Reland^2 "[MTE] remap stacks with PROT_MTE when requested by dlopened library"
Also enable stack MTE if main binary links in a library that needs it.
Otherwise the following is possible:
1. a binary doesn't require stack MTE, but links in libraries that use
stg on the stack
2. that binary later dlopens a library that requires stack MTE, and our
logic in dlopen remaps the stacks with MTE
3. the libraries from step 1 now have tagged pointers with missing tags
in memory, so things go wrong
This reverts commit f53e91cc810be2a36377f3b7765f50c89f1f0046.
Reason for revert: Fixed problem detected in b/324568991
Test: atest memtag_stack_dlopen_test with MTE enabled
Test: check crash is gone on fullmte build
Change-Id: I4a93f6814a19683c3ea5fe1e6d455df5459d31e1
diff --git a/tests/mte_utils.h b/tests/mte_utils.h
new file mode 100644
index 0000000..0f18442
--- /dev/null
+++ b/tests/mte_utils.h
@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2024 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.
+ */
+
+#pragma once
+
+#if defined(__BIONIC__) && defined(__aarch64__)
+
+__attribute__((target("mte"))) static bool is_stack_mte_on() {
+ alignas(16) int x = 0;
+ void* p = reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(&x) + (1UL << 57));
+ void* p_cpy = p;
+ __builtin_arm_stg(p);
+ p = __builtin_arm_ldg(p);
+ __builtin_arm_stg(&x);
+ return p == p_cpy;
+}
+
+#endif