Re: [PATCH][PR sanitizer/78651] Incorrect exception handling when catch clause uses local class and PIC and sanitizer are active

[Maxim Ostapenko]

On 03/19/2018 06:55 PM, Jakub Jelinek wrote:

On Mon, Mar 19, 2018 at 06:44:39PM +0300, Maxim Ostapenko wrote:

as noted in bugzilla, ASan inserts redzones for  `.LDFCM*' variables and
breaks internal ABI between GCC and libstdc++ because libstdc++ tries to
obtain a pointer to `typeinfo for (anonymous namespace)::SomeRandomType'
from a constant offset from `.LDFCM*' labels and hits these redzones. This
can be trivially fixed by not sanitizing `.LDFCM*' variables (and other
debug variables) at all.

I don't like very much adding an extra argument for such so frequently used
function to handle a corner case.
Wouldn't just:
   /* Don't instrument this decl with -fsanitize=*address.  */
   unsigned int save_flag_sanitize = flag_sanitize;
   flag_sanitize &= ~(SANITIZE_ADDRESS | SANITIZE_USER_ADDRESS
                     | SANITIZE_KERNEL_ADDRESS);
   assemble_variable (decl, 1, 1, 1);
   flag_sanitize = save_flag_sanitize;
DTRT?

Yes, it works, attaching the patch.

-Maxim

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index b5b5559..356e68c 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2018-03-19  Maxim Ostapenko  <m.ostape...@samsung.com>
+
+	PR sanitizer/78651
+	* dwarf2asm.c (dw2_output_indirect_constant_1): Disable ASan before
+	calling assemble_variable.
+
 2018-03-19  Richard Biener  <rguent...@suse.de>
 
 	PR tree-optimization/84929
diff --git a/gcc/dwarf2asm.c b/gcc/dwarf2asm.c
index e9b18b8..065406b 100644
--- a/gcc/dwarf2asm.c
+++ b/gcc/dwarf2asm.c
@@ -967,7 +967,11 @@ dw2_output_indirect_constant_1 (const char *sym, tree id)
     }
 
   sym_ref = gen_rtx_SYMBOL_REF (Pmode, sym);
+  unsigned int save_flag_sanitize = flag_sanitize;
+  flag_sanitize &= ~(SANITIZE_ADDRESS | SANITIZE_USER_ADDRESS
+		     | SANITIZE_KERNEL_ADDRESS);
   assemble_variable (decl, 1, 1, 1);
+  flag_sanitize = save_flag_sanitize;
   assemble_integer (sym_ref, POINTER_SIZE_UNITS, POINTER_SIZE, 1);
 
   return 0;
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 868d8e8..6ff9217 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2018-03-19  Maxim Ostapenko  <m.ostape...@samsung.com>
+
+	PR sanitizer/78651
+	* g++.dg/asan/pr78651.C: New test.
+
 2018-03-19  Richard Biener  <rguent...@suse.de>
 
 	PR tree-optimization/84929
diff --git a/gcc/testsuite/g++.dg/asan/pr78651.C b/gcc/testsuite/g++.dg/asan/pr78651.C
new file mode 100644
index 0000000..3f14be7
--- /dev/null
+++ b/gcc/testsuite/g++.dg/asan/pr78651.C
@@ -0,0 +1,24 @@
+// { dg-do run { target fpic } }
+
+struct A { };
+
+namespace {
+
+void thisThrows () {
+  throw A();
+}
+
+struct SomeRandomType {};
+}
+
+int main() {
+  try {
+    thisThrows();
+  }
+  catch (SomeRandomType) {
+    throw;
+  }
+  catch (A) {
+  }
+  return 0;
+}