Wireshark · Wireshark-dev: Re: [Wireshark-dev] tvb allocator (was: Re: [Wireshark-commits] master b6d20a2: Optimize reseting ep

[Bálint Réczey <balint@xxxxxxxxxxxxxxx>]

Hi Jakub,

2014-07-22 0:52 GMT+02:00  <darkjames-ws@xxxxxxxxxxxx>:
> Hi,
>
> On Sat, Jul 12, 2014 at 02:27:06AM +0200, B??lint R??czey wrote:
>> I plan using ASAN for all programs which would catch (among others)
>> use-after-free and reading below or over the malloc()-ed
>> memory area. Those can't be caught if the program uses another layer
>> of bulk memory allocations.
>> g_malloc() and g_slice_* has the same problem, but they can be
>> overrideb by passing G_SLICE=always-malloc .
>
> We have these environment variables also, ver{3, 4} introduce WIRESHARK_DEBUG_WMEM_OBJECT_POOL_SKIP,
> where you can set, and object pool will not maintain free list of objects.
>
> I see no problem with enabling it by default when building with ASAN.
>
> Also it should be quite easy to use ASAN manual poisoning[1] with object pool API.
>
> wmem_object_pool_alloc(wmem_allocator_t *allocator, wmem_object_pool_t *pool):
>     if (pool->current_count > 0) {
>         ...
>         ASAN_UNPOISON_MEMORY_REGION(pool->free_list, pool->object_size);
>         pool->free_list = pool->free_list->next;
>
> wmem_object_pool_free(wmem_allocator_t *allocator, wmem_object_pool_t *pool, void *ptr)
>     ...
>     ASAN_POISON_MEMORY_REGION(ptr, pool->object_size);
>
> (not tested).
Thank you, I was not aware of those macros. I think we should add
those to the custom allocator code.

Cheers,
Balint