mm, kasan: SLAB support

Add KASAN hooks to SLAB allocator.

This patch is based on the "mm: kasan: unified support for SLUB and SLAB
allocators" patch originally prepared by Dmitry Chernenkov.

Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrey Konovalov <adech.fo@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 43 insertions, 0 deletions

diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index 0fdc798e3ff7..839f2007a0f9 100644
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -48,6 +48,9 @@ void kasan_unpoison_task_stack(struct task_struct *task);
 void kasan_alloc_pages(struct page *page, unsigned int order);
 void kasan_free_pages(struct page *page, unsigned int order);
 
+void kasan_cache_create(struct kmem_cache *cache, size_t *size,
+                        unsigned long *flags);
+
 void kasan_poison_slab(struct page *page);
 void kasan_unpoison_object_data(struct kmem_cache *cache, void *object);
 void kasan_poison_object_data(struct kmem_cache *cache, void *object);
@@ -61,6 +64,11 @@ void kasan_krealloc(const void *object, size_t new_size);
 void kasan_slab_alloc(struct kmem_cache *s, void *object);
 void kasan_slab_free(struct kmem_cache *s, void *object);
 
+struct kasan_cache {
+        int alloc_meta_offset;
+        int free_meta_offset;
+};
+
 int kasan_module_alloc(void *addr, size_t size);
 void kasan_free_shadow(const struct vm_struct *vm);
 
@@ -76,6 +84,10 @@ static inline void kasan_disable_current(void) {}
 static inline void kasan_alloc_pages(struct page *page, unsigned int order) {}
 static inline void kasan_free_pages(struct page *page, unsigned int order) {}
 
+static inline void kasan_cache_create(struct kmem_cache *cache,
+                                      size_t *size,
+                                      unsigned long *flags) {}
+
 static inline void kasan_poison_slab(struct page *page) {}
 static inline void kasan_unpoison_object_data(struct kmem_cache *cache,
                                         void *object) {}
diff --git a/include/linux/slab.h b/include/linux/slab.h
index e4b568738ca3..aa61595a1482 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -92,6 +92,12 @@
 # define SLAB_ACCOUNT           0x00000000UL
 #endif
 
+#ifdef CONFIG_KASAN
+#define SLAB_KASAN              0x08000000UL
+#else
+#define SLAB_KASAN              0x00000000UL
+#endif
+
 /* The following flags affect the page allocator grouping pages by mobility */
 #define SLAB_RECLAIM_ACCOUNT    0x00020000UL            /* Objects are reclaimable */
 #define SLAB_TEMPORARY          SLAB_RECLAIM_ACCOUNT    /* Objects are short-lived */
diff --git a/include/linux/slab_def.h b/include/linux/slab_def.h
index e878ba35ae91..9edbbf352340 100644
--- a/include/linux/slab_def.h
+++ b/include/linux/slab_def.h
@@ -76,8 +76,22 @@ struct kmem_cache {
 #ifdef CONFIG_MEMCG
         struct memcg_cache_params memcg_params;
 #endif
+#ifdef CONFIG_KASAN
+        struct kasan_cache kasan_info;
+#endif
 
         struct kmem_cache_node *node[MAX_NUMNODES];
 };
 
+static inline void *nearest_obj(struct kmem_cache *cache, struct page *page,
+                                void *x) {
+        void *object = x - (x - page->s_mem) % cache->size;
+        void *last_object = page->s_mem + (cache->num - 1) * cache->size;
+
+        if (unlikely(object > last_object))
+                return last_object;
+        else
+                return object;
+}
+
 #endif  /* _LINUX_SLAB_DEF_H */
diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index ac5143f95ee6..665cd0cd18b8 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -130,4 +130,15 @@ static inline void *virt_to_obj(struct kmem_cache *s,
 void object_err(struct kmem_cache *s, struct page *page,
                 u8 *object, char *reason);
 
+static inline void *nearest_obj(struct kmem_cache *cache, struct page *page,
+                                void *x) {
+        void *object = x - (x - page_address(page)) % cache->size;
+        void *last_object = page_address(page) +
+                (page->objects - 1) * cache->size;
+        if (unlikely(object > last_object))
+                return last_object;
+        else
+                return object;
+}
+
 #endif /* _LINUX_SLUB_DEF_H */