ++++
broadcast/processor.go | 14 ++++++++------
broadcast/symmetric.go | 2 +-
4 files changed, 27 insertions(+), 11 deletions(-)
diff --git a/broadcast/asymmetric.go b/broadcast/asymmetric.go
index ed731ff21..8fab1b5a2 100644
--- a/broadcast/asymmetric.go
+++ b/broadcast/asymmetric.go
@@ -8,6 +8,7 @@
package broadcast
import (
+ "encoding/binary"
"github.com/pkg/errors"
"gitlab.com/elixxir/client/cmix"
"gitlab.com/elixxir/client/cmix/message"
@@ -19,6 +20,7 @@ import (
const (
asymmetricBroadcastServiceTag = "AsymmBcast"
asymmCMixSendTag = "AsymmetricBroadcast"
+ internalPayloadSizeLength = 2
)
// MaxAsymmetricPayloadSize returns the maximum size for an asymmetric broadcast payload
@@ -28,20 +30,26 @@ func (bc *broadcastClient) maxAsymmetricPayload() int {
// BroadcastAsymmetric broadcasts the payload to the channel. Requires a healthy network state to send
// Payload must be equal to bc.MaxAsymmetricPayloadSize, and the channel PrivateKey must be passed in
-// When a payload is sent, it is split into partitons of size bc.channel.MaxAsymmetricPayloadSize
-// which are each encrypted using multicastRSA
func (bc *broadcastClient) BroadcastAsymmetric(pk multicastRSA.PrivateKey, payload []byte, cMixParams cmix.CMIXParams) (
id.Round, ephemeral.Id, error) {
+ // Confirm network health
if !bc.net.IsHealthy() {
return 0, ephemeral.Id{}, errors.New(errNetworkHealth)
}
- if len(payload) != bc.MaxAsymmetricPayloadSize() {
+ // Check payload size
+ if len(payload) > bc.MaxAsymmetricPayloadSize() {
return 0, ephemeral.Id{},
errors.Errorf(errPayloadSize, len(payload), bc.maxAsymmetricPayload())
}
+ payloadLength := uint16(len(payload))
- encryptedPayload, mac, fp, err := bc.channel.EncryptAsymmetric(payload, pk, bc.rng.GetStream())
+ finalPayload := make([]byte, bc.maxAsymmetricPayloadSizeRaw())
+ binary.BigEndian.PutUint16(finalPayload[:internalPayloadSizeLength], payloadLength)
+ copy(finalPayload[internalPayloadSizeLength:], payload)
+
+ // Encrypt payload
+ encryptedPayload, mac, fp, err := bc.channel.EncryptAsymmetric(finalPayload, pk, bc.rng.GetStream())
if err != nil {
return 0, ephemeral.Id{}, errors.WithMessage(err, "Failed to encrypt asymmetric broadcast message")
}
@@ -56,7 +64,9 @@ func (bc *broadcastClient) BroadcastAsymmetric(pk multicastRSA.PrivateKey, paylo
cMixParams.DebugTag = asymmCMixSendTag
}
+ // Create payload sized for sending over cmix
sizedPayload := make([]byte, bc.net.GetMaxMessageLength())
+ // Read random data into sized payload
_, err = bc.rng.GetStream().Read(sizedPayload)
if err != nil {
return 0, ephemeral.Id{}, errors.WithMessage(err, "Failed to add random data to sized broadcast")
diff --git a/broadcast/broadcastClient.go b/broadcast/broadcastClient.go
index c80f4a50e..6e1c7391c 100644
--- a/broadcast/broadcastClient.go
+++ b/broadcast/broadcastClient.go
@@ -102,5 +102,9 @@ func (bc *broadcastClient) MaxPayloadSize() int {
}
func (bc *broadcastClient) MaxAsymmetricPayloadSize() int {
+ return bc.maxAsymmetricPayloadSizeRaw() - internalPayloadSizeLength
+}
+
+func (bc *broadcastClient) maxAsymmetricPayloadSizeRaw() int {
return bc.channel.MaxAsymmetricPayloadSize()
}
diff --git a/broadcast/processor.go b/broadcast/processor.go
index b747eac00..651974c4c 100644
--- a/broadcast/processor.go
+++ b/broadcast/processor.go
@@ -8,6 +8,7 @@
package broadcast
import (
+ "encoding/binary"
jww "github.com/spf13/jwalterweatherman"
"gitlab.com/elixxir/client/cmix/identity/receptionID"
"gitlab.com/elixxir/client/cmix/rounds"
@@ -35,14 +36,15 @@ func (p *processor) Process(msg format.Message,
var err error
switch p.method {
case Asymmetric:
- // We use sized broadcast to fill any remaining bytes in the cmix payload, decode it here
- encPartSize := p.c.RsaPubKey.Size() // Size of each chunk returned by multicast RSA encryption
- encodedMessage := msg.GetContents()[:encPartSize]
- payload, err = p.c.DecryptAsymmetric(encodedMessage)
- if err != nil {
- jww.ERROR.Printf(errDecrypt, p.c.ReceptionID, p.c.Name, err)
+ encPartSize := p.c.RsaPubKey.Size() // Size returned by multicast RSA encryption
+ encodedMessage := msg.GetContents()[:encPartSize] // Only one message is encoded, rest of it is random data
+ decodedMessage, decryptErr := p.c.DecryptAsymmetric(encodedMessage)
+ if decryptErr != nil {
+ jww.ERROR.Printf(errDecrypt, p.c.ReceptionID, p.c.Name, decryptErr)
return
}
+ size := binary.BigEndian.Uint16(decodedMessage[:internalPayloadSizeLength])
+ payload = decodedMessage[internalPayloadSizeLength : size+internalPayloadSizeLength]
case Symmetric:
payload, err = p.c.DecryptSymmetric(msg.GetContents(), msg.GetMac(), msg.GetKeyFP())
diff --git a/broadcast/symmetric.go b/broadcast/symmetric.go
index 10ca5a5b3..e9b96f75c 100644
--- a/broadcast/symmetric.go
+++ b/broadcast/symmetric.go
@@ -19,7 +19,7 @@ import (
const (
// symmetricClient.Broadcast
errNetworkHealth = "cannot send broadcast when the network is not healthy"
- errPayloadSize = "size of payload %d must be %d"
+ errPayloadSize = "size of payload %d must be less than %d"
errBroadcastMethodType = "cannot call %s broadcast using %s channel"
)
--
GitLab