Add command line tool to control MTE boot state.

Change-Id: I24271eb642a2a908fe6053a14b48d0780d5ad3a0

4 files changed, 100 insertions, 0 deletions

diff --git a/mtectrl/Android.bp b/mtectrl/Android.bp
new file mode 100644
index 00000000..642f9f4a
--- /dev/null
+++ b/mtectrl/Android.bp
@@ -0,0 +1,23 @@
+// Copyright (C) 2022 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+cc_binary {
+  name: "mtectrl",
+  srcs: ["mtectrl.cc"],
+  shared_libs: [
+    "libbootloader_message",
+    "libbase",
+  ],
+  init_rc: ["mtectrl.rc"],
+}
diff --git a/mtectrl/OWNERS b/mtectrl/OWNERS
new file mode 100644
index 00000000..79625dfb
--- /dev/null
+++ b/mtectrl/OWNERS
@@ -0,0 +1,5 @@
+fmayer@google.com
+
+eugenis@google.com
+mitchp@google.com
+pcc@google.com
diff --git a/mtectrl/mtectrl.cc b/mtectrl/mtectrl.cc
new file mode 100644
index 00000000..0738f9ec
--- /dev/null
+++ b/mtectrl/mtectrl.cc
@@ -0,0 +1,56 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <android-base/logging.h>
+#include <android-base/strings.h>
+#include <bootloader_message/bootloader_message.h>
+
+#include <iostream>
+
+int main(int argc, char** argv) {
+  if (argc != 2) {
+    std::cerr
+        << "Usage: " << argv[0]
+        << " [none|memtag|memtag_once|memtag_kernel|memtag_kernel_once]\n";
+    return 1;
+  }
+  std::string value = argv[1];
+  misc_memtag_message m = {.version = MISC_MEMTAG_MESSAGE_VERSION,
+                           .magic = MISC_MEMTAG_MAGIC_HEADER};
+  for (const auto& field : android::base::Split(value, ",")) {
+    if (field == "memtag") {
+      m.memtag_mode |= MISC_MEMTAG_MODE_MEMTAG;
+    } else if (field == "memtag-once") {
+      m.memtag_mode |= MISC_MEMTAG_MODE_MEMTAG_ONCE;
+    } else if (field == "memtag-kernel") {
+      m.memtag_mode |= MISC_MEMTAG_MODE_MEMTAG_KERNEL;
+    } else if (field == "memtag-kernel-once") {
+      m.memtag_mode |= MISC_MEMTAG_MODE_MEMTAG_KERNEL_ONCE;
+    } else if (field != "none") {
+      LOG(ERROR) << "Unknown value for arm64.memtag.bootctl: " << field;
+      return 1;
+    }
+  }
+  std::string err;
+  if (!WriteMiscMemtagMessage(m, &err)) {
+    LOG(ERROR) << "Failed to apply arm64.memtag.bootctl: " << value << ". "
+               << err;
+    return 1;
+  } else {
+    LOG(INFO) << "Applied arm64.memtag.bootctl: " << value;
+    return 0;
+  }
+}
diff --git a/mtectrl/mtectrl.rc b/mtectrl/mtectrl.rc
new file mode 100644
index 00000000..de042376
--- /dev/null
+++ b/mtectrl/mtectrl.rc
@@ -0,0 +1,16 @@
+# Copyright (C) 2022 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+on property:arm64.memtag.bootctl=*
+  exec -- /system/bin/mtectrl ${arm64.memtag.bootctl}