From 4c3c526e54e4ae1fd94480c0c013fb5e6377e3f6 Mon Sep 17 00:00:00 2001
From: Florian Mayer <fmayer@google.com>
Date: Wed, 14 Sep 2022 16:02:11 -0700
Subject: [PATCH] [MTE] Reset MTE state for userdata wipe in fastbootd

Test: $ adb shell su root [...]/mtectrl memtag,memtag-kernel default
      $ adb shell 'su root dd bs=1 skip=32832 if=/dev/block/bootdevice/by-name/misc count=15 | xxd'
      00000000: 015a fefe 5a05 [...]
      $ adb reboot fastboot
      $ fastboot -w
      $ fastboot reboot
      $ adb shell 'su root dd bs=1 skip=32832 if=/dev/block/bootdevice/by-name/misc count=15 | xxd'
      00000000: 0000 0000 0000 [...]

Bug: 245596152
Change-Id: I5e2d4584776ab1685bdf37124e32dcb827eaf05a
---
 fastboot/device/commands.cpp | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/fastboot/device/commands.cpp b/fastboot/device/commands.cpp
index 823783eb2..3799d1fe1 100644
--- a/fastboot/device/commands.cpp
+++ b/fastboot/device/commands.cpp
@@ -40,6 +40,8 @@
 #include <storage_literals/storage_literals.h>
 #include <uuid/uuid.h>
 
+#include <bootloader_message/bootloader_message.h>
+
 #include "BootControlClient.h"
 #include "constants.h"
 #include "fastboot_device.h"
@@ -154,6 +156,14 @@ static bool GetVarAll(FastbootDevice* device) {
     return true;
 }
 
+static void PostWipeData() {
+    std::string err;
+    // Reset mte state of device.
+    if (!WriteMiscMemtagMessage({}, &err)) {
+        LOG(ERROR) << "Failed to reset MTE state: " << err;
+    }
+}
+
 const std::unordered_map<std::string, std::function<bool(FastbootDevice*)>> kSpecialVars = {
         {"all", GetVarAll},
         {"dmesg", GetDmesg},
@@ -232,6 +242,7 @@ bool EraseHandler(FastbootDevice* device, const std::vector<std::string>& args)
         //Perform oem PostWipeData if Android userdata partition has been erased
         bool support_oem_postwipedata = false;
         if (partition_name == "userdata") {
+            PostWipeData();
             support_oem_postwipedata = OemPostWipeData(device);
         }
 
@@ -610,6 +621,10 @@ bool FlashHandler(FastbootDevice* device, const std::vector<std::string>& args)
     if (ret < 0) {
         return device->WriteStatus(FastbootResult::FAIL, strerror(-ret));
     }
+    if (partition_name == "userdata") {
+        PostWipeData();
+    }
+
     return device->WriteStatus(FastbootResult::OKAY, "Flashing succeeded");
 }