Re: Memory protection between compilation units?

From	wij <wyniijj5@gmail.com>
Newsgroups	comp.lang.c
Subject	Re: Memory protection between compilation units?
Date	2025-06-14 02:10 +0800
Organization	A noiseless patient Spider
Message-ID	<3de345c2bcf32d122addc3011bc6bdae15fa5a9c.camel@gmail.com> (permalink)
References	<20250611153239.6bc43323@mateusz> <20250612102857.1632c026@mateusz> <20250612114200.143@kylheku.com> <102gjib$39la2$1@dont-email.me> <20250613141420.25d81b43@mateusz>

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On Fri, 2025-06-13 at 14:14 +0200, Mateusz Viste wrote:
> On Fri, 13 Jun 2025 09:21 pozz wrote:
> 
> > However this strategy assumes you already know there's some
> > instruction that write to the array at an out-of-bound position.
> 
> Yes, though I see Kaz's idea is to proactively protect all memory used
> by the program. It's an interesting concept, though not particularly
> practical.
> 
> > I think the situation of the original post is different. His program 
> > crashed infrequently, very infrequently, and he didn't know anything 
> > about the cause. I think it was a very big effort to link the crash
> > to the array (in another source module) and to the out-of-bound
> > access of the array.
> 
> You are spot on indeed. Huge program with lots of modules, processing
> millions of data entries every minute. Realizing that the issue was an
> out of bounds situation was challenging because the symptoms were in a
> totally different part of the program. Very confusing.
> 
> Hence why I was wondering if there is any way to make invalid memory
> accesses *within the same program* generate a segfault, so next time I
> have to deal with such self-sabotaging program I know at least which
> module (compilation unit) to look at. Since then I learned that:
> - There is no readily available mechanism for this today on x86

There will never be a cure for what you are looking for a 'auto range check'
Manually coding for out-of-range is the way to go.

> - CHERI shows great promise, possibly in the coming years
> - mprotect() can offer some degree of protection but must be used
>   carefully, as it primarily safeguards against writes in general rather
>   than restricting which parts of the code can access memory
> 
> Mateusz

