mm, kasan: switch SLUB to stackdepot, enable memory quarantine for SLUB

For KASAN builds:
 - switch SLUB allocator to using stackdepot instead of storing the
   allocation/deallocation stacks in the objects;
 - change the freelist hook so that parts of the freelist can be put
   into the quarantine.

[aryabinin@virtuozzo.com: fixes]
  Link: http://lkml.kernel.org/r/1468601423-28676-1-git-send-email-aryabinin@virtuozzo.com
Link: http://lkml.kernel.org/r/1468347165-41906-3-git-send-email-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <adech.fo@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Steven Rostedt (Red Hat) <rostedt@goodmis.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Kuthonuzo Luruo <kuthonuzo.luruo@hpe.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 37 insertions, 40 deletions

diff --git a/mm/kasan/Makefile b/mm/kasan/Makefile
index 1548749..2976a9e 100644
--- a/mm/kasan/Makefile
+++ b/mm/kasan/Makefile
@@ -7,5 +7,4 @@ CFLAGS_REMOVE_kasan.o = -pg
 # see: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63533
 CFLAGS_kasan.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector)
 
-obj-y := kasan.o report.o kasan_init.o
-obj-$(CONFIG_SLAB) += quarantine.o
+obj-y := kasan.o report.o kasan_init.o quarantine.o
diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c
index 6845f92..b6f99e8 100644
--- a/mm/kasan/kasan.c
+++ b/mm/kasan/kasan.c
@@ -351,7 +351,6 @@ void kasan_free_pages(struct page *page, unsigned int order)
 				KASAN_FREE_PAGE);
 }
 
-#ifdef CONFIG_SLAB
 /*
  * Adaptive redzone policy taken from the userspace AddressSanitizer runtime.
  * For larger allocations larger redzones are used.
@@ -373,16 +372,8 @@ void kasan_cache_create(struct kmem_cache *cache, size_t *size,
 			unsigned long *flags)
 {
 	int redzone_adjust;
-	/* Make sure the adjusted size is still less than
-	 * KMALLOC_MAX_CACHE_SIZE.
-	 * TODO: this check is only useful for SLAB, but not SLUB. We'll need
-	 * to skip it for SLUB when it starts using kasan_cache_create().
-	 */
-	if (*size > KMALLOC_MAX_CACHE_SIZE -
-	    sizeof(struct kasan_alloc_meta) -
-	    sizeof(struct kasan_free_meta))
-		return;
-	*flags |= SLAB_KASAN;
+	int orig_size = *size;
+
 	/* Add alloc meta. */
 	cache->kasan_info.alloc_meta_offset = *size;
 	*size += sizeof(struct kasan_alloc_meta);
@@ -395,14 +386,26 @@ void kasan_cache_create(struct kmem_cache *cache, size_t *size,
 	}
 	redzone_adjust = optimal_redzone(cache->object_size) -
 		(*size - cache->object_size);
+
 	if (redzone_adjust > 0)
 		*size += redzone_adjust;
-	*size = min(KMALLOC_MAX_CACHE_SIZE,
-		    max(*size,
-			cache->object_size +
-			optimal_redzone(cache->object_size)));
+
+	*size = min(KMALLOC_MAX_SIZE, max(*size, cache->object_size +
+					optimal_redzone(cache->object_size)));
+
+	/*
+	 * If the metadata doesn't fit, don't enable KASAN at all.
+	 */
+	if (*size <= cache->kasan_info.alloc_meta_offset ||
+			*size <= cache->kasan_info.free_meta_offset) {
+		cache->kasan_info.alloc_meta_offset = 0;
+		cache->kasan_info.free_meta_offset = 0;
+		*size = orig_size;
+		return;
+	}
+
+	*flags |= SLAB_KASAN;
 }
-#endif
 
 void kasan_cache_shrink(struct kmem_cache *cache)
 {
@@ -414,6 +417,14 @@ void kasan_cache_destroy(struct kmem_cache *cache)
 	quarantine_remove_cache(cache);
 }
 
+size_t kasan_metadata_size(struct kmem_cache *cache)
+{
+	return (cache->kasan_info.alloc_meta_offset ?
+		sizeof(struct kasan_alloc_meta) : 0) +
+		(cache->kasan_info.free_meta_offset ?
+		sizeof(struct kasan_free_meta) : 0);
+}
+
 void kasan_poison_slab(struct page *page)
 {
 	kasan_poison_shadow(page_address(page),
@@ -431,16 +442,13 @@ void kasan_poison_object_data(struct kmem_cache *cache, void *object)
 	kasan_poison_shadow(object,
 			round_up(cache->object_size, KASAN_SHADOW_SCALE_SIZE),
 			KASAN_KMALLOC_REDZONE);
-#ifdef CONFIG_SLAB
 	if (cache->flags & SLAB_KASAN) {
 		struct kasan_alloc_meta *alloc_info =
 			get_alloc_info(cache, object);
 		alloc_info->state = KASAN_STATE_INIT;
 	}
-#endif
 }
 
