Handle node public key mismatch and show warning

- Add a mismatchKey flag to Node and MessageTopBar to indicate a public key mismatch.
- Set the public key to a default error value (all zeros) when a node's public key changes.
- Display a warning in the MessageTopBar when a key mismatch is detected in PKC.
- Only clear all nodes when a different mynode number is present.

app/src/main/java/com/geeksville/mesh/database/NodeRepository.kt

@@ -107,9 +107,12 @@ class NodeRepository @Inject constructor(
     }
 
     suspend fun installNodeDB(mi: MyNodeEntity, nodes: List<NodeEntity>) = withContext(dispatchers.io) {
+        val isDifferentNode = myNodeInfo.value?.myNodeNum == mi.myNodeNum
         nodeInfoDao.clearMyNodeInfo()
         nodeInfoDao.setMyNodeInfo(mi) // set MyNodeEntity first
-        nodeInfoDao.clearNodeInfo()
+        if (isDifferentNode) {
+            nodeInfoDao.clearNodeInfo()
+        }
         nodeInfoDao.putAll(nodes)
     }
 

app/src/main/java/com/geeksville/mesh/database/dao/NodeInfoDao.kt

@@ -17,6 +17,7 @@
 
 package com.geeksville.mesh.database.dao
 
+import android.util.Log
 import androidx.room.Dao
 import androidx.room.Insert
 import androidx.room.MapColumn
@@ -26,10 +27,11 @@ import androidx.room.Transaction
 import androidx.room.Upsert
 import com.geeksville.mesh.database.entity.MetadataEntity
 import com.geeksville.mesh.database.entity.MyNodeEntity
-import com.geeksville.mesh.database.entity.NodeWithRelations
 import com.geeksville.mesh.database.entity.NodeEntity
+import com.geeksville.mesh.database.entity.NodeWithRelations
 import kotlinx.coroutines.flow.Flow
 
+private const val TAG = "NodeInfoDao"
 @Suppress("TooManyFunctions")
 @Dao
 interface NodeInfoDao {
@@ -108,8 +110,22 @@ interface NodeInfoDao {
     @Upsert
     fun upsert(node: NodeEntity)
 
-    @Insert(onConflict = OnConflictStrategy.REPLACE)
-    fun putAll(nodes: List<NodeEntity>)
+    @Transaction
+    fun putAll(nodes: List<NodeEntity>) {
+        val existingNodes = nodes.mapNotNull {
+            getNodeByNum(it.num)
+        }
+        nodes.forEach { newNode ->
+            val existingNode = existingNodes.firstOrNull { it.num == newNode.num }
+            if (existingNode != null && existingNode.user.publicKey != newNode.user.publicKey) {
+                Log.w(TAG, "Node ${newNode.num} has changed its public key")
+                val user =
+                    newNode.user.toBuilder().setPublicKey(NodeEntity.ERROR_BYTE_STRING).build()
+                newNode.user = user
+            }
+            upsert(newNode)
+        }
+    }
 
     @Query("DELETE FROM nodes")
     fun clearNodeInfo()
@@ -122,4 +138,7 @@ interface NodeInfoDao {
 
     @Query("DELETE FROM metadata WHERE num=:num")
     fun deleteMetadata(num: Int)
+
+    @Query("SELECT * FROM nodes WHERE num = :num")
+    fun getNodeByNum(num: Int): NodeEntity?
 }

app/src/main/java/com/geeksville/mesh/database/entity/NodeEntity.kt

@@ -151,7 +151,7 @@ data class NodeEntity(
 
     val isUnknownUser get() = user.hwModel == MeshProtos.HardwareModel.UNSET
     val hasPKC get() = !user.publicKey.isEmpty
-    val errorByteString: ByteString get() = ByteString.copyFrom(ByteArray(32) { 0 })
+    val errorByteString: ByteString get() = ERROR_BYTE_STRING
 
     fun setPosition(p: MeshProtos.Position, defaultTime: Int = currentTime()) {
         position = p.copy { time = if (p.time != 0) p.time else defaultTime }
@@ -174,6 +174,7 @@ data class NodeEntity(
         fun degD(i: Int) = i * 1e-7
         fun degI(d: Double) = (d * 1e7).toInt()
 
+        val ERROR_BYTE_STRING: ByteString = ByteString.copyFrom(ByteArray(32) { 0 })
         fun currentTime() = (System.currentTimeMillis() / 1000).toInt()
     }
 

app/src/main/java/com/geeksville/mesh/model/Node.kt

@@ -24,10 +24,10 @@ import com.geeksville.mesh.PaxcountProtos
 import com.geeksville.mesh.TelemetryProtos.DeviceMetrics
 import com.geeksville.mesh.TelemetryProtos.EnvironmentMetrics
 import com.geeksville.mesh.TelemetryProtos.PowerMetrics
+import com.geeksville.mesh.database.entity.NodeEntity
 import com.geeksville.mesh.util.GPSFormat
 import com.geeksville.mesh.util.latLongToMeter
 import com.geeksville.mesh.util.toDistanceString
-import com.google.protobuf.ByteString
 
 @Suppress("MagicNumber")
 data class Node(
@@ -59,8 +59,7 @@ data class Node(
 
     val isUnknownUser get() = user.hwModel == MeshProtos.HardwareModel.UNSET
     val hasPKC get() = !user.publicKey.isEmpty
-    val errorByteString: ByteString get() = ByteString.copyFrom(ByteArray(32) { 0 })
-    val mismatchKey get() = user.publicKey == errorByteString
+    val mismatchKey get() = user.publicKey == NodeEntity.ERROR_BYTE_STRING
 
     val hasEnvironmentMetrics: Boolean
         get() = environmentMetrics != EnvironmentMetrics.getDefaultInstance()

app/src/main/java/com/geeksville/mesh/ui/message/Message.kt

@@ -184,6 +184,8 @@ internal fun MessageScreen(
         DataPacket.ID_BROADCAST -> channelName
         else -> viewModel.getUser(nodeId).longName
     }
+    val mismatchKey =
+        DataPacket.PKC_CHANNEL_INDEX == channelIndex && viewModel.getNode(nodeId).mismatchKey
 
 //    if (channelIndex != DataPacket.PKC_CHANNEL_INDEX && nodeId != DataPacket.ID_BROADCAST) {
 //        subtitle = "(ch: $channelIndex - $channelName)"
@@ -242,7 +244,7 @@ internal fun MessageScreen(
                     }
                 }
             } else {
-                MessageTopBar(title, channelIndex, onNavigateBack)
+                MessageTopBar(title, channelIndex, mismatchKey, onNavigateBack)
             }
         },
         bottomBar = {
@@ -368,6 +370,7 @@ private fun ActionModeTopBar(
 private fun MessageTopBar(
     title: String,
     channelIndex: Int?,
+    mismatchKey: Boolean = false,
     onNavigateBack: () -> Unit
 ) = TopAppBar(
     title = { Text(text = title) },
@@ -381,7 +384,7 @@ private fun MessageTopBar(
     },
     actions = {
         if (channelIndex == DataPacket.PKC_CHANNEL_INDEX) {
-            NodeKeyStatusIcon(hasPKC = true, mismatchKey = false)
+            NodeKeyStatusIcon(hasPKC = true, mismatchKey = mismatchKey)
         }
     }
 )