Re: C is not a low level language

From	Richard Heathfield <rjh@cpax.org.uk>
Newsgroups	comp.lang.c, comp.programming, alt.os.linux.ubuntu, comp.sys.raspberry-pi, alt.comp.os.windows-10, alt.windows7.general
Subject	Re: C is not a low level language
Date	2019-02-24 13:09 +0000
Organization	Fix this later
Message-ID	<q4u52p$k5l$1@dont-email.me> (permalink)
References	(1 earlier) <q4t5ht$ol3$2@toylet.eternal-september.org> <q4t78c$ver$1@toylet.eternal-september.org> <q4t9bu$81p$1@dont-email.me> <q4t9jr$904$1@toylet.eternal-september.org> <q4tjj0$h3k$1@news.albasani.net>

Cross-posted to 6 groups.

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On 24/02/2019 08:11, Martin Gregorie wrote:

<snip>

> There are (relatively) simple ways to write secure code, such as always
> using the 'strn...' functions rather than the older 'str...' equivalents

This is a common misconception. The strn functions are, in some ways, 
even easier to abuse than the str functions.

Hitchens's Razor, right? Okay, my rationale is this: those who think the 
strn functions are somehow "safe" are far more likely to use them 
*instead* of taking trouble to ensure that the right amount of storage 
is allocated. And consider this:

  char s[12];
  strncpy(s, argv[1], 12);

(Heck no, of course I wouldn't do that. But people do, you know.)

The problem here is that if argv[1] is longer than 11 characters, you 
end up with no terminator on the stri... well, it's not a string because 
it doesn't have a terminator!

So much for "safe" functions.

> and *taking the trouble to size storage correctly* that make code a lot
> more bullet-proof.

This, however, is absolutely spot on.

If you don't have enough space for your data, you're going to get the 
wrong answer even if you use strn. If I'm allowed to get the wrong 
answer, I can write code that runs in almost zero time and takes almost 
zero memory.

If you take the trouble to ensure that you have enough space for your 
data, there's nothing wrong with using str.

<snip>

-- 
Richard Heathfield
Email: rjh at cpax dot org dot uk
"Usenet is a strange place" - dmr 29 July 1999
Sig line 4 vacant - apply within

