Re: Type-safety and C++, was: Re: Dimension of a matrix

From	Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP>
Newsgroups	comp.arch.embedded
Subject	Re: Type-safety and C++, was: Re: Dimension of a matrix
Date	2017-03-30 00:23 +0000
Organization	A noiseless patient Spider
Message-ID	<obhj60$a4n$3@dont-email.me> (permalink)
References	(11 earlier) <q7ydnQkIucY73kTFnZ2dnUU7-fWdnZ2d@giganews.com> <87shlxuclb.fsf@nightsong.com> <obd2p6$c2r$1@dont-email.me> <obeuni$kkv$1@dont-email.me> <obfr85$g0i$1@dont-email.me>

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On 2017-03-29, David Brown <david.brown@hesbynett.no> wrote:
>
> There are some kinds of defects that can be avoided by good design.
> Some kinds can be spotted by static error checking at compile time.  And
> some kinds can be best spotted using tests.
>
> Array overruns are best avoided by good programming practice - you know
> exactly what size your array is when you use it.  You don't make
> assumptions - make sure you /know/.  And they are usually very hard to
> find by tests - the effect of an array overrun is typically "something
> odd is happening" because you have written to a different memory object
> unexpectedly.
>
> You cannot sensibly use run-time checks of array sizes, except
> occasionally during development.  You can only check the array bounds on
> access if you know the bounds - and if you know the bounds during the
> access, then the code that makes the accesses already knows these bounds
> and should not attempt such accesses.  At best, you might spot
> typographical errors - using "sizeOfInBuffer" when you meant
> "sizeOfOutBuffer".
>

If you have to do those checks manually, then some developers might
not include them or may remove them when building the production
release.

Leaving those checks (either manual or compiler generated) in the
production build may stop your code from turning into a CVE if an
attacker can influence your program logic via an external mechanism
in a way that you never thought to test for during development.

IOW, I do believe that run-time checks have a vital place, even in
production use, especially in today's heavily interconnected world.

Simon.

-- 
Simon Clubley, clubley@remove_me.eisner.decus.org-Earth.UFP
Microsoft: Bringing you 1980s technology to a 21st century world

