[compiler-rt] r259007 - [cfi] Fix recovery from out-of-bounds vtable error.

[Evgeniy Stepanov via llvm-commits]

Author: eugenis
Date: Wed Jan 27 18:37:54 2016
New Revision: 259007

URL: http://llvm.org/viewvc/llvm-project?rev=259007&view=rev
Log:
[cfi] Fix recovery from out-of-bounds vtable error.

Modified:
    compiler-rt/trunk/lib/cfi/cfi.cc
    compiler-rt/trunk/test/cfi/cross-dso/target_out_of_bounds.cpp

Modified: compiler-rt/trunk/lib/cfi/cfi.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/cfi/cfi.cc?rev=259007&r1=259006&r2=259007&view=diff
==============================================================================
--- compiler-rt/trunk/lib/cfi/cfi.cc (original)
+++ compiler-rt/trunk/lib/cfi/cfi.cc Wed Jan 27 18:37:54 2016
@@ -306,12 +306,14 @@ ALWAYS_INLINE void CfiSlowPathCommon(u64
     // FIXME: call the ubsan handler if DiagData != nullptr?
     VReport(1, "CFI: invalid memory region for a check target: %p\n", Ptr);
 #ifdef CFI_ENABLE_DIAG
-    if (DiagData)
+    if (DiagData) {
       __ubsan_handle_cfi_check_fail(
           reinterpret_cast<__ubsan::CFICheckFailData *>(DiagData),
           reinterpret_cast<uptr>(Ptr));
-    else
+      return;
+    } else {
       Trap();
+    }
 #else
     Trap();
 #endif
@@ -348,7 +350,8 @@ void InitializeFlags() {
 
   SetVerbosity(common_flags()->verbosity);
 
-  if (Verbosity()) ReportUnrecognizedFlags();
+  if (Verbosity())
+    ReportUnrecognizedFlags();
 
   if (common_flags()->help) {
     cfi_parser.PrintFlagDescriptions();

Modified: compiler-rt/trunk/test/cfi/cross-dso/target_out_of_bounds.cpp
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/test/cfi/cross-dso/target_out_of_bounds.cpp?rev=259007&r1=259006&r2=259007&view=diff
==============================================================================
--- compiler-rt/trunk/test/cfi/cross-dso/target_out_of_bounds.cpp (original)
+++ compiler-rt/trunk/test/cfi/cross-dso/target_out_of_bounds.cpp Wed Jan 27 18:37:54 2016
@@ -20,9 +20,13 @@ int main(int argc, char *argv[]) {
   // enough to handle unaddressable vtables. TODO: fix this.
   void *empty = calloc(1, 128);
   uintptr_t v = (uintptr_t)empty + 64;
-  A *volatile p = new A();
-  for (uintptr_t *q = (uintptr_t *)p; q < (uintptr_t *)(p + 1); ++q)
+  char *volatile p = reinterpret_cast<char *>(new A());
+  for (uintptr_t *q = (uintptr_t *)p; q < (uintptr_t *)(p + sizeof(A)); ++q)
     *q = v;
+
+  // CHECK: runtime error: control flow integrity check for type 'A' failed during cast
+  A *volatile pa = reinterpret_cast<A *>(p);
+
   // CHECK: untime error: control flow integrity check for type 'A' failed during virtual call
-  p->f();
+  pa->f();
 }