On 5/23/23 09:42, Lorenzo Stoakes wrote:
> On Tue, May 23, 2023 at 09:31:36AM +0200, Vlastimil Babka wrote:
>> With SLOB removed, both remaining allocators support hardened usercopy,
>> so remove the config and associated #ifdef.
>>
>> Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>
>> ---
>> mm/Kconfig | 2 --
>> mm/slab.h | 9 ---------
>> security/Kconfig | 8 --------
>> 3 files changed, 19 deletions(-)
>>
>> diff --git a/mm/Kconfig b/mm/Kconfig
>> index 7672a22647b4..041f0da42f2b 100644
>> --- a/mm/Kconfig
>> +++ b/mm/Kconfig
>> @@ -221,7 +221,6 @@ choice
>> config SLAB
>> bool "SLAB"
>> depends on !PREEMPT_RT
>> - select HAVE_HARDENED_USERCOPY_ALLOCATOR
>> help
>> The regular slab allocator that is established and known to work
>> well in all environments. It organizes cache hot objects in
>> @@ -229,7 +228,6 @@ config SLAB
>>
>> config SLUB
>> bool "SLUB (Unqueued Allocator)"
>> - select HAVE_HARDENED_USERCOPY_ALLOCATOR
>> help
>> SLUB is a slab allocator that minimizes cache line usage
>> instead of managing queues of cached objects (SLAB approach).
>> diff --git a/mm/slab.h b/mm/slab.h
>> index f01ac256a8f5..695ef96b4b5b 100644
>> --- a/mm/slab.h
>> +++ b/mm/slab.h
>> @@ -832,17 +832,8 @@ struct kmem_obj_info {
>> void __kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab);
>> #endif
>>
>> -#ifdef CONFIG_HAVE_HARDENED_USERCOPY_ALLOCATOR
>> void __check_heap_object(const void *ptr, unsigned long n,
>> const struct slab *slab, bool to_user);
>> -#else
>> -static inline
>> -void __check_heap_object(const void *ptr, unsigned long n,
>> - const struct slab *slab, bool to_user)
>> -{
>> -}
>> -#endif
>
> Hm, this is still defined in slab.c/slub.c and invoked in usercopy.c, do we
> not want the prototype?
Well I didn't delete the prototype, just the ifdef/else around, so now it's
there unconditionally.
> Perhaps replacing with #ifdef
> CONFIG_HARDENED_USERCOPY instead? I may be missing something here :)
Putting it under that #ifdef would work and match that the implementations
of that function are under that same ifdef, but maybe it's unnecessary noise
in the header?
