Re: [PATCH] Fix PR sanitizer/PR69276

[Martin LiÅka <mliska at suse dot cz>]

On 01/27/2016 01:58 PM, Jakub Jelinek wrote:
> On Wed, Jan 27, 2016 at 01:47:10PM +0100, Martin LiÅka wrote:
>> Following patch was kind of pre-approved by Jakub in:
>> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69276#c4
>>
>> Patch can bootstrap in x86_64-linux-gnu and survives regression tests.
>> I also verified that newly added test-case works with the patch.
>>
>> Ready for trunk?
> 
> Ok, with nits.
> 
>> >From 4e4575cfef5d06d8e8477716ce2f4d7e28ae66f0 Mon Sep 17 00:00:00 2001
>> From: marxin <mliska@suse.cz>
>> Date: Thu, 14 Jan 2016 18:15:04 +0100
>> Subject: [PATCH] Fix PR sanitizer/PR69276
>>
>> gcc/testsuite/ChangeLog:
>>
>> 2016-01-14  Martin Liska  <mliska@suse.cz>
>>
>> 	* g++.dg/asan/pr69276.C: New test.
>>
>> gcc/ChangeLog:
>>
>> 2016-01-14  Martin Liska  <mliska@suse.cz>
>>
>> 	PR sanitizer/PR69276
>> 	* asan.c (has_stmt_been_instrumented_p): Instrument gimple calls
>> 	that are gimple_store_p.
>> 	(maybe_instrument_call): Likewise.
>> ---
>>  gcc/asan.c                          | 21 ++++++++++++++++++++
>>  gcc/testsuite/g++.dg/asan/pr69276.C | 38 +++++++++++++++++++++++++++++++++++++
>>  2 files changed, 59 insertions(+)
>>  create mode 100644 gcc/testsuite/g++.dg/asan/pr69276.C
>>
>> diff --git a/gcc/asan.c b/gcc/asan.c
>> index 2f9f92f..1747e90 100644
>> --- a/gcc/asan.c
>> +++ b/gcc/asan.c
>> @@ -2038,6 +2048,17 @@ maybe_instrument_call (gimple_stmt_iterator *iter)
>>        gimple_set_location (g, gimple_location (stmt));
>>        gsi_insert_before (iter, g, GSI_SAME_STMT);
>>      }
>> +  else if (gimple_store_p (stmt))
> 
> I'd remove the "else " here, I believe if a noreturn call returns aggregate
> the lhs is not removed and the store can still (partially) happen, if it is
> returned by invisible reference.  

Hi Jakub.

Ah, you are right, good nit!

Do you instrument it before the call or
> after btw?  Before the call might be premature, the call might not return
> and not store anything into the result, after the call might be too late
> (store happened already).

The instrumentation is applied before the call. Hope we do not introduce
a new false positives.

Can I apply the v2?

Thanks,
Martin

> 
> 	Jakub
> 

>From d78539fdd0a0d3c3275eb0cdbdd50d7b6ddf9c4c Mon Sep 17 00:00:00 2001
From: marxin <mliska@suse.cz>
Date: Thu, 14 Jan 2016 18:15:04 +0100
Subject: [PATCH] Fix PR sanitizer/PR69276

gcc/testsuite/ChangeLog:

2016-01-14  Martin Liska  <mliska@suse.cz>

	* g++.dg/asan/pr69276.C: New test.

gcc/ChangeLog:

2016-01-14  Martin Liska  <mliska@suse.cz>

	PR sanitizer/PR69276
	* asan.c (has_stmt_been_instrumented_p): Instrument gimple calls
	that are gimple_store_p.
	(maybe_instrument_call): Likewise.
---
 gcc/asan.c                          | 22 +++++++++++++++++++++
 gcc/testsuite/g++.dg/asan/pr69276.C | 38 +++++++++++++++++++++++++++++++++++++
 2 files changed, 60 insertions(+)
 create mode 100644 gcc/testsuite/g++.dg/asan/pr69276.C

diff --git a/gcc/asan.c b/gcc/asan.c
index 2f9f92f..aeb840d 100644
--- a/gcc/asan.c
+++ b/gcc/asan.c
@@ -897,6 +897,16 @@ has_stmt_been_instrumented_p (gimple *stmt)
 	  return true;
 	}
     }
+  else if (is_gimple_call (stmt) && gimple_store_p (stmt))
+    {
+      asan_mem_ref r;
+      asan_mem_ref_init (&r, NULL, 1);
+
+      r.start = gimple_call_lhs (stmt);
+      r.access_size = int_size_in_bytes (TREE_TYPE (r.start));
+      return has_mem_ref_been_instrumented (&r);
+    }
+
   return false;
 }
 
@@ -2038,6 +2048,18 @@ maybe_instrument_call (gimple_stmt_iterator *iter)
       gimple_set_location (g, gimple_location (stmt));
       gsi_insert_before (iter, g, GSI_SAME_STMT);
     }
+
+  if (gimple_store_p (stmt))
+    {
+      tree ref_expr = gimple_call_lhs (stmt);
+      instrument_derefs (iter, ref_expr,
+			 gimple_location (stmt),
+			 /*is_store=*/true);
+
+      gsi_next (iter);
+      return true;
+    }
+
   return false;
 }
 
diff --git a/gcc/testsuite/g++.dg/asan/pr69276.C b/gcc/testsuite/g++.dg/asan/pr69276.C
new file mode 100644
index 0000000..ff43650
--- /dev/null
+++ b/gcc/testsuite/g++.dg/asan/pr69276.C
@@ -0,0 +1,38 @@
+/* { dg-do run } */
+/* { dg-shouldfail "asan" } */
+/* { dg-additional-options "-O0 -fno-lto" } */
+
+#include <stdlib.h>
+
+typedef __SIZE_TYPE__ size_t;
+inline void * operator new (size_t, void *p) { return p; }
+
+
+struct vec
+{
+  int size;
+};
+
+struct vnull
+{
+  operator vec() { return vec(); }
+};
+vnull vNULL;
+
+struct A
+{
+  A(): value2 (vNULL), value3 (vNULL) {}
+  int value;
+  vec value2;
+  vec value3;
+};
+
+int main()
+{
+  int *array = (int *)malloc (sizeof (int) * 1);
+  A *a = new (array) A ();
+  free (array);
+}
+
+/* { dg-output "ERROR: AddressSanitizer: heap-buffer-overflow.*(\n|\r\n|\r)" } */
+/* { dg-output "    #0 0x\[0-9a-f\]+ +in A::A()" } */
-- 
2.7.0