RFC: malloc and secure memory.

[Carlos O'Donell]

On 9/25/20 7:39 PM, Stefan O'Rear via Libc-alpha wrote:
> On Thu, Sep 24, 2020, at 4:56 PM, Carlos O'Donell via Libc-alpha wrote:
>> In reviewing this discussion:
>> https://github.com/systemd/systemd/pull/14213
>>
>> The request is for a way to mark some allocations as "secure"
>> and to give them special properties.
>>
>> I wonder if we can't do this in some generic way:
>>
>> - Make arenas a first class construct.
>>
>> /* Get arena with special properties.  */
>> malloc_arena *secure_arena = NULL;
>> /* Get a handle to an arena that has secure heaps.  If glibc can make this
>>    kind of arena and heap then it does, otherwise it returns NULL.  */
>> secure_arena = malloc_arena_get (HEAP_SECURE);
>> /* Does this glibc support his kind of arena?  */
>> if (secure_arena == NULL)
>>   abort();
> 
> This is a bit late and I apologize, but is there any possibility of choosing
> a more descriptive name than SECURE for this?  It's extremely vague, will mean
> something different for everybody, and because security is a situational and 
> global property of systems, I would generally consider it incorrect to use
> "secure" to describe local and binary properties of subsystems.

Sure. This is an RFC and largely a proposal to simply spark some conversation
and elucidate opinions.

I like Florian's suggestion that this is largely something that could be handled
with a new API to avoid problematic use cases. And if you have a new API it need
not be a part of glibc.

-- 
Cheers,
Carlos.