1 files changed, 27 insertions, 14 deletions

diff --git a/include/linux/slab.h b/include/linux/slab.h
index 50697a1d6621..231abc8976c5 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -135,9 +135,15 @@ struct mem_cgroup;
 void __init kmem_cache_init(void);
 bool slab_is_available(void);
 
-struct kmem_cache *kmem_cache_create(const char *, size_t, size_t,
-                        slab_flags_t,
-                        void (*)(void *));
+extern bool usercopy_fallback;
+
+struct kmem_cache *kmem_cache_create(const char *name, size_t size,
+                        size_t align, slab_flags_t flags,
+                        void (*ctor)(void *));
+struct kmem_cache *kmem_cache_create_usercopy(const char *name,
+                        size_t size, size_t align, slab_flags_t flags,
+                        size_t useroffset, size_t usersize,
+                        void (*ctor)(void *));
 void kmem_cache_destroy(struct kmem_cache *);
 int kmem_cache_shrink(struct kmem_cache *);
 
@@ -153,9 +159,20 @@ void memcg_destroy_kmem_caches(struct mem_cgroup *);
  * f.e. add ____cacheline_aligned_in_smp to the struct declaration
  * then the objects will be properly aligned in SMP configurations.
  */
-#define KMEM_CACHE(__struct, __flags) kmem_cache_create(#__struct,\
-                sizeof(struct __struct), __alignof__(struct __struct),\
-                (__flags), NULL)
+#define KMEM_CACHE(__struct, __flags)                                   \
+                kmem_cache_create(#__struct, sizeof(struct __struct),   \
+                        __alignof__(struct __struct), (__flags), NULL)
+
+/*
+ * To whitelist a single field for copying to/from usercopy, use this
+ * macro instead for KMEM_CACHE() above.
+ */
+#define KMEM_CACHE_USERCOPY(__struct, __flags, __field)                 \
+                kmem_cache_create_usercopy(#__struct,                   \
+                        sizeof(struct __struct),                        \
+                        __alignof__(struct __struct), (__flags),        \
+                        offsetof(struct __struct, __field),             \
+                        sizeof_field(struct __struct, __field), NULL)
 
 /*
  * Common kmalloc functions provided by all allocators
@@ -167,15 +184,11 @@ void kzfree(const void *);
 size_t ksize(const void *);
 
 #ifdef CONFIG_HAVE_HARDENED_USERCOPY_ALLOCATOR
-const char *__check_heap_object(const void *ptr, unsigned long n,
-                                struct page *page);
+void __check_heap_object(const void *ptr, unsigned long n, struct page *page,
+                        bool to_user);
 #else
-static inline const char *__check_heap_object(const void *ptr,
-                                              unsigned long n,
-                                              struct page *page)
-{
-        return NULL;
-}
+static inline void __check_heap_object(const void *ptr, unsigned long n,
+                                       struct page *page, bool to_user) { }
 #endif
 
 /*