From 47e918bc9272fcd2909d51c277e0de0687b60883 Mon Sep 17 00:00:00 2001
From: topjohnwu <topjohnwu@gmail.com>
Date: Mon, 1 Jul 2024 03:20:09 -0700
Subject: [PATCH] Fix vbmeta.img tar patching

---
 .../magisk/core/tasks/MagiskInstaller.kt      | 27 ++++++++++---------
 1 file changed, 15 insertions(+), 12 deletions(-)

diff --git a/app/src/main/java/com/topjohnwu/magisk/core/tasks/MagiskInstaller.kt b/app/src/main/java/com/topjohnwu/magisk/core/tasks/MagiskInstaller.kt
index b149320ac..accb72f3a 100644
--- a/app/src/main/java/com/topjohnwu/magisk/core/tasks/MagiskInstaller.kt
+++ b/app/src/main/java/com/topjohnwu/magisk/core/tasks/MagiskInstaller.kt
@@ -226,10 +226,10 @@ abstract class MagiskInstallImpl protected constructor(
         tarOut: TarArchiveOutputStream
     ): BootItem {
         console.add("- Processing tar file")
-        lateinit var entry: TarArchiveEntry
+        var entry: TarArchiveEntry? = tarIn.nextEntry
 
-        fun decompressedStream(): InputStream {
-            val stream = if (entry.name.endsWith(".lz4"))
+        fun TarArchiveEntry.decompressedStream(): InputStream {
+            val stream = if (name.endsWith(".lz4"))
                 FramedLZ4CompressorInputStream(tarIn, true) else tarIn
             return NoAvailableStream(stream)
         }
@@ -238,9 +238,7 @@ abstract class MagiskInstallImpl protected constructor(
         var initBoot: BootItem? = null
         var recovery: BootItem? = null
 
-        while (true) {
-            entry = tarIn.nextEntry ?: break
-
+        while (entry != null) {
             val bootItem: BootItem?
             if (entry.name.startsWith("boot.img")) {
                 bootItem = BootItem(entry)
@@ -257,9 +255,9 @@ abstract class MagiskInstallImpl protected constructor(
 
             if (bootItem != null) {
                 console.add("-- Extracting: ${bootItem.name}")
-                decompressedStream().copyAndCloseOut(bootItem.file.newOutputStream())
+                entry.decompressedStream().copyAndCloseOut(bootItem.file.newOutputStream())
             } else if (entry.name.contains("vbmeta.img")) {
-                val rawData = decompressedStream().readBytes()
+                val rawData = entry.decompressedStream().readBytes()
                 // Valid vbmeta.img should be at least 256 bytes
                 if (rawData.size < 256)
                     continue
@@ -274,23 +272,28 @@ abstract class MagiskInstallImpl protected constructor(
                 // AVB_VBMETA_IMAGE_FLAGS_VERIFICATION_DISABLED
                 ByteBuffer.wrap(rawData).putInt(120, 3)
 
+                // Fetch the next entry first before modifying current entry
+                val vbmeta = entry
+                entry = tarIn.nextEntry
+
                 // Update entry with new information
-                entry.name = name
-                entry.size = rawData.size.toLong()
+                vbmeta.name = name
+                vbmeta.size = rawData.size.toLong()
 
                 // Write output
-                tarOut.putArchiveEntry(entry)
+                tarOut.putArchiveEntry(vbmeta)
                 tarOut.write(rawData)
                 tarOut.closeArchiveEntry()
+                continue
             } else if (entry.name.contains("userdata.img")) {
                 console.add("-- Skipping  : ${entry.name}")
-                continue
             } else {
                 console.add("-- Copying   : ${entry.name}")
                 tarOut.putArchiveEntry(entry)
                 tarIn.copyAll(tarOut, bufferSize = 1024 * 1024)
                 tarOut.closeArchiveEntry()
             }
+            entry = tarIn.nextEntry ?: break
         }
 
         // Patch priority: recovery > init_boot > boot