Thread

Re: C is not a low level language "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2019-02-24 12:40 +0800
  Re: C is not a low level language The Natural Philosopher <tnp@invalid.invalid> - 2019-02-24 05:16 +0000
    Re: C is not a low level language "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2019-02-24 13:20 +0800
      Re: C is not a low level language "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2019-02-24 13:24 +0800
      Re: C is not a low level language "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2019-02-24 19:45 +0800
      Re: C is not a low level language Richard Heathfield <rjh@cpax.org.uk> - 2019-02-24 13:09 +0000
        Re: C is not a low level language The Natural Philosopher <tnp@invalid.invalid> - 2019-02-24 14:38 +0000
          Re: C is not a low level language Richard Heathfield <rjh@cpax.org.uk> - 2019-02-24 15:18 +0000
            Re: C is not a low level language "R.Wieser" <address@not.available> - 2019-02-24 17:21 +0100
              Re: C is not a low level language The Natural Philosopher <tnp@invalid.invalid> - 2019-02-24 17:43 +0000
                Re: C is not a low level language "R.Wieser" <address@not.available> - 2019-02-24 20:17 +0100
              Re: C is not a low level language Richard Heathfield <rjh@cpax.org.uk> - 2019-02-24 18:19 +0000
                Re: C is not a low level language "R.Wieser" <address@not.available> - 2019-02-24 20:02 +0100
                Re: C is not a low level language Richard Heathfield <rjh@cpax.org.uk> - 2019-02-24 19:26 +0000
                Re: C is not a low level language "R.Wieser" <address@not.available> - 2019-02-24 21:36 +0100
                Re: C is not a low level language Richard Heathfield <rjh@cpax.org.uk> - 2019-02-24 20:47 +0000
                Re: C is not a low level language The Natural Philosopher <tnp@invalid.invalid> - 2019-02-24 21:10 +0000
                Re: C is not a low level language "R.Wieser" <address@not.available> - 2019-02-25 08:25 +0100
                Re: C is not a low level language Richard Heathfield <rjh@cpax.org.uk> - 2019-02-25 12:24 +0000
                Re: C is not a low level language "R.Wieser" <address@not.available> - 2019-02-25 17:04 +0100
                Re: C is not a low level language Richard Heathfield <rjh@cpax.org.uk> - 2019-02-25 16:52 +0000
                Re: C is not a low level language Keith Thompson <kst-u@mib.org> - 2019-02-24 17:59 -0800
                Re: C is not a low level language "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-02-25 08:46 +0100
                Re: C is not a low level language "R.Wieser" <address@not.available> - 2019-02-25 09:36 +0100
                Re: C is not a low level language "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-02-25 10:13 +0100
                Re: C is not a low level language "R.Wieser" <address@not.available> - 2019-02-26 09:56 +0100
                Re: C is not a low level language Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-02-25 14:12 +0000
                Re: C is not a low level language Ahem A Rivet's Shot <steveo@eircom.net> - 2019-02-25 12:20 +0000
                Re: C is not a low level language Keith Thompson <kst-u@mib.org> - 2019-02-25 13:36 -0800
                Re: C is not a low level language Wouter Verhelst <w@uter.be> - 2019-02-25 10:29 +0200
                Re: C is not a low level language "R.Wieser" <address@not.available> - 2019-02-25 09:41 +0100
                Re: C is not a low level language Wouter Verhelst <w@uter.be> - 2019-02-25 10:55 +0200
                Re: C is not a low level language "R.Wieser" <address@not.available> - 2019-02-25 10:24 +0100
                Re: C is not a low level language The Natural Philosopher <tnp@invalid.invalid> - 2019-02-24 21:03 +0000
                Re: C is not a low level language "R.Wieser" <address@not.available> - 2019-02-25 08:58 +0100
                Re: C is not a low level language "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-02-25 09:40 +0100
                Re: C is not a low level language "R.Wieser" <address@not.available> - 2019-02-25 10:01 +0100
              Re: C is not a low level language Keith Thompson <kst-u@mib.org> - 2019-02-24 12:55 -0800
                Re: C is not a low level language "R.Wieser" <address@not.available> - 2019-02-25 08:31 +0100
            Re: C is not a low level language The Natural Philosopher <tnp@invalid.invalid> - 2019-02-24 17:42 +0000
              Re: C is not a low level language Richard Heathfield <rjh@cpax.org.uk> - 2019-02-24 18:19 +0000
            Re: C is not a low level language Bill Findlay <findlaybill@blueyonder.co.uk> - 2019-02-24 17:56 +0000
              Re: C is not a low level language Richard Heathfield <rjh@cpax.org.uk> - 2019-02-24 18:23 +0000
                Re: C is not a low level language The Natural Philosopher <tnp@invalid.invalid> - 2019-02-24 20:58 +0000