Thread

Dimension of a matrix Tim Wescott <seemywebsite@myfooter.really> - 2017-03-23 18:17 -0500
  Re: Dimension of a matrix Paul Rubin <no.email@nospam.invalid> - 2017-03-23 23:21 -0700
    Re: Dimension of a matrix David Brown <david.brown@hesbynett.no> - 2017-03-24 09:18 +0100
      Type-safety and C++, was: Re: Dimension of a matrix Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP> - 2017-03-24 18:24 +0000
        Re: Type-safety and C++, was: Re: Dimension of a matrix Tim Wescott <tim@seemywebsite.com> - 2017-03-24 19:32 -0500
          Re: Type-safety and C++, was: Re: Dimension of a matrix Stefan Reuther <stefan.news@arcor.de> - 2017-03-25 09:59 +0100
          Re: Type-safety and C++, was: Re: Dimension of a matrix Les Cargill <lcargill99@comcast.com> - 2017-03-25 13:08 -0500
        Re: Type-safety and C++, was: Re: Dimension of a matrix David Brown <david.brown@hesbynett.no> - 2017-03-25 01:57 +0100
          Re: Type-safety and C++, was: Re: Dimension of a matrix Clifford Heath <no.spam@please.net> - 2017-03-25 18:34 +1100
            Re: Type-safety and C++, was: Re: Dimension of a matrix Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP> - 2017-03-26 23:53 +0000
              Re: Type-safety and C++, was: Re: Dimension of a matrix David Brown <david.brown@hesbynett.no> - 2017-03-27 09:51 +0200
                Re: Type-safety and C++, was: Re: Dimension of a matrix Clifford Heath <no.spam@please.net> - 2017-03-27 20:19 +1100
                Re: Type-safety and C++, was: Re: Dimension of a matrix David Brown <david.brown@hesbynett.no> - 2017-03-27 12:17 +0200
          Re: Type-safety and C++, was: Re: Dimension of a matrix Paul Rubin <no.email@nospam.invalid> - 2017-03-25 09:20 -0700
        Re: Type-safety and C++, was: Re: Dimension of a matrix George Neuner <gneuner2@comcast.net> - 2017-03-24 23:14 -0400
          Re: Type-safety and C++, was: Re: Dimension of a matrix Tim Wescott <tim@seemywebsite.com> - 2017-03-25 11:07 -0500
            Re: Type-safety and C++, was: Re: Dimension of a matrix George Neuner <gneuner2@comcast.net> - 2017-03-26 05:45 -0400
              Re: Type-safety and C++, was: Re: Dimension of a matrix Wouter van Ooijen <wouter@voti.nl> - 2017-03-26 13:14 +0200
                Re: Type-safety and C++, was: Re: Dimension of a matrix Paul Rubin <no.email@nospam.invalid> - 2017-03-26 11:08 -0700
                Re: Type-safety and C++, was: Re: Dimension of a matrix Wouter van Ooijen <wouter@voti.nl> - 2017-03-26 20:24 +0200
              Re: Type-safety and C++, was: Re: Dimension of a matrix Tim Wescott <tim@seemywebsite.com> - 2017-03-26 15:16 -0500
                Re: Type-safety and C++, was: Re: Dimension of a matrix Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP> - 2017-03-27 00:09 +0000
                Re: Type-safety and C++, was: Re: Dimension of a matrix Tim Wescott <seemywebsite@myfooter.really> - 2017-03-26 19:43 -0500
                Re: Type-safety and C++, was: Re: Dimension of a matrix Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-03-27 16:57 +0100
                Re: Type-safety and C++, was: Re: Dimension of a matrix Tim Wescott <tim@seemywebsite.com> - 2017-03-27 11:53 -0500
                Re: Type-safety and C++, was: Re: Dimension of a matrix David Brown <david.brown@hesbynett.no> - 2017-03-27 22:04 +0200
                Re: Type-safety and C++, was: Re: Dimension of a matrix Tim Wescott <seemywebsite@myfooter.really> - 2017-03-27 18:32 -0500
                Re: Type-safety and C++, was: Re: Dimension of a matrix Clifford Heath <no.spam@please.net> - 2017-03-28 11:03 +1100
                Re: Type-safety and C++, was: Re: Dimension of a matrix Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-03-27 22:07 +0100
                Re: Type-safety and C++, was: Re: Dimension of a matrix Paul Rubin <no.email@nospam.invalid> - 2017-03-27 23:42 -0700
                Re: Type-safety and C++, was: Re: Dimension of a matrix David Brown <david.brown@hesbynett.no> - 2017-03-28 09:22 +0200
                Re: Type-safety and C++, was: Re: Dimension of a matrix Paul Rubin <no.email@nospam.invalid> - 2017-03-28 00:42 -0700
                Re: Type-safety and C++, was: Re: Dimension of a matrix Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-03-28 09:07 +0100
                Re: Type-safety and C++, was: Re: Dimension of a matrix Les Cargill <lcargill99@comcast.com> - 2017-03-28 19:34 -0500
                Re: Type-safety and C++, was: Re: Dimension of a matrix Tim Wescott <tim@seemywebsite.com> - 2017-03-29 11:39 -0500
                Re: Type-safety and C++, was: Re: Dimension of a matrix Les Cargill <lcargill99@comcast.com> - 2017-03-28 19:29 -0500
                Re: Type-safety and C++, was: Re: Dimension of a matrix David Brown <david.brown@hesbynett.no> - 2017-03-29 10:31 +0200
                Re: Type-safety and C++, was: Re: Dimension of a matrix Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP> - 2017-03-30 00:23 +0000
                Re: Type-safety and C++, was: Re: Dimension of a matrix Les Cargill <lcargill99@comcast.com> - 2017-03-29 19:31 -0500
                Re: Type-safety and C++, was: Re: Dimension of a matrix Phil Martel <pomartel@comcast.net> - 2017-03-30 11:51 -0400
                Re: Type-safety and C++, was: Re: Dimension of a matrix Les Cargill <lcargill99@comcast.com> - 2017-03-30 19:16 -0500
                Re: Type-safety and C++, was: Re: Dimension of a matrix David Brown <david.brown@hesbynett.no> - 2017-03-31 09:21 +0200
                Re: Type-safety and C++, was: Re: Dimension of a matrix Tim Wescott <seemywebsite@myfooter.really> - 2017-03-28 14:19 -0500
    Re: Dimension of a matrix Tim Wescott <tim@seemywebsite.com> - 2017-03-24 11:05 -0500
      Re: Dimension of a matrix David Brown <david.brown@hesbynett.no> - 2017-03-24 17:33 +0100
        Re: Dimension of a matrix Tim Wescott <tim@seemywebsite.com> - 2017-03-24 12:09 -0500
      Re: Dimension of a matrix Les Cargill <lcargill99@comcast.com> - 2017-03-25 13:09 -0500
    Re: Dimension of a matrix Les Cargill <lcargill99@comcast.com> - 2017-03-25 13:05 -0500
  Re: Dimension of a matrix David Brown <david.brown@hesbynett.no> - 2017-03-24 09:20 +0100
    Re: Dimension of a matrix Les Cargill <lcargill99@comcast.com> - 2017-03-25 13:12 -0500
      Re: Dimension of a matrix Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2017-03-25 20:08 +0100
        Re: Dimension of a matrix Les Cargill <lcargill99@comcast.com> - 2017-03-25 15:17 -0500
          Re: Dimension of a matrix David Brown <david.brown@hesbynett.no> - 2017-03-26 17:32 +0200
            Re: Dimension of a matrix Les Cargill <lcargill99@comcast.com> - 2017-03-26 11:55 -0500
              Re: Dimension of a matrix David Brown <david.brown@hesbynett.no> - 2017-03-26 21:23 +0200
                Re: Dimension of a matrix Les Cargill <lcargill99@comcast.com> - 2017-03-29 19:36 -0500
                Re: Dimension of a matrix Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP> - 2017-03-30 00:36 +0000
                Re: Dimension of a matrix Paul Rubin <no.email@nospam.invalid> - 2017-03-29 19:55 -0700
                Re: Dimension of a matrix David Brown <david.brown@hesbynett.no> - 2017-03-30 09:49 +0200
                Re: Dimension of a matrix Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP> - 2017-03-30 18:07 +0000
                Re: Dimension of a matrix David Brown <david.brown@hesbynett.no> - 2017-03-30 09:47 +0200
  Re: Dimension of a matrix Wouter van Ooijen <wouter@voti.nl> - 2017-03-25 19:08 +0100
    Re: Dimension of a matrix Les Cargill <lcargill99@comcast.com> - 2017-03-25 15:21 -0500
      Re: Dimension of a matrix Wouter van Ooijen <wouter@voti.nl> - 2017-03-26 14:43 +0200

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