Re: VMS

From	Robert Riches <spamtrap42@jacob21819.net>
Newsgroups	comp.os.linux.misc
Subject	Re: VMS
Date	2025-06-24 03:34 +0000
Organization	none-at-all
Message-ID	<slrn105k75h.h13.spamtrap42@one.localnet> (permalink)
References	(11 earlier) <1033tv1$3aqu$3@dont-email.me> <1034pj8$a74s$1@dont-email.me> <mbmm2nFdsgcU2@mid.individual.net> <slrn105cajs.4vj.spamtrap42@one.localnet> <slrn105g20l.3q8n7.candycanearter07@candydeb.host.invalid>

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On 2025-06-22, candycanearter07 <candycanearter07@candycanearter07.nomail.afraid> wrote:
> Robert Riches <spamtrap42@jacob21819.net> wrote at 03:43 this Saturday (GMT):
>> On 2025-06-21, rbowman <bowman@montana.com> wrote:
>>> On Fri, 20 Jun 2025 23:07:20 -0000 (UTC), Rich wrote:
>>>
>>>> Very likely, but the idea was to protect the typical programmer from
>>>> their own common mistakes (of not carefully checking error return codes
>>>> or buffer lengths, etc.).  I.e. the typical 9-5 contract programmer, not
>>>> the Dennis Ritchie's of the world.
>>>
>>> I'm paranoid enough that I check the return of malloc and try to log the 
>>> problem even though I'm probably screwed at that point. It has pointed out 
>>> errors for calloc if you've manged to come up with a negative size.
>>>
>>> I have worked with programmers that assumed nothing bad would ever happen. 
>>> Sadly, some had years of experience.
>>
>> Some years ago, I heard of a bug related to use of malloc.  The
>> code had _intended_ to dynamically allocate storage for a string
>> and the terminating null byte.  It was _intended_ to do this:
>>
>>         dest = malloc(strlen(src)+1);
>>
>> Instead, a paren was misplaced:
>>
>>         dest = malloc(strlen(src))+1;
>>
>> IIUC, the next line copied the src string into the newly-
>> allocated destination.
>
> Aren't you supposed to multiply by sizeof as well?

Multiply by sizeof what?  sizeof(char)?  This was in the
pre-Unicode days.  Even now with Unicode, IIUC sizeof(char) is
still always 1.

>> Those who had worked on that project longer said the bug had been
>> latent in the code for several years, most likely with alignment
>> padding masking the bug from being discovered.  Curiously, the
>> bug made itself manifest immediately upon changing from a 32-bit
>> build environment to a 64-bit build environment.
>
>
> I'm more surprised it didn't segfault. Any idea what caused it to not?
> I know strlen doesn't account for the terminating character, but it
> seems like it should've been TWO bytes shorter...

IIUC, heap-based malloc _usually_ returns a larger allocation
block than you really asked for.  As long as malloc gave you at
least 2 extra bytes, you'd never see any misbehavior.  Even if it
didn't give you 2 or more extra bytes, it's fairly likely you'd
just get lucky and never see the program crash or otherwise
misbehavior in a significant way.  For example, if you stomped on
the header of the next allocation block, as long as nothing ever
read and acted upon the data in said header, you'd never see it.

-- 
Robert Riches
spamtrap42@jacob21819.net
(Yes, that is one of my email addresses.)

