[Bug sanitizer/64741] New: Incorrect size of UBSan type descriptors

[Bug sanitizer/64741] New: Incorrect size of UBSan type descriptors

[y.gribov at samsung dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64741

            Bug ID: 64741
           Summary: Incorrect size of UBSan type descriptors
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: sanitizer
          Assignee: unassigned at gcc dot gnu.org
          Reporter: y.gribov at samsung dot com
                CC: dodji at gcc dot gnu.org, dvyukov at gcc dot gnu.org,
                    jakub at gcc dot gnu.org, kcc at gcc dot gnu.org,
                    ryabinin.a.a at gmail dot com

Created attachment 34540
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=34540&action=edit
Proposed patch

UBSan uses incomplete type for all UBSan type descriptors:
 struct {
   short __typekind;
   short __typeinfo;
   char __typename[];
 };
and this causes DECL_SIZE to return invalid (too short) values for generated
globals. This later causes ASan to report invalid (again, too short) size to
__asan_register_globals when UBSan is enabled together with ASan.

This may not be a problem for userspace (because only libubsan accesses these
descriptors and it's not sanitized) but causes false positives for kernel
(https://lkml.org/lkml/2015/1/22/670).

I attach a silly fix - if it looks more or less fine, I'll do the regtesting
and fw to gcc-patches.

[Bug sanitizer/64741] Incorrect size of UBSan type descriptors

[y.gribov at samsung dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64741

--- Comment #1 from Yury Gribov <y.gribov at samsung dot com> ---
*** Bug 64742 has been marked as a duplicate of this bug. ***

[Bug sanitizer/64741] Incorrect size of UBSan type descriptors

[ygribov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64741

--- Comment #3 from ygribov at gcc dot gnu.org ---
Author: ygribov
Date: Tue Jan 27 09:58:00 2015
New Revision: 220159

URL: https://gcc.gnu.org/viewcvs?rev=220159&root=gcc&view=rev
Log:
2015-01-27  Jakub Jelinek  <jakub@redhat.com>
        Yury Gribov  <y.gribov@samsung.com>

    PR ubsan/64741
    * ubsan.c (ubsan_source_location): Refactor code.
    (ubsan_type_descriptor): Update type size. Refactor code.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/ubsan.c

[Bug sanitizer/64741] Incorrect size of UBSan type descriptors

[y.gribov at samsung dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64741

Yury Gribov <y.gribov at samsung dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |FIXED

--- Comment #4 from Yury Gribov <y.gribov at samsung dot com> ---
.