From c3d60342f443d1980dca86a22d703b9370cdd702 Mon Sep 17 00:00:00 2001
From: GUVWAF <78759985+GUVWAF@users.noreply.github.com>
Date: Thu, 5 Dec 2024 03:00:19 +0100
Subject: [PATCH] Don't use channel index for encrypted packet (#5509)

* Don't use channel index for encrypted packet

* Remove assert in `getKey`, set invalid key length
So encrypting will fail without reboot

* Reset channel to 0 when unable to encrypt
Such that the NAK doesn't use the failing channel hash
---
 src/mesh/Channels.cpp       | 3 +--
 src/mesh/FloodingRouter.cpp | 3 ++-
 src/mesh/Router.cpp         | 1 +
 3 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/mesh/Channels.cpp b/src/mesh/Channels.cpp
index cfaff7640a..4bdd9e674a 100644
--- a/src/mesh/Channels.cpp
+++ b/src/mesh/Channels.cpp
@@ -178,12 +178,11 @@ CryptoKey Channels::getKey(ChannelIndex chIndex)
 {
     meshtastic_Channel &ch = getByIndex(chIndex);
     const meshtastic_ChannelSettings &channelSettings = ch.settings;
-    assert(ch.has_settings);
 
     CryptoKey k;
     memset(k.bytes, 0, sizeof(k.bytes)); // In case the user provided a short key, we want to pad the rest with zeros
 
-    if (ch.role == meshtastic_Channel_Role_DISABLED) {
+    if (!ch.has_settings || ch.role == meshtastic_Channel_Role_DISABLED) {
         k.length = -1; // invalid
     } else {
         memcpy(k.bytes, channelSettings.psk.bytes, channelSettings.psk.size);
diff --git a/src/mesh/FloodingRouter.cpp b/src/mesh/FloodingRouter.cpp
index e959297bff..e29c596df4 100644
--- a/src/mesh/FloodingRouter.cpp
+++ b/src/mesh/FloodingRouter.cpp
@@ -36,7 +36,8 @@ bool FloodingRouter::shouldFilterReceived(const meshtastic_MeshPacket *p)
         if (isRepeated) {
             LOG_DEBUG("Repeated reliable tx");
             if (!perhapsRebroadcast(p) && isToUs(p) && p->want_ack) {
-                sendAckNak(meshtastic_Routing_Error_NONE, getFrom(p), p->id, p->channel, 0);
+                // FIXME - channel index should be used, but the packet is still encrypted here
+                sendAckNak(meshtastic_Routing_Error_NONE, getFrom(p), p->id, 0, 0);
             }
         }
 
diff --git a/src/mesh/Router.cpp b/src/mesh/Router.cpp
index e9c62ff279..e714ef2154 100644
--- a/src/mesh/Router.cpp
+++ b/src/mesh/Router.cpp
@@ -271,6 +271,7 @@ ErrorCode Router::send(meshtastic_MeshPacket *p)
         auto encodeResult = perhapsEncode(p);
         if (encodeResult != meshtastic_Routing_Error_NONE) {
             packetPool.release(p_decoded);
+            p->channel = 0; // Reset the channel to 0, so we don't use the failing hash again
             abortSendAndNak(encodeResult, p);
             return encodeResult; // FIXME - this isn't a valid ErrorCode
         }