Check NULL pointers or not...

[Dr Paul Dale]

Oops, you are correct.  I was under the mistaken impression that ossl_assert compiled to nothing outside of debug mode.


Pauli
-- 
Dr Paul Dale | Distinguished Architect | Cryptographic Foundations 
Phone +61 7 3031 7217
Oracle Australia




> On 29 Nov 2019, at 7:22 pm, Matt Caswell <matt at openssl.org> wrote:
> 
> 
> 
> On 29/11/2019 08:38, Dr Paul Dale wrote:
>> I’d prefer option 1 or the middle ground.  I’ve lost count of the
>> number of times I’ve seen programs crashing in the crypto library
>> which required mammoth debugging efforts to irrefutably demonstrate
>> that the caller is at fault rather than the crypto library :(
>> 
>> Option 1 would be preferable from this point of view but it can cause
>> a performance hit — most of the time it wouldn’t matter but when it
>> does it would be a big deal.  The middle ground doesn’t entail any
>> performance loss in production code (it does in debug but that
>> shouldn’t be relevant).
> 
> 
> I think you misunderstand the middle ground option:
> 
>    if (!ossl_assert(ptr != NULL)) {
>        ERR_raise(ERR_LIB_WHATEVER, ERR_R_PASSED_NULL_PARAMETER);
>        return 0;
>    }
> 
> In debug code this will crash if ptr is NULL. In production code this
> acts exactly like option 1 - so has exactly the same performance hit.
> 
> For the record my preference is the middle ground option as being the
> norm for new code and where we make a significant refactor of old code.
> If something truly is performance critical then we can choose not to do
> it in those cases.
> 
> Matt
> 

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