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VMS c186282 <c186282@nnada.net> - 2025-06-14 01:15 -0400
  Re: VMS Bobbie Sellers <bliss-sf4ever@dslextreme.com> - 2025-06-14 10:05 -0700
    Re: VMS Andreas Eder <a_eder_muc@web.de> - 2025-06-14 20:30 +0200
      Re: VMS Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-06-14 23:27 +0000
        Re: VMS rbowman <bowman@montana.com> - 2025-06-15 00:57 +0000
          Re: VMS c186282 <c186282@nnada.net> - 2025-06-14 23:32 -0400
            Re: VMS The Natural Philosopher <tnp@invalid.invalid> - 2025-06-15 08:26 +0100
              Re: VMS c186282 <c186282@nnada.net> - 2025-06-15 21:12 -0400
                Re: VMS Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2025-06-16 18:15 +0000
                Re: VMS c186282 <c186282@nnada.net> - 2025-06-17 23:20 -0400
                Re: VMS rbowman <bowman@montana.com> - 2025-06-18 04:14 +0000
                Re: VMS c186282 <c186282@nnada.net> - 2025-06-18 02:34 -0400
            Re: VMS rbowman <bowman@montana.com> - 2025-06-15 18:49 +0000
              Re: VMS c186282 <c186282@nnada.net> - 2025-06-15 22:45 -0400
                Re: VMS rbowman <bowman@montana.com> - 2025-06-16 04:35 +0000
                Re: VMS c186282 <c186282@nnada.net> - 2025-06-16 01:35 -0400
        Re: VMS c186282 <c186282@nnada.net> - 2025-06-14 23:03 -0400
          Re: VMS candycanearter07 <candycanearter07@candycanearter07.nomail.afraid> - 2025-06-18 05:30 +0000
            Re: VMS c186282 <c186282@nnada.net> - 2025-06-18 02:09 -0400
              Re: VMS candycanearter07 <candycanearter07@candycanearter07.nomail.afraid> - 2025-06-18 19:00 +0000
                Re: VMS Rich <rich@example.invalid> - 2025-06-18 20:23 +0000
                Re: VMS Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2025-06-18 20:30 +0000
                Re: VMS rbowman <bowman@montana.com> - 2025-06-18 23:09 +0000
              Re: VMS Richard Kettlewell <invalid@invalid.invalid> - 2025-06-19 08:40 +0100
                Re: VMS c186282 <c186282@nnada.net> - 2025-06-20 00:43 -0400
                Re: VMS Richard Kettlewell <invalid@invalid.invalid> - 2025-06-20 09:00 +0100
                Re: VMS The Natural Philosopher <tnp@invalid.invalid> - 2025-06-20 10:19 +0100
                Re: VMS Richard Kettlewell <invalid@invalid.invalid> - 2025-06-20 15:15 +0100
                Re: VMS Rich <rich@example.invalid> - 2025-06-20 13:36 +0000
                Re: VMS The Natural Philosopher <tnp@invalid.invalid> - 2025-06-20 16:15 +0100
                Re: VMS Rich <rich@example.invalid> - 2025-06-20 23:07 +0000
                Re: VMS The Natural Philosopher <tnp@invalid.invalid> - 2025-06-21 01:07 +0100
                Re: VMS rbowman <bowman@montana.com> - 2025-06-21 03:09 +0000
                Re: VMS Robert Riches <spamtrap42@jacob21819.net> - 2025-06-21 03:43 +0000
                Re: VMS c186282 <c186282@nnada.net> - 2025-06-21 01:36 -0400
                Re: VMS rbowman <bowman@montana.com> - 2025-06-21 05:53 +0000
                Re: VMS candycanearter07 <candycanearter07@candycanearter07.nomail.afraid> - 2025-06-22 13:50 +0000
                Re: VMS Richard Kettlewell <invalid@invalid.invalid> - 2025-06-22 15:27 +0100
                Re: VMS The Natural Philosopher <tnp@invalid.invalid> - 2025-06-22 15:56 +0100
                Re: VMS c186282 <c186282@nnada.net> - 2025-06-23 00:18 -0400
                Re: VMS rbowman <bowman@montana.com> - 2025-06-22 19:23 +0000
                Re: VMS candycanearter07 <candycanearter07@candycanearter07.nomail.afraid> - 2025-06-23 18:10 +0000
                Re: VMS rbowman <bowman@montana.com> - 2025-06-23 19:27 +0000
                Re: VMS Robert Riches <spamtrap42@jacob21819.net> - 2025-06-24 03:34 +0000
