From e2ed800d622567b35968a27f8784705fb48190f5 Mon Sep 17 00:00:00 2001
From: David Carlier <devnexen@gmail.com>
Date: Thu, 22 Aug 2019 21:36:35 +0000
Subject: [PATCH] [Sanitizer] checks ASLR on FreeBSD

- Especially MemorySanitizer fails if those sysctl configs are enabled.

Reviewers: vitalybuka, emaste, dim

Reviewed By: dim

Differential Revision: https://reviews.llvm.org/D66582

llvm-svn: 369708
---
 compiler-rt/lib/asan/asan_rtl.cpp             |  2 +-
 compiler-rt/lib/msan/msan.cpp                 |  2 +-
 .../lib/sanitizer_common/sanitizer_linux.cpp  | 27 +++++++++++++++++++
 3 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/compiler-rt/lib/asan/asan_rtl.cpp b/compiler-rt/lib/asan/asan_rtl.cpp
index b16ca950518c..f720126098bc 100644
--- a/compiler-rt/lib/asan/asan_rtl.cpp
+++ b/compiler-rt/lib/asan/asan_rtl.cpp
@@ -402,7 +402,6 @@ static void AsanInitInternal() {
   asan_init_is_running = true;
 
   CacheBinaryName();
-  CheckASLR();
 
   // Initialize flags. This must be done early, because most of the
   // initialization steps look at flags().
@@ -450,6 +449,7 @@ static void AsanInitInternal() {
   SetLowLevelAllocateCallback(OnLowLevelAllocate);
 
   InitializeAsanInterceptors();
+  CheckASLR();
 
   // Enable system log ("adb logcat") on Android.
   // Doing this before interceptors are initialized crashes in:
diff --git a/compiler-rt/lib/msan/msan.cpp b/compiler-rt/lib/msan/msan.cpp
index 1bc505e442cc..f5b05c460d8d 100644
--- a/compiler-rt/lib/msan/msan.cpp
+++ b/compiler-rt/lib/msan/msan.cpp
@@ -403,7 +403,6 @@ void __msan_init() {
   AvoidCVE_2016_2143();
 
   CacheBinaryName();
-  CheckASLR();
   InitializeFlags();
 
   // Install tool-specific callbacks in sanitizer_common.
@@ -412,6 +411,7 @@ void __msan_init() {
   __sanitizer_set_report_path(common_flags()->log_path);
 
   InitializeInterceptors();
+  CheckASLR();
   InitTlsSize();
   InstallDeadlySignalHandlers(MsanOnDeadlySignal);
   InstallAtExitHandler(); // Needs __cxa_atexit interceptor.
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp
index 1ed6af33fb8a..01be223d3e0d 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp
@@ -2011,6 +2011,33 @@ void CheckASLR() {
     CHECK_NE(personality(old_personality | ADDR_NO_RANDOMIZE), -1);
     ReExec();
   }
+#elif SANITIZER_FREEBSD
+  int aslr_pie;
+  uptr len = sizeof(aslr_pie);
+#if SANITIZER_WORDSIZE == 64
+  if (UNLIKELY(internal_sysctlbyname("kern.elf64.aslr.pie_enable",
+      &aslr_pie, &len, NULL, 0) == -1)) {
+    // We're making things less 'dramatic' here since
+    // the OID is not necessarily guaranteed to be here
+    // just yet regarding FreeBSD release
+    return;
+  }
+
+  if (aslr_pie > 0) {
+    Printf("This sanitizer is not compatible with enabled ASLR and binaries compiled with PIE\n");
+    Die();
+  }
+#endif
+  // there might be 32 bits compat for 64 bits
+  if (UNLIKELY(internal_sysctlbyname("kern.elf32.aslr.pie_enable",
+      &aslr_pie, &len, NULL, 0) == -1)) {
+    return;
+  }
+
+  if (aslr_pie > 0) {
+    Printf("This sanitizer is not compatible with enabled ASLR and binaries compiled with PIE\n");
+    Die();
+  }
 #else
   // Do nothing
 #endif