              Re: C is not a low level language The Natural Philosopher <tnp@invalid.invalid> - 2019-02-24 20:52 +0000
                Re: C is not a low level language Bill Findlay <findlaybill@blueyonder.co.uk> - 2019-02-25 16:31 +0000
              Re: C is not a low level language Keith Thompson <kst-u@mib.org> - 2019-02-25 14:01 -0800
                Re: C is not a low level language scott@slp53.sl.home (Scott Lurndal) - 2019-02-25 23:04 +0000
                Re: C is not a low level language Keith Thompson <kst-u@mib.org> - 2019-02-25 15:53 -0800
                Re: C is not a low level language Bill Findlay <findlaybill@blueyonder.co.uk> - 2019-02-28 16:07 +0000
              Re: C is not a low level language Björn Lundin <b.f.lundin@gmail.com> - 2019-02-25 20:50 +0100
                Re: C is not a low level language Bill Findlay <findlaybill@blueyonder.co.uk> - 2019-02-28 16:04 +0000
                Re: C is not a low level language "J. P. Gilliver (John)" <G6JPG-255@255soft.uk> - 2019-02-28 16:25 +0000
                Re: C is not a low level language "Mayayana" <mayayana@invalid.nospam> - 2019-02-28 11:56 -0500
                Re: C is not a low level language "NY" <me@privacy.net> - 2019-02-28 19:45 +0000
              Re: C is not a low level language Bart <bc@freeuk.com> - 2019-02-25 17:55 +0000
                Re: C is not a low level language Bill Findlay <findlaybill@blueyonder.co.uk> - 2019-02-28 16:03 +0000
                Re: C is not a low level language Keith Thompson <kst-u@mib.org> - 2019-02-28 11:25 -0800
                Re: C is not a low level language Bart <bc@freeuk.com> - 2019-02-28 19:30 +0000
          Re: C is not a low level language Jasen Betts <jasen@xnet.co.nz> - 2019-02-24 20:47 +0000
            Re: C is not a low level language The Natural Philosopher <tnp@invalid.invalid> - 2019-02-24 21:29 +0000
              Re: C is not a low level language Jasen Betts <jasen@xnet.co.nz> - 2019-02-25 20:16 +0000
      Re: C is not a low level language Keith Thompson <kst-u@mib.org> - 2019-02-24 12:53 -0800
      Re: C is not a low level language Wouter Verhelst <w@uter.be> - 2019-02-25 09:49 +0200
    Re: C is not a low level language Björn Lundin <b.f.lundin@gmail.com> - 2019-02-25 21:07 +0100
      Re: C is not a low level language Ahem A Rivet's Shot <steveo@eircom.net> - 2019-02-25 22:59 +0000
        Re: C is not a low level language Björn Lundin <b.f.lundin@gmail.com> - 2019-02-26 09:57 +0100
          Re: C is not a low level language Ahem A Rivet's Shot <steveo@eircom.net> - 2019-02-26 09:59 +0000
  Re: C is not a low level language Eric Stevens <eric.stevens@sum.co.nz> - 2019-02-24 19:54 +1300
    Re: C is not a low level language Ahem A Rivet's Shot <steveo@eircom.net> - 2019-02-24 07:56 +0000
      Re: C is not a low level language Eric Stevens <eric.stevens@sum.co.nz> - 2019-02-24 21:58 +1300
        Re: C is not a low level language "A. Dumas" <alexandre@dumas.fr.invalid> - 2019-02-24 10:57 +0100
        Re: C is not a low level language Ahem A Rivet's Shot <steveo@eircom.net> - 2019-02-24 10:13 +0000
        Re: C is not a low level language The Natural Philosopher <tnp@invalid.invalid> - 2019-02-24 10:47 +0000
          Re: C is not a low level language "Mayayana" <mayayana@invalid.nospam> - 2019-02-24 08:48 -0500
            Re: C is not a low level language The Natural Philosopher <tnp@invalid.invalid> - 2019-02-24 14:42 +0000
            Re: C is not a low level language Ahem A Rivet's Shot <steveo@eircom.net> - 2019-02-25 07:15 +0000
              Re: C is not a low level language "Mayayana" <mayayana@invalid.nospam> - 2019-02-25 09:25 -0500
                Re: C is not a low level language Ahem A Rivet's Shot <steveo@eircom.net> - 2019-02-25 15:03 +0000
                Re: C is not a low level language "Mayayana" <mayayana@invalid.nospam> - 2019-02-25 12:10 -0500
                Re: C is not a low level language Ahem A Rivet's Shot <steveo@eircom.net> - 2019-02-25 17:58 +0000
                Re: C is not a low level language Axel Berger <Spam@Berger-Odenthal.De> - 2019-02-25 17:44 +0100
                Re: C is not a low level language Wouter Verhelst <w@uter.be> - 2019-02-25 19:18 +0200
            Re: C is not a low level language Wouter Verhelst <w@uter.be> - 2019-02-25 10:35 +0200
              Re: C is not a low level language "J. P. Gilliver (John)" <G6JPG-255@255soft.uk> - 2019-02-25 10:44 +0000
                Re: C is not a low level language Richard Heathfield <rjh@cpax.org.uk> - 2019-02-25 12:29 +0000
                Re: C is not a low level language Ahem A Rivet's Shot <steveo@eircom.net> - 2019-02-25 14:26 +0000
                Re: C is not a low level language "NY" <me@privacy.net> - 2019-02-25 17:08 +0000
                Re: C is not a low level language Wouter Verhelst <w@uter.be> - 2019-02-25 20:08 +0200
