[Bug sanitizer/98608] New: missing sanitizer detection for arrays with invalid length defind using typeof

[Bug sanitizer/98608] New: missing sanitizer detection for arrays with invalid length defind using typeof

[muecker at gwdg dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98608

            Bug ID: 98608
           Summary: missing sanitizer detection for arrays with invalid
                    length defind using typeof
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: sanitizer
          Assignee: unassigned at gcc dot gnu.org
          Reporter: muecker at gwdg dot de
                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, marxin at gcc dot gnu.org
  Target Milestone: ---

The following invalid code is not detected with -fsanitize=undefined

void f(int n, double (*x)[n])
{
        typeof(*x) y;
//      double y[n];
}

int main()
{
        f(-1, 0);
}

Using the definition without typedef yields:

src/test.c:5:9: runtime error: variable length array bound evaluates to
non-positive value -1

[Bug sanitizer/98608] missing sanitizer detection for arrays with invalid length defind using typeof

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98608

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |NEW
                 CC|                            |mpolacek at gcc dot gnu.org
   Last reconfirmed|                            |2021-01-11

--- Comment #1 from Martin Liška <marxin at gcc dot gnu.org> ---
Confirmed.
@Marek: Can you please take a look?

[Bug sanitizer/98608] missing sanitizer detection for arrays with invalid length defind using typeof

[muecker at gwdg dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98608

--- Comment #2 from Martin Uecker <muecker at gwdg dot de> ---

The problem is actually the missing sanitizer instrumentation of the parameter
type. This is easy to fix, but then I run into the problem that a lot of code
has n == 0 in parameters. Having an option to avoid the instrumentation
(PR98609) might help.

[Bug sanitizer/98608] missing sanitizer detection for arrays with invalid length defind using typeof

[muecker at gwdg dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98608

--- Comment #3 from Martin Uecker <muecker at gwdg dot de> ---

PATCH (but unclear about n == 0)
https://gcc.gnu.org/pipermail/gcc-patches/2023-November/634896.html