[SystemSafety] C++ and Pointers

[Peter Bishop]

On 05/07/2019 12:44, Derek M Jones wrote:
> Peter,
>
>> Pointers make the software much harder to assess/statically analyse.
>
> They used to make life difficult.  But these days (for the last
> 10 years), there is lots of support for fancy pointer analysis.
>
> People also tend to overlook that most pointers only every point at one
> object, and fancy analysis is not needed to figure this out.

If only.

For the software I have been looking at recently, a pointer can point to
multiple targets
i.e. multiple functions, data, data structures, data structures
containing pointers to other objects ....

Tools like CodeSonar and Astree can handle pointers and calculate the
set of pointer values for individual code paths, but because the
analysis is path-dependent it can take many hours, or even days to do a
complete analysis.

Peter

>
> My company wrote the initial C t IL converter for the MALPAS tool,
> which was figuring this stuff out in the late 1980s.
>
>> Regards
>>
>> Peter
>>
>> On 05/07/2019 08:59, Grazebrook, Alvery AN wrote:
>>> Entertaining, but clearly a mis-quote out of context. Derek was
>>> making some (valid) comments about measuring the characteristics of
>>> buffer-overflow attacks, and then finished with:
>>> " I cannot think of any research looking at this.  Pointers welcome."
>>>
>>> Clearly not the endorsement of C++ programming that Olwen is
>>> accusing him of.
>>>
>>> Good opportunistic rant though!
>>>
>>> Cheers,
>>>     Alvery
>>>
>>> ** opinions are my own, not necessarily those of my employer
>>>
>>> -----Original Message-----
>>> From: systemsafety
>>> [mailto:systemsafety-bounces at lists.techfak.uni-bielefeld.de] On
>>> Behalf Of Olwen Morgan
>>> Sent: 04 July 2019 19:45
>>> To: systemsafety at lists.techfak.uni-bielefeld.de
>>> Subject: Re: [SystemSafety] C++ and Pointers
>>>
>>>
>>> On 06/06/2019 17:18, Derek M Jones wrote:
>>>
>>> <snip>
>>>
>>> Pointers welcome.
>>>
>>>
>>> <snip>
>>>
>>>
>>> No, pointers are *unwelcome* owing to the complexity of aliasing and
>>> overflow problems they create. You can create efficient and secure
>>> large-scale services very easily with applicative/concurrent
>>> languages like Erlang.
>>>
>>> Software engineers who write critical systems in C++ should be sent
>>> to gulags to do more useful work.
>>>
>>>
>>> How long does one have to keep on saying these things before the
>>> lumpen-engineeriate finally gets it?
>>>
>>> Yawn,
>>>
>>> Olwen
>>>
>>>
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>>
>
-- 
Peter Bishop
Chief Scientist
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