[patch] Correct range checking in mallopt/mxfast/tcache [BZ #25194]

[Carlos O'Donell]

On 12/3/19 11:47 PM, DJ Delorie wrote:
> "Carlos O'Donell" <codonell@redhat.com> writes:
>> Does this allow mallopt to accept an invalid large negative 
>> value but after wrapping be treated as less than MAX_TCACHE_SIZE
>> and thus be accepted instead of rejected?
> 
> Only if sizeof(int) > sizeof(size_t), which for our targets never
> happens.  Negative values passed to mallopt will now result in failure,
> because they'll map to positive size_t larger than MAX_TCACHE_SIZE.

> Plus MAX_TCACHE_SIZE is "very small"
 
I would accept:

* Proper range checking in mallopt.
* Documentation in a comment that this is safe with an example.

-- 
Cheers,
Carlos.