                Re: VMS Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2025-06-24 04:52 +0000
                Re: VMS rbowman <bowman@montana.com> - 2025-06-24 05:14 +0000
                Re: VMS c186282 <c186282@nnada.net> - 2025-06-24 01:36 -0400
                Re: VMS rbowman <bowman@montana.com> - 2025-06-24 06:49 +0000
                Re: VMS The Natural Philosopher <tnp@invalid.invalid> - 2025-06-24 10:31 +0100
                Re: VMS c186282 <c186282@nnada.net> - 2025-06-25 01:36 -0400
                Re: VMS The Natural Philosopher <tnp@invalid.invalid> - 2025-06-25 07:31 +0100
                Re: VMS c186282 <c186282@nnada.net> - 2025-06-25 03:08 -0400
                Re: VMS Richard Kettlewell <invalid@invalid.invalid> - 2025-06-24 08:56 +0100
                Re: VMS Robert Riches <spamtrap42@jacob21819.net> - 2025-06-25 03:01 +0000
                Re: VMS c186282 <c186282@nnada.net> - 2025-06-25 01:59 -0400
                Re: VMS rbowman <bowman@montana.com> - 2025-06-25 06:52 +0000
                Re: VMS John Ames <commodorejohn@gmail.com> - 2025-06-25 09:32 -0700
                Re: VMS John Ames <commodorejohn@gmail.com> - 2025-06-25 09:44 -0700
                Re: VMS c186282 <c186282@nnada.net> - 2025-06-25 19:01 -0400
                Re: VMS candycanearter07 <candycanearter07@candycanearter07.nomail.afraid> - 2025-06-27 06:00 +0000
                Re: VMS Richard Kettlewell <invalid@invalid.invalid> - 2025-06-27 08:37 +0100
                Re: VMS The Natural Philosopher <tnp@invalid.invalid> - 2025-06-27 08:45 +0100
                Re: VMS Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-06-27 08:14 +0000
                Re: VMS c186282 <c186282@nnada.net> - 2025-06-27 13:27 -0400
                Re: VMS The Natural Philosopher <tnp@invalid.invalid> - 2025-06-27 19:13 +0100
                Re: VMS Chris Ahlstrom <OFeem1987@teleworm.us> - 2025-06-28 09:16 -0400
                Re: VMS c186282 <c186282@nnada.net> - 2025-06-27 13:24 -0400
                Re: VMS rbowman <bowman@montana.com> - 2025-06-27 17:40 +0000
                Re: VMS Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2025-06-27 18:20 +0000
                Re: VMS Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-06-27 23:03 +0000
                Re: VMS c186282 <c186282@nnada.net> - 2025-06-28 01:13 -0400
                Re: VMS rbowman <bowman@montana.com> - 2025-06-28 06:10 +0000
                Re: VMS c186282 <c186282@nnada.net> - 2025-06-27 18:16 -0400
                Re: VMS Richard Kettlewell <invalid@invalid.invalid> - 2025-06-28 08:52 +0100
                Re: VMS c186282 <c186282@nnada.net> - 2025-06-28 23:16 -0400
                Re: VMS Richard Kettlewell <invalid@invalid.invalid> - 2025-06-29 08:18 +0100
                Re: VMS c186282 <c186282@nnada.net> - 2025-06-29 19:09 -0400
                Re: VMS The Natural Philosopher <tnp@invalid.invalid> - 2025-06-30 08:36 +0100
                Re: VMS Richard Kettlewell <invalid@invalid.invalid> - 2025-06-30 08:51 +0100
                Re: VMS The Natural Philosopher <tnp@invalid.invalid> - 2025-06-30 08:59 +0100
                Re: VMS Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-06-30 08:33 +0000
                Re: VMS John Ames <commodorejohn@gmail.com> - 2025-06-30 09:08 -0700
                Re: VMS jayjwa <jayjwa@atr2.ath.cx.invalid> - 2025-06-30 22:18 -0400
                Re: VMS Richard Kettlewell <invalid@invalid.invalid> - 2025-06-30 09:00 +0100
                Re: VMS The Natural Philosopher <tnp@invalid.invalid> - 2025-06-30 09:24 +0100
                Re: VMS Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-06-30 08:34 +0000