                Re: C is not a low level language Ahem A Rivet's Shot <steveo@eircom.net> - 2019-02-25 18:00 +0000
                Re: C is not a low level language Keith Thompson <kst-u@mib.org> - 2019-02-27 22:37 -0800
                Re: C is not a low level language Keith Thompson <kst-u@mib.org> - 2019-02-28 02:25 -0800
                Re: C is not a low level language Diesel <nobody@haph.org> - 2019-03-05 04:29 +0000
              Re: C is not a low level language Ahem A Rivet's Shot <steveo@eircom.net> - 2019-02-25 12:27 +0000
              Re: C is not a low level language "Mayayana" <mayayana@invalid.nospam> - 2019-02-25 09:36 -0500
                Re: C is not a low level language Ahem A Rivet's Shot <steveo@eircom.net> - 2019-02-25 15:05 +0000
                Re: C is not a low level language Wouter Verhelst <w@uter.be> - 2019-02-25 19:20 +0200
                Re: C is not a low level language Ahem A Rivet's Shot <steveo@eircom.net> - 2019-02-25 23:02 +0000
                Re: C is not a low level language Ahem A Rivet's Shot <steveo@eircom.net> - 2019-02-26 06:52 +0000
                Re: C is not a low level language Wouter Verhelst <w@uter.be> - 2019-02-26 12:41 +0200
                Re: C is not a low level language Ahem A Rivet's Shot <steveo@eircom.net> - 2019-02-26 12:20 +0000
                Re: C is not a low level language David Brown <david.brown@hesbynett.no> - 2019-02-26 14:01 +0100
                Re: C is not a low level language "Mayayana" <mayayana@invalid.nospam> - 2019-02-26 08:48 -0500
                Re: C is not a low level language Björn Lundin <b.f.lundin@gmail.com> - 2019-02-26 19:20 +0100
              Re: C is not a low level language Wolf K <wolfmac@sympatico.ca> - 2019-02-25 10:04 -0500
        Re: C is not a low level language lonelydad <lonelydad58@gmail.com> - 2019-02-24 14:44 +0000
        Re: C is not a low level language "U-laptop\\Norah" <Norah@laptop.i-did-not-set--mail-host-address--so-tickle-me> - 2019-02-27 16:16 -0600
          Re: C is not a low level language Eric Stevens <eric.stevens@sum.co.nz> - 2019-03-01 12:12 +1300
            Re: C is not a low level language Richard Heathfield <rjh@cpax.org.uk> - 2019-03-01 00:19 +0000
      Re: C is not a low level language Gene Wirchenko <genew@telus.net> - 2019-02-24 19:59 -0800
        Re: C is not a low level language Bill Findlay <findlaybill@blueyonder.co.uk> - 2019-02-25 16:10 +0000
        Re: C is not a low level language Björn Lundin <b.f.lundin@gmail.com> - 2019-02-25 21:02 +0100
          Re: C is not a low level language Lars Enderin <lars.enderin@telia.com> - 2019-02-26 00:37 +0100
            Re: C is not a low level language Wolf K <wolfmac@sympatico.ca> - 2019-02-25 19:09 -0500
            Re: C is not a low level language Ahem A Rivet's Shot <steveo@eircom.net> - 2019-02-26 06:52 +0000
    Re: C is not a low level language T <T@invalid.invalid> - 2019-02-24 00:30 -0800
      Re: C is not a low level language T <T@invalid.invalid> - 2019-02-24 00:31 -0800
      Re: C is not a low level language Ahem A Rivet's Shot <steveo@eircom.net> - 2019-02-24 10:16 +0000
    Re: C is not a low level language "J. P. Gilliver (John)" <G6JPG-255@255soft.uk> - 2019-02-24 11:22 +0000
      Re: C is not a low level language "Mayayana" <mayayana@invalid.nospam> - 2019-02-24 08:51 -0500
        Re: C is not a low level language pyotr filipivich <phamp@mindspring.com> - 2019-02-24 07:20 -0800
          Re: C is not a low level language "J. P. Gilliver (John)" <G6JPG-255@255soft.uk> - 2019-02-24 15:35 +0000
            Re: C is not a low level language "Mayayana" <mayayana@invalid.nospam> - 2019-02-24 11:05 -0500
            Re: C is not a low level language pyotr filipivich <phamp@mindspring.com> - 2019-02-24 14:39 -0800
              Re: C is not a low level language Keith Thompson <kst-u@mib.org> - 2019-02-24 19:11 -0800
              Re: C is not a low level language Wolf K <wolfmac@sympatico.ca> - 2019-02-25 09:41 -0500
                Re: C is not a low level language "J. P. Gilliver (John)" <G6JPG-255@255soft.uk> - 2019-02-25 14:53 +0000
                Re: C is not a low level language Wolf K <wolfmac@sympatico.ca> - 2019-02-25 10:19 -0500
                Re: C is not a low level language David Brown <david.brown@hesbynett.no> - 2019-02-25 16:38 +0100
                Re: C is not a low level language Wolf K <wolfmac@sympatico.ca> - 2019-02-25 11:20 -0500
                Re: C is not a low level language "J. P. Gilliver (John)" <G6JPG-255@255soft.uk> - 2019-02-25 17:49 +0000
                Re: C is not a low level language David Brown <david.brown@hesbynett.no> - 2019-02-26 09:18 +0100
                Re: C is not a low level language nospam <nospam@nospam.invalid> - 2019-02-25 12:17 -0500
                Re: C is not a low level language Wouter Verhelst <w@uter.be> - 2019-02-25 20:25 +0200
