From 0af6e5facdcc534e097bbe8f565ad827f159f604 Mon Sep 17 00:00:00 2001
From: Evgeniy Stepanov <eugeni.stepanov@gmail.com>
Date: Wed, 12 Dec 2018 22:10:52 +0000
Subject: [PATCH] [hwasan] Verify Android TLS slot at startup.

Summary:
Add a check that TLS_SLOT_TSAN / TLS_SLOT_SANITIZER, whichever
android_get_tls_slot is using, is not conflicting with
TLS_SLOT_DLERROR.

Reviewers: rprichard, vitalybuka

Subscribers: srhines, kubamracek, llvm-commits

Differential Revision: https://reviews.llvm.org/D55587

llvm-svn: 348979
---
 compiler-rt/lib/hwasan/hwasan.cc       |  2 ++
 compiler-rt/lib/hwasan/hwasan.h        |  2 ++
 compiler-rt/lib/hwasan/hwasan_linux.cc | 17 +++++++++++++++++
 3 files changed, 21 insertions(+)

diff --git a/compiler-rt/lib/hwasan/hwasan.cc b/compiler-rt/lib/hwasan/hwasan.cc
index 7a96bb2..da95891 100644
--- a/compiler-rt/lib/hwasan/hwasan.cc
+++ b/compiler-rt/lib/hwasan/hwasan.cc
@@ -283,6 +283,8 @@ void __hwasan_init() {
 
   __sanitizer_set_report_path(common_flags()->log_path);
 
+  AndroidTestTlsSlot();
+
   DisableCoreDumperIfNecessary();
 
   __hwasan_shadow_init();
diff --git a/compiler-rt/lib/hwasan/hwasan.h b/compiler-rt/lib/hwasan/hwasan.h
index b33ce83..64b1f1a 100644
--- a/compiler-rt/lib/hwasan/hwasan.h
+++ b/compiler-rt/lib/hwasan/hwasan.h
@@ -154,6 +154,8 @@ void UpdateMemoryUsage();
 
 void AppendToErrorMessageBuffer(const char *buffer);
 
+void AndroidTestTlsSlot();
+
 }  // namespace __hwasan
 
 #define HWASAN_MALLOC_HOOK(ptr, size)       \
diff --git a/compiler-rt/lib/hwasan/hwasan_linux.cc b/compiler-rt/lib/hwasan/hwasan_linux.cc
index 750d11d..af9378c 100644
--- a/compiler-rt/lib/hwasan/hwasan_linux.cc
+++ b/compiler-rt/lib/hwasan/hwasan_linux.cc
@@ -24,6 +24,7 @@
 #include "hwasan_thread.h"
 #include "hwasan_thread_list.h"
 
+#include <dlfcn.h>
 #include <elf.h>
 #include <link.h>
 #include <pthread.h>
@@ -283,6 +284,22 @@ uptr *GetCurrentThreadLongPtr() {
 }
 #endif
 
+#if SANITIZER_ANDROID
+void AndroidTestTlsSlot() {
+  uptr kMagicValue = 0x010203040A0B0C0D;
+  *(uptr *)get_android_tls_ptr() = kMagicValue;
+  dlerror();
+  if (*(uptr *)get_android_tls_ptr() != kMagicValue) {
+    Printf(
+        "ERROR: Incompatible version of Android: TLS_SLOT_SANITIZER(6) is used "
+        "for dlerror().\n");
+    Die();
+  }
+}
+#else
+void AndroidTestTlsSlot() {}
+#endif
+
 Thread *GetCurrentThread() {
   auto *R = (StackAllocationsRingBuffer*)GetCurrentThreadLongPtr();
   return hwasanThreadList().GetThreadByBufferAddress((uptr)(R->Next()));
-- 
2.7.4