                Re: VMS c186282 <c186282@nnada.net> - 2025-06-30 23:30 -0400
                Re: VMS c186282 <c186282@nnada.net> - 2025-06-30 23:26 -0400
                Re: VMS The Natural Philosopher <tnp@invalid.invalid> - 2025-07-01 10:49 +0100
                Re: VMS Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2025-07-01 12:44 +0000
                Re: VMS Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2025-07-02 01:13 +0000
                Re: VMS c186282 <c186282@nnada.net> - 2025-07-01 21:46 -0400
                Re: VMS Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2025-07-02 16:03 +0000
                Re: VMS Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-06-30 07:54 +0000
                Re: VMS rbowman <bowman@montana.com> - 2025-06-30 18:10 +0000
                Re: VMS c186282 <c186282@nnada.net> - 2025-06-30 23:12 -0400
                Re: VMS rbowman <bowman@montana.com> - 2025-07-01 04:02 +0000
                Re: VMS c186282 <c186282@nnada.net> - 2025-07-01 12:42 -0400
                Re: VMS Richard Kettlewell <invalid@invalid.invalid> - 2025-06-30 08:56 +0100
                Re: VMS Rich <rich@example.invalid> - 2025-06-27 19:40 +0000
                Re: VMS Richard Kettlewell <invalid@invalid.invalid> - 2025-06-20 21:19 +0100
                Re: VMS Rich <rich@example.invalid> - 2025-06-20 23:17 +0000
                Re: VMS Richard Kettlewell <invalid@invalid.invalid> - 2025-06-21 08:42 +0100
                Re: VMS Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-06-21 07:02 +0000
                Re: VMS c186282 <c186282@nnada.net> - 2025-06-21 03:23 -0400
                Re: VMS c186282 <c186282@nnada.net> - 2025-06-21 01:27 -0400
                Re: VMS c186282 <c186282@nnada.net> - 2025-06-21 01:10 -0400
                Re: VMS rbowman <bowman@montana.com> - 2025-06-21 05:59 +0000
                Re: VMS c186282 <c186282@nnada.net> - 2025-06-21 02:10 -0400
                Re: VMS The Natural Philosopher <tnp@invalid.invalid> - 2025-06-20 10:12 +0100
                Re: VMS Rich <rich@example.invalid> - 2025-06-20 13:39 +0000
                Re: VMS c186282 <c186282@nnada.net> - 2025-06-21 01:23 -0400
                Re: VMS Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-06-21 06:57 +0000
                Re: VMS c186282 <c186282@nnada.net> - 2025-06-21 03:07 -0400
                Re: VMS Richard Kettlewell <invalid@invalid.invalid> - 2025-06-21 08:45 +0100
                Re: VMS c186282 <c186282@nnada.net> - 2025-06-22 02:32 -0400
                Re: VMS Rich <rich@example.invalid> - 2025-06-20 13:30 +0000
                Re: VMS The Natural Philosopher <tnp@invalid.invalid> - 2025-06-20 16:14 +0100
                Re: VMS Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-06-20 08:57 +0000
                Re: VMS c186282 <c186282@nnada.net> - 2025-06-21 01:17 -0400
    Re: VMS c186282 <c186282@nnada.net> - 2025-06-14 22:57 -0400
      Re: VMS Rich <rich@example.invalid> - 2025-06-15 14:24 +0000
        Re: VMS c186282 <c186282@nnada.net> - 2025-06-15 22:26 -0400
          Re: VMS rbowman <bowman@montana.com> - 2025-06-16 04:30 +0000
            Re: VMS c186282 <c186282@nnada.net> - 2025-06-16 01:31 -0400
            Re: VMS Rich <rich@example.invalid> - 2025-06-18 17:40 +0000
              Re: VMS rbowman <bowman@montana.com> - 2025-06-18 23:06 +0000
              Re: VMS c186282 <c186282@nnada.net> - 2025-06-18 19:43 -0400
                Re: VMS Rich <rich@example.invalid> - 2025-06-19 01:08 +0000
                Re: VMS c186282 <c186282@nnada.net> - 2025-06-19 00:46 -0400
                Re: VMS rbowman <bowman@montana.com> - 2025-06-19 06:36 +0000

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