                Re: C is not a low level language nospam <nospam@nospam.invalid> - 2019-02-25 13:40 -0500
                Re: C is not a low level language Wouter Verhelst <w@uter.be> - 2019-02-26 12:45 +0200
                Re: C is not a low level language nospam <nospam@nospam.invalid> - 2019-02-26 08:02 -0500
                Re: C is not a low level language Wolf K <wolfmac@sympatico.ca> - 2019-02-26 09:11 -0500
                Re: C is not a low level language Diesel <nobody@haph.org> - 2019-03-05 04:29 +0000
                Re: C is not a low level language David Brown <david.brown@hesbynett.no> - 2019-02-26 09:23 +0100
                Re: C is not a low level language nospam <nospam@nospam.invalid> - 2019-02-26 08:02 -0500
                Re: C is not a low level language Wouter Verhelst <w@uter.be> - 2019-02-26 17:57 +0200
                Re: C is not a low level language Diesel <nobody@haph.org> - 2019-03-05 04:29 +0000
                Re: C is not a low level language nospam <nospam@nospam.invalid> - 2019-02-25 17:42 -0500
                Re: C is not a low level language Bart <bc@freeuk.com> - 2019-02-25 22:33 +0000
                Re: C is not a low level language David Brown <david.brown@hesbynett.no> - 2019-02-26 09:30 +0100
                Re: C is not a low level language nospam <nospam@nospam.invalid> - 2019-02-25 12:17 -0500
                Re: C is not a low level language Keith Thompson <kst-u@mib.org> - 2019-02-25 13:52 -0800
                Re: C is not a low level language "NY" <me@privacy.net> - 2019-02-25 15:20 +0000
                Re: C is not a low level language nospam <nospam@nospam.invalid> - 2019-02-25 12:17 -0500
                Re: C is not a low level language Bart <bc@freeuk.com> - 2019-02-25 18:47 +0000
                Re: C is not a low level language nospam <nospam@nospam.invalid> - 2019-02-25 13:50 -0500
                Re: C is not a low level language Bart <bc@freeuk.com> - 2019-02-25 18:59 +0000
                Re: C is not a low level language Wouter Verhelst <w@uter.be> - 2019-02-25 20:15 +0200
                Re: C is not a low level language scott@slp53.sl.home (Scott Lurndal) - 2019-02-25 18:38 +0000
                Re: C is not a low level language Wouter Verhelst <w@uter.be> - 2019-02-26 12:49 +0200
                Re: C is not a low level language nospam <nospam@nospam.invalid> - 2019-02-25 13:40 -0500
                Re: C is not a low level language Wouter Verhelst <w@uter.be> - 2019-02-26 12:55 +0200
                Re: C is not a low level language scott@slp53.sl.home (Scott Lurndal) - 2019-02-26 16:29 +0000
                Re: C is not a low level language Diesel <nobody@haph.org> - 2019-03-05 04:29 +0000
                Re: C is not a low level language nospam <nospam@nospam.invalid> - 2019-03-04 23:43 -0500
                Re: C is not a low level language "NY" <me@privacy.net> - 2019-02-25 18:16 +0000
                Re: C is not a low level language "NY" <me@privacy.net> - 2019-02-25 17:44 +0000
                Re: C is not a low level language nospam <nospam@nospam.invalid> - 2019-02-25 13:05 -0500
                Re: C is not a low level language Robert Wessel <robertwessel2@yahoo.com> - 2019-02-26 00:51 -0600
                Re: C is not a low level language "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-02-26 10:58 +0100
                Re: C is not a low level language Robert Wessel <robertwessel2@yahoo.com> - 2019-02-26 10:53 -0600
                Re: C is not a low level language Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-02-26 17:49 +0000
                Re: C is not a low level language scott@slp53.sl.home (Scott Lurndal) - 2019-02-26 18:11 +0000
                Re: C is not a low level language Bart <bc@freeuk.com> - 2019-02-26 18:24 +0000
                Re: C is not a low level language "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-02-26 19:24 +0100
                Re: C is not a low level language "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-02-26 19:44 +0100
                Re: C is not a low level language nobody@example.org (Scott) - 2019-02-26 06:33 +0000
                Re: C is not a low level language nospam <nospam@nospam.invalid> - 2019-02-25 12:17 -0500
        Re: C is not a low level language Gene Wirchenko <genew@telus.net> - 2019-02-24 20:03 -0800
      Re: C is not a low level language pyotr filipivich <phamp@mindspring.com> - 2019-02-24 14:56 -0800
  Re: C is not a low level language Jasen Betts <jasen@xnet.co.nz> - 2019-02-24 20:43 +0000
    Re: C is not a low level language "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2019-02-25 14:14 +0800
      Re: C is not a low level language "J. P. Gilliver (John)" <G6JPG-255@255soft.uk> - 2019-02-25 10:45 +0000
        Re: C is not a low level language "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2019-02-25 19:04 +0800

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