[hwasan, asan] Intercept vfork.

Summary:
Intercept vfork on arm, aarch64, i386 and x86_64.

Reviewers: pcc, vitalybuka

Subscribers: kubamracek, mgorny, javed.absar, krytarowski, kristof.beyls, #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D58533

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@355030 91177308-0d34-0410-b5e6-96231b3b80d8

6 files changed, 50 insertions, 1 deletions

diff --git a/lib/hwasan/CMakeLists.txt b/lib/hwasan/CMakeLists.txt
index 832335825..1eb16e7e5 100644
--- a/lib/hwasan/CMakeLists.txt
+++ b/lib/hwasan/CMakeLists.txt
@@ -6,6 +6,7 @@ set(HWASAN_RTL_SOURCES
   hwasan_allocator.cpp
   hwasan_dynamic_shadow.cpp
   hwasan_interceptors.cpp
+  hwasan_interceptors_vfork.S
   hwasan_linux.cpp
   hwasan_memintrinsics.cpp
   hwasan_poisoning.cpp
diff --git a/lib/hwasan/hwasan.cpp b/lib/hwasan/hwasan.cpp
index 9978ecef4..03aa6c180 100644
--- a/lib/hwasan/hwasan.cpp
+++ b/lib/hwasan/hwasan.cpp
@@ -480,6 +480,30 @@ void __hwasan_handle_longjmp(const void *sp_dst) {
   TagMemory(sp, dst - sp, 0);
 }
 
+void __hwasan_handle_vfork(const void *sp_dst) {
+  uptr sp = (uptr)sp_dst;
+  Thread *t = GetCurrentThread();
+  CHECK(t);
+  uptr top = t->stack_top();
+  uptr bottom = t->stack_bottom();
+  static const uptr kMaxExpectedCleanupSize = 64 << 20;  // 64M
+  if (top == 0 || bottom == 0 || sp < bottom || sp >= top ||
+      sp - bottom > kMaxExpectedCleanupSize) {
+    Report(
+        "WARNING: HWASan is ignoring requested __hwasan_handle_vfork: "
+        "stack top: %zx; current %zx; bottom: %zx \n"
+        "False positive error reports may follow\n",
+        top, sp, bottom);
+    return;
+  }
+  TagMemory(bottom, sp - bottom, 0);
+}
+
+extern "C" void *__hwasan_extra_spill_area() {
+  Thread *t = GetCurrentThread();
+  return &t->vfork_spill();
+}
+
 void __hwasan_print_memory_usage() {
   InternalScopedString s(kMemoryUsageBufferSize);
   HwasanFormatMemoryUsage(s);
diff --git a/lib/hwasan/hwasan_interceptors.cpp b/lib/hwasan/hwasan_interceptors.cpp
index 3b087e157..326309751 100644
--- a/lib/hwasan/hwasan_interceptors.cpp
+++ b/lib/hwasan/hwasan_interceptors.cpp
@@ -227,6 +227,11 @@ INTERCEPTOR(int, pthread_create, void *th, void *attr,
 }
 #endif
 
+#if HWASAN_WITH_INTERCEPTORS
+DEFINE_REAL(int, vfork);
+DECLARE_EXTERN_INTERCEPTOR_AND_WRAPPER(int, vfork);
+#endif
+
 static void BeforeFork() {
   StackDepotLockAll();
 }
@@ -266,9 +271,12 @@ void InitializeInterceptors() {
   INTERCEPT_FUNCTION(fork);
 
 #if HWASAN_WITH_INTERCEPTORS
+#if defined(__linux__)
+  INTERCEPT_FUNCTION(vfork);
+#endif  // __linux__
 #if !defined(__aarch64__)
   INTERCEPT_FUNCTION(pthread_create);
-#endif
+#endif  // __aarch64__
   INTERCEPT_FUNCTION(realloc);
   INTERCEPT_FUNCTION(free);
 #endif
diff --git a/lib/hwasan/hwasan_interceptors_vfork.S b/lib/hwasan/hwasan_interceptors_vfork.S
new file mode 100644
index 000000000..a980fbd01
--- /dev/null
+++ b/lib/hwasan/hwasan_interceptors_vfork.S
@@ -0,0 +1,10 @@
+#include "sanitizer_common/sanitizer_asm.h"
+
+#if defined(__linux__)
+#define COMMON_INTERCEPTOR_SPILL_AREA __hwasan_extra_spill_area
+#define COMMON_INTERCEPTOR_HANDLE_VFORK __hwasan_handle_vfork
+#include "sanitizer_common/sanitizer_common_interceptors_vfork_aarch64.inc.S"
+#include "sanitizer_common/sanitizer_common_interceptors_vfork_x86_64.inc.S"
+#endif
+
+NO_EXEC_STACK_DIRECTIVE
diff --git a/lib/hwasan/hwasan_interface_internal.h b/lib/hwasan/hwasan_interface_internal.h
index c2ae66653..315b0daef 100644
--- a/lib/hwasan/hwasan_interface_internal.h
+++ b/lib/hwasan/hwasan_interface_internal.h
@@ -117,6 +117,9 @@ SANITIZER_INTERFACE_ATTRIBUTE
 void __hwasan_handle_longjmp(const void *sp_dst);
 
 SANITIZER_INTERFACE_ATTRIBUTE
+void __hwasan_handle_vfork(const void *sp_dst);
+
+SANITIZER_INTERFACE_ATTRIBUTE
 u16 __sanitizer_unaligned_load16(const uu16 *p);
 
 SANITIZER_INTERFACE_ATTRIBUTE
diff --git a/lib/hwasan/hwasan_thread.h b/lib/hwasan/hwasan_thread.h
index 9c45adec1..6fa592bfa 100644
--- a/lib/hwasan/hwasan_thread.h
+++ b/lib/hwasan/hwasan_thread.h
@@ -67,11 +67,14 @@ class Thread {
     Print("Thread: ");
   }
 
+  uptr &vfork_spill() { return vfork_spill_; }
+
  private:
   // NOTE: There is no Thread constructor. It is allocated
   // via mmap() and *must* be valid in zero-initialized state.
   void ClearShadowForThreadStackAndTLS();
   void Print(const char *prefix);
+  uptr vfork_spill_;
   uptr stack_top_;
   uptr stack_bottom_;
   uptr tls_begin_;