[PATCH] mm/slab: remove HAVE_HARDENED_USERCOPY_ALLOCATOR

From: Vlastimil Babka
Date: Tue May 23 2023 - 03:33:03 EST


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
-
#ifdef CONFIG_SLUB_DEBUG
void skip_orig_size_check(struct kmem_cache *s, const void *object);
#endif
diff --git a/security/Kconfig b/security/Kconfig
index 97abeb9b9a19..52c9af08ad35 100644
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -127,16 +127,8 @@ config LSM_MMAP_MIN_ADDR
this low address space will need the permission specific to the
systems running LSM.

-config HAVE_HARDENED_USERCOPY_ALLOCATOR
- bool
- help
- The heap allocator implements __check_heap_object() for
- validating memory ranges against heap object sizes in
- support of CONFIG_HARDENED_USERCOPY.
-
config HARDENED_USERCOPY
bool "Harden memory copies between kernel and userspace"
- depends on HAVE_HARDENED_USERCOPY_ALLOCATOR
imply STRICT_DEVMEM
help
This option checks for obviously wrong memory regions when
--
2.40.1