[Octave-bug-tracker] [bug #59094] Possible integer overflow in __ode15__.cc

[Markus Mützel]

URL:
  <https://savannah.gnu.org/bugs/?59094>

                 Summary: Possible integer overflow in __ode15__.cc
                 Project: GNU Octave
            Submitted by: mmuetzel
            Submitted on: Thu 10 Sep 2020 05:40:06 PM CEST
                Category: Interpreter
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Segfault, Bus Error, etc.
                  Status: None
             Assigned to: None
         Originator Name: 
        Originator Email: 
             Open/Closed: Open
                 Release: dev
         Discussion Lock: Any
        Operating System: Any

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Details:

It is possible that the multiplication m_num*m_num in the following line in
__ode15__.cc can overflow:

        m_sunJacMatrix = SUNSparseMatrix (m_num, m_num, m_num*m_num,
CSC_MAT);


https://hg.savannah.gnu.org/hgweb/octave/file/0c9a5eae6c27/libinterp/dldfcn/__ode15__.cc#l404

jwe suggested in bug #58795:
> Gnulib has macros for checking whether integer operations overflow, or we
could (conditionally) use things like __builtin_mul_overflow to multiply
dimensions and check for overflow.
> I recently noticed that one of the Octave dependencies (maybe it was
Sundials?) was using the portable snippets library for this job.  Perhaps we
could use that or at least borrow ideas from it.  See, for example, 
https://github.com/nemequ/portable-snippets/tree/master/safe-math
> I hope we can refactor so that we limit the number of places where checks
like this are needed.

The gnulib macros are probably the ones in "intprops.h":
https://git.savannah.gnu.org/gitweb/?p=gnulib.git;a=blob;f=lib/intprops.h;h=df66a3877abbe9e563e2b285297e2702c8106adc;hb=HEAD

IIUC, we try to avoid including gnulib headers directly. Instead we have
wrappers for the functions we want to use.
I don't know how to do something similar with these macros.
Is it ok to include that header directly?





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