fix: Handle node public key mismatch and show warning (#1720)

* 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.

* feat: Add key mismatch detection to NodeInfoDao

This commit introduces a new feature to the `NodeInfoDao` that detects and handles public key mismatches for existing nodes.

-   A new function `upsertCheckKeyMatch` is added to `NodeInfoDao` that checks for public key changes when upserting a node. If a mismatch is detected, the public key is set to `ERROR_BYTE_STRING`, and a warning is logged.
- The function `upsertCheckKeyMatch` is used instead of `upsert` in `NodeRepository` and in `putAll` inside of `NodeInfoDao`.
-   A new test `testPkcMismatch` is added to `NodeInfoDaoTest` to verify the key mismatch detection.
- Changed `testNodes` to have unique public keys.
- Added `mismatchKey` state to the node model.

* detekt spacing

* Refactor: Correctly handle different node installations in NodeRepository

The logic for detecting different node installations in `NodeRepository.kt` was inverted, this commit fixes the logic to use `!=` instead of `==` to detect if the node number has changed.

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

@@ -103,13 +103,16 @@ class NodeRepository @Inject constructor(
     ).mapLatest { list -> list.map { it.toModel() } }.flowOn(dispatchers.io).conflate()
 
     suspend fun upsert(node: NodeEntity) = withContext(dispatchers.io) {
-        nodeInfoDao.upsert(node)
+        nodeInfoDao.upsertCheckKeyMatch(node)
     }
 
     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 +110,20 @@ interface NodeInfoDao {
     @Upsert
     fun upsert(node: NodeEntity)
 
-    @Insert(onConflict = OnConflictStrategy.REPLACE)
-    fun putAll(nodes: List<NodeEntity>)
+    fun upsertCheckKeyMatch(node: NodeEntity) {
+        val existingNode = getNodeByNum(node.num)
+        if (existingNode != null && existingNode.user.publicKey != node.user.publicKey) {
+            Log.w(TAG, "Node ${node.num} has changed its public key")
+            val user =
+                node.user.toBuilder().setPublicKey(NodeEntity.ERROR_BYTE_STRING).build()
+            node.user = user
+        }
+        upsert(node)
+    }
+    @Transaction
+    fun putAll(nodes: List<NodeEntity>) {
+        nodes.forEach { upsertCheckKeyMatch(it) }
+    }
 
     @Query("DELETE FROM nodes")
     fun clearNodeInfo()
@@ -122,4 +136,7 @@ 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()
     }