launcher: a patched Waze, signed with someone else's key, loses the red X and can start as the map app

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarLauncher.kt

@@ -239,6 +239,7 @@ internal fun launchEntry(entry: Entry, navigator: CarNavigator, frame: CarEnviro
 /** The app launcher: every app as an icon grid, grouped Phone, Maps, Music, Messaging, Web, Screen sharing, Settings. */
 @Composable
 fun CarLauncher() {
+    val context = LocalContext.current
     val navigator = LocalCarNavigator.current
     val frame by CarEnvironment.frame.collectAsState()
 
@@ -254,7 +255,7 @@ fun CarLauncher() {
         val id = entry.componentId
         return Tile(
             entry.label, entry.icon, entry.builtIn?.glyph,
-            broken = pkg != null && (KnownApps.isBroken(pkg) || (entry.template != null && KnownApps.screenBroken(pkg))),
+            broken = pkg != null && (KnownApps.isBroken(context, pkg) || (entry.template != null && KnownApps.screenBroken(pkg))),
             onLongClick = id?.let { { navigator.showAppMenu(it) } },
         ) { openApp(entry, id?.let { running[it] }, navigator, frame) }
     }

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarServices.kt

@@ -178,7 +178,7 @@ object CarServices {
             _hasNavApps.value = navApps.isNotEmpty()
             // Never auto-pick one already known to fail outright - a driver who plugs in should
             // land on a map, not on the one tile marked with a red X.
-            val candidates = navApps.filterNot { KnownApps.isBroken(it.component.packageName) }
+            val candidates = navApps.filterNot { KnownApps.isBroken(ctx, it.component.packageName) }
             val last = CarSettings.lastNav.value
             // The one used last, or - first run, nothing on record yet - whichever comes first:
             // a driver who plugs in for the first time shouldn't have to go pick one by hand

gearslip/src/main/java/app/seb3thehacker/gearslip/host/KnownApps.kt

@@ -1,5 +1,9 @@
 package app.seb3thehacker.gearslip.host
 
+import android.content.Context
+import android.content.pm.PackageManager
+import java.security.MessageDigest
+
 /**
  * Apps that have been run through Gearslip from start to finish and behave. The launcher marks
  * them so a driver can pick something that works without finding out at the wheel.
@@ -65,7 +69,30 @@ object KnownApps {
         "com.generalmagic.magicearth",       // Magic Earth: never gets past connecting
     )
 
-    fun isBroken(packageName: String): Boolean = packageName in broken
+    fun isBroken(context: Context, packageName: String): Boolean =
+        packageName in broken && !patched(context, packageName)
+
+    /**
+     * The certificate each broken app's own publisher signs it with. A copy signed with another
+     * key has been patched to accept Gearslip, like Waze with the waze-gearslip Morphe patch, and
+     * works.
+     */
+    private val officialSigners = mapOf(
+        "com.waze" to "03637f6c5d8f604e6fdb79a6ffbfa578de4e318f8da22fc6106665247f8807d7",
+    )
+
+    /** Whether the installed copy is signed by someone other than its publisher. */
+    private fun patched(context: Context, packageName: String): Boolean {
+        val official = officialSigners[packageName] ?: return false
+        val signers = runCatching {
+            context.packageManager.getPackageInfo(packageName, PackageManager.GET_SIGNING_CERTIFICATES)
+                .signingInfo?.apkContentsSigners
+        }.getOrNull() ?: return false
+        val sha256 = MessageDigest.getInstance("SHA-256")
+        return signers.isNotEmpty() && signers.none { cert ->
+            sha256.digest(cert.toByteArray()).joinToString("") { "%02x".format(it) } == official
+        }
+    }
 
     /**
      * Shown on the launcher with a yellow mark: starts and can be used, but not cleanly enough to