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Memory protection between compilation units? Mateusz Viste <mateusz@x.invalid> - 2025-06-11 15:32 +0200
  Re: Memory protection between compilation units? Josef Möllers <josef@invalid.invalid> - 2025-06-11 16:06 +0200
    Re: Memory protection between compilation units? scott@slp53.sl.home (Scott Lurndal) - 2025-06-11 14:32 +0000
      Re: Memory protection between compilation units? Michael S <already5chosen@yahoo.com> - 2025-06-12 20:01 +0300
        Re: Memory protection between compilation units? Mateusz Viste <mateusz@x.invalid> - 2025-06-13 09:13 +0200
      Re: Memory protection between compilation units? Richard Heathfield <rjh@cpax.org.uk> - 2025-06-12 19:15 +0100
        Re: Memory protection between compilation units? Rosario19 <Ros@invalid.invalid> - 2025-06-16 18:14 +0200
          Re: Memory protection between compilation units? Richard Heathfield <rjh@cpax.org.uk> - 2025-06-16 17:53 +0100
  Re: Memory protection between compilation units? Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2025-06-11 14:30 +0000
  Re: Memory protection between compilation units? David Brown <david.brown@hesbynett.no> - 2025-06-11 17:14 +0200
    Re: Memory protection between compilation units? Mateusz Viste <mateusz@x.invalid> - 2025-06-12 14:31 +0200
      Re: Memory protection between compilation units? David Brown <david.brown@hesbynett.no> - 2025-06-12 15:29 +0200
        Re: Memory protection between compilation units? scott@slp53.sl.home (Scott Lurndal) - 2025-06-12 14:27 +0000
  Re: Memory protection between compilation units? Opus <ifonly@youknew.org> - 2025-06-11 17:19 +0200
    Re: Memory protection between compilation units? wij <wyniijj5@gmail.com> - 2025-06-11 23:38 +0800
    Re: Memory protection between compilation units? Mateusz Viste <mateusz@x.invalid> - 2025-06-12 14:41 +0200
      Re: Memory protection between compilation units? scott@slp53.sl.home (Scott Lurndal) - 2025-06-12 13:21 +0000
  Re: Memory protection between compilation units? Kaz Kylheku <643-408-1753@kylheku.com> - 2025-06-11 15:36 +0000
  Re: Memory protection between compilation units? Mateusz Viste <mateusz@x.invalid> - 2025-06-12 10:28 +0200
    Re: Memory protection between compilation units? scott@slp53.sl.home (Scott Lurndal) - 2025-06-12 13:18 +0000
    Re: Memory protection between compilation units? Kaz Kylheku <643-408-1753@kylheku.com> - 2025-06-12 18:59 +0000
      Re: Memory protection between compilation units? Mateusz Viste <mateusz@x.invalid> - 2025-06-13 08:42 +0200
        Re: Memory protection between compilation units? Kaz Kylheku <643-408-1753@kylheku.com> - 2025-06-13 16:17 +0000
      Re: Memory protection between compilation units? pozz <pozzugno@gmail.com> - 2025-06-13 09:21 +0200
        Re: Memory protection between compilation units? Mateusz Viste <mateusz@x.invalid> - 2025-06-13 14:14 +0200
          Re: Memory protection between compilation units? Michael S <already5chosen@yahoo.com> - 2025-06-13 16:56 +0300
            Re: Memory protection between compilation units? Richard Heathfield <rjh@cpax.org.uk> - 2025-06-13 15:43 +0100
              Re: Memory protection between compilation units? Michael S <already5chosen@yahoo.com> - 2025-06-14 22:07 +0300
            Re: Memory protection between compilation units? Kaz Kylheku <643-408-1753@kylheku.com> - 2025-06-13 17:14 +0000
            Re: Memory protection between compilation units? Mateusz Viste <mateusz@not.gonna.tell> - 2025-06-14 21:37 +0000
              Re: Memory protection between compilation units? antispam@fricas.org (Waldek Hebisch) - 2025-06-15 13:57 +0000
                Re: Memory protection between compilation units? Mateusz Viste <mateusz@not.gonna.tell> - 2025-06-15 20:27 +0000
                Re: Memory protection between compilation units? antispam@fricas.org (Waldek Hebisch) - 2025-06-15 23:50 +0000
                Re: Memory protection between compilation units? Kaz Kylheku <643-408-1753@kylheku.com> - 2025-06-16 01:01 +0000
                Re: Memory protection between compilation units? antispam@fricas.org (Waldek Hebisch) - 2025-06-16 10:00 +0000
                Re: Memory protection between compilation units? James Kuyper <jameskuyper@alumni.caltech.edu> - 2025-06-16 06:12 -0400
                Re: Memory protection between compilation units? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2025-06-16 06:10 -0700
                Re: Memory protection between compilation units? antispam@fricas.org (Waldek Hebisch) - 2025-06-16 16:47 +0000
          Re: Memory protection between compilation units? Kaz Kylheku <643-408-1753@kylheku.com> - 2025-06-13 16:23 +0000
          Re: Memory protection between compilation units? wij <wyniijj5@gmail.com> - 2025-06-14 02:10 +0800
  Re: Memory protection between compilation units? Mikko <mikko.levanto@iki.fi> - 2025-06-12 11:40 +0300
    Re: Memory protection between compilation units? Mateusz Viste <mateusz@x.invalid> - 2025-06-12 11:05 +0200
  Re: Memory protection between compilation units? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2025-06-12 06:05 -0700
    Re: Memory protection between compilation units? Bonita Montero <Bonita.Montero@gmail.com> - 2025-06-13 08:03 +0200
      Re: Memory protection between compilation units? wij <wyniijj5@gmail.com> - 2025-06-14 02:16 +0800
        Re: Memory protection between compilation units? Bonita Montero <Bonita.Montero@gmail.com> - 2025-06-13 20:43 +0200
        Re: Memory protection between compilation units? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-06-13 12:32 -0700
          Re: Memory protection between compilation units? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2025-06-13 15:48 -0700
    Re: Memory protection between compilation units? Mateusz Viste <mateusz@x.invalid> - 2025-06-13 08:59 +0200
      Re: Memory protection between compilation units? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2025-06-13 16:31 -0700
        Re: Memory protection between compilation units? Mateusz Viste <mateusz@not.gonna.tell> - 2025-06-14 22:22 +0000
          Re: Memory protection between compilation units? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2025-07-01 09:54 -0700
  Re: Memory protection between compilation units? Bonita Montero <Bonita.Montero@gmail.com> - 2025-06-13 08:00 +0200
    Re: Memory protection between compilation units? Mateusz Viste <mateusz@x.invalid> - 2025-06-13 08:47 +0200
      Re: Memory protection between compilation units? Kaz Kylheku <643-408-1753@kylheku.com> - 2025-06-13 16:19 +0000
  Re: Memory protection between compilation units? Louis Krupp <lkrupp@invalid.pssw.com.invalid> - 2025-06-16 06:29 -0600
    Re: Memory protection between compilation units? Mateusz Viste <mateusz@x.invalid> - 2025-06-16 15:01 +0200
  Re: Memory protection between compilation units? olcott <polcott333@gmail.com> - 2025-06-21 15:49 -0500

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