-#ifdef CONFIG_SLAB
 static inline int in_irqentry_text(unsigned long ptr)
 {
 	return (ptr >= (unsigned long)&__irqentry_text_start &&
@@ -501,7 +509,6 @@ struct kasan_free_meta *get_free_info(struct kmem_cache *cache,
 	BUILD_BUG_ON(sizeof(struct kasan_free_meta) > 32);
 	return (void *)object + cache->kasan_info.free_meta_offset;
 }
-#endif
 
 void kasan_slab_alloc(struct kmem_cache *cache, void *object, gfp_t flags)
 {
@@ -522,16 +529,16 @@ static void kasan_poison_slab_free(struct kmem_cache *cache, void *object)
 
 bool kasan_slab_free(struct kmem_cache *cache, void *object)
 {
-#ifdef CONFIG_SLAB
 	/* RCU slabs could be legally used after free within the RCU period */
 	if (unlikely(cache->flags & SLAB_DESTROY_BY_RCU))
 		return false;
 
 	if (likely(cache->flags & SLAB_KASAN)) {
-		struct kasan_alloc_meta *alloc_info =
-			get_alloc_info(cache, object);
-		struct kasan_free_meta *free_info =
-			get_free_info(cache, object);
+		struct kasan_alloc_meta *alloc_info;
+		struct kasan_free_meta *free_info;
+
+		alloc_info = get_alloc_info(cache, object);
+		free_info = get_free_info(cache, object);
 
 		switch (alloc_info->state) {
 		case KASAN_STATE_ALLOC:
@@ -550,10 +557,6 @@ bool kasan_slab_free(struct kmem_cache *cache, void *object)
 		}
 	}
 	return false;
-#else
-	kasan_poison_slab_free(cache, object);
-	return false;
-#endif
 }
 
 void kasan_kmalloc(struct kmem_cache *cache, const void *object, size_t size,
@@ -576,7 +579,6 @@ void kasan_kmalloc(struct kmem_cache *cache, const void *object, size_t size,
 	kasan_unpoison_shadow(object, size);
 	kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start,
 		KASAN_KMALLOC_REDZONE);
-#ifdef CONFIG_SLAB
 	if (cache->flags & SLAB_KASAN) {
 		struct kasan_alloc_meta *alloc_info =
 			get_alloc_info(cache, object);
@@ -585,7 +587,6 @@ void kasan_kmalloc(struct kmem_cache *cache, const void *object, size_t size,
 		alloc_info->alloc_size = size;
 		set_track(&alloc_info->track, flags);
 	}
-#endif
 }
 EXPORT_SYMBOL(kasan_kmalloc);
 
diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index fb87923..31972cd 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -95,7 +95,6 @@ struct kasan_alloc_meta *get_alloc_info(struct kmem_cache *cache,
 struct kasan_free_meta *get_free_info(struct kmem_cache *cache,
 					const void *object);
 
-
 static inline const void *kasan_shadow_to_mem(const void *shadow_addr)
 {
 	return (void *)(((unsigned long)shadow_addr - KASAN_SHADOW_OFFSET)
@@ -110,7 +109,7 @@ static inline bool kasan_report_enabled(void)
 void kasan_report(unsigned long addr, size_t size,
 		bool is_write, unsigned long ip);
 
-#ifdef CONFIG_SLAB
+#if defined(CONFIG_SLAB) || defined(CONFIG_SLUB)
 void quarantine_put(struct kasan_free_meta *info, struct kmem_cache *cache);
 void quarantine_reduce(void);
 void quarantine_remove_cache(struct kmem_cache *cache);
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index b3c122d..861b977 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -116,7 +116,6 @@ static inline bool init_task_stack_addr(const void *addr)
 			sizeof(init_thread_union.stack));
 }
 
-#ifdef CONFIG_SLAB
 static void print_track(struct kasan_track *track)
 {
 	pr_err("PID = %u\n", track->pid);
@@ -130,8 +129,8 @@ static void print_track(struct kasan_track *track)
 	}
 }
 
-static void object_err(struct kmem_cache *cache, struct page *page,
-			void *object, char *unused_reason)
+static void kasan_object_err(struct kmem_cache *cache, struct page *page,
+				void *object, char *unused_reason)
 {
 	struct kasan_alloc_meta *alloc_info = get_alloc_info(cache, object);
 	struct kasan_free_meta *free_info;
@@ -162,7 +161,6 @@ static void object_err(struct kmem_cache *cache, struct page *page,
 		break;
 	}
 }
-#endif
 
 static void print_address_description(struct kasan_access_info *info)
 {
@@ -177,7 +175,7 @@ static void print_address_description(struct kasan_access_info *info)
 			struct kmem_cache *cache = page->slab_cache;
 			object = nearest_obj(cache, page,
 						(void *)info->access_addr);
-			object_err(cache, page, object,
+			kasan_object_err(cache, page, object,
 					"kasan: bad access detected");
 			return;
 		}