X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=mm%2Fslub.c;h=41f7cae64a49bfef91d0f992df18fa4aae0cefb7;hb=edd7917229fdc03d09f45758ea674913af20a19d;hp=46997517406ede0e987388763c9fa1d07875c1db;hpb=8b9c13347a21aad4a35ac8b4214f55bc1e43ba16;p=firefly-linux-kernel-4.4.55.git

diff --git a/mm/slub.c b/mm/slub.c
index 46997517406e..41f7cae64a49 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -124,6 +124,14 @@ static inline int kmem_cache_debug(struct kmem_cache *s)
 #endif
 }
 
+static inline void *fixup_red_left(struct kmem_cache *s, void *p)
+{
+	if (kmem_cache_debug(s) && s->flags & SLAB_RED_ZONE)
+		p += s->red_left_pad;
+
+	return p;
+}
+
 static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s)
 {
 #ifdef CONFIG_SLUB_CPU_PARTIAL
@@ -224,24 +232,6 @@ static inline void stat(const struct kmem_cache *s, enum stat_item si)
  * 			Core slab cache functions
  *******************************************************************/
 
-/* Verify that a pointer has an address that is valid within a slab page */
-static inline int check_valid_pointer(struct kmem_cache *s,
-				struct page *page, const void *object)
-{
-	void *base;
-
-	if (!object)
-		return 1;
-
-	base = page_address(page);
-	if (object < base || object >= base + page->objects * s->size ||
-		(object - base) % s->size) {
-		return 0;
-	}
-
-	return 1;
-}
-
 static inline void *get_freepointer(struct kmem_cache *s, void *object)
 {
 	return *(void **)(object + s->offset);
@@ -271,12 +261,14 @@ static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
 
 /* Loop over all objects in a slab */
 #define for_each_object(__p, __s, __addr, __objects) \
-	for (__p = (__addr); __p < (__addr) + (__objects) * (__s)->size;\
-			__p += (__s)->size)
+	for (__p = fixup_red_left(__s, __addr); \
+		__p < (__addr) + (__objects) * (__s)->size; \
+		__p += (__s)->size)
 
 #define for_each_object_idx(__p, __idx, __s, __addr, __objects) \
-	for (__p = (__addr), __idx = 1; __idx <= __objects;\
-			__p += (__s)->size, __idx++)
+	for (__p = fixup_red_left(__s, __addr), __idx = 1; \
+		__idx <= __objects; \
+		__p += (__s)->size, __idx++)
 
 /* Determine object index from a given position */
 static inline int slab_index(void *p, struct kmem_cache *s, void *addr)
@@ -456,6 +448,22 @@ static void get_map(struct kmem_cache *s, struct page *page, unsigned long *map)
 		set_bit(slab_index(p, s, addr), map);
 }
 
+static inline int size_from_object(struct kmem_cache *s)
+{
+	if (s->flags & SLAB_RED_ZONE)
+		return s->size - s->red_left_pad;
+
+	return s->size;
+}
+
+static inline void *restore_red_left(struct kmem_cache *s, void *p)
+{
+	if (s->flags & SLAB_RED_ZONE)
+		p -= s->red_left_pad;
+
+	return p;
+}
+
 /*
  * Debug settings:
  */
@@ -489,6 +497,26 @@ static inline void metadata_access_disable(void)
 /*
  * Object debugging
  */
+
+/* Verify that a pointer has an address that is valid within a slab page */
+static inline int check_valid_pointer(struct kmem_cache *s,
+				struct page *page, void *object)
+{
+	void *base;
+
+	if (!object)
+		return 1;
+
+	base = page_address(page);
+	object = restore_red_left(s, object);
+	if (object < base || object >= base + page->objects * s->size ||
+		(object - base) % s->size) {
+		return 0;
+	}
+
+	return 1;
+}
+
 static void print_section(char *text, u8 *addr, unsigned int length)
 {
 	metadata_access_enable();
@@ -628,7 +656,9 @@ static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
 	pr_err("INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
 	       p, p - addr, get_freepointer(s, p));
 
-	if (p > addr + 16)
+	if (s->flags & SLAB_RED_ZONE)
+		print_section("Redzone ", p - s->red_left_pad, s->red_left_pad);
+	else if (p > addr + 16)
 		print_section("Bytes b4 ", p - 16, 16);
 
 	print_section("Object ", p, min_t(unsigned long, s->object_size,
@@ -645,9 +675,9 @@ static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
 	if (s->flags & SLAB_STORE_USER)
 		off += 2 * sizeof(struct track);
 
-	if (off != s->size)
+	if (off != size_from_object(s))
 		/* Beginning of the filler is the free pointer */
-		print_section("Padding ", p + off, s->size - off);
+		print_section("Padding ", p + off, size_from_object(s) - off);
 
 	dump_stack();
 }
@@ -677,6 +707,9 @@ static void init_object(struct kmem_cache *s, void *object, u8 val)
 {
 	u8 *p = object;
 
+	if (s->flags & SLAB_RED_ZONE)
+		memset(p - s->red_left_pad, val, s->red_left_pad);
+
 	if (s->flags & __OBJECT_POISON) {
 		memset(p, POISON_FREE, s->object_size - 1);
 		p[s->object_size - 1] = POISON_END;
@@ -769,11 +802,11 @@ static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p)
 		/* We also have user information there */
 		off += 2 * sizeof(struct track);
 
-	if (s->size == off)
+	if (size_from_object(s) == off)
 		return 1;
 
 	return check_bytes_and_report(s, page, p, "Object padding",
-				p + off, POISON_INUSE, s->size - off);
+			p + off, POISON_INUSE, size_from_object(s) - off);
 }
 
 /* Check the pad bytes at the end of a slab page */
@@ -817,6 +850,10 @@ static int check_object(struct kmem_cache *s, struct page *page,
 	u8 *endobject = object + s->object_size;
 
 	if (s->flags & SLAB_RED_ZONE) {
+		if (!check_bytes_and_report(s, page, object, "Redzone",
+			object - s->red_left_pad, val, s->red_left_pad))
+			return 0;
+
 		if (!check_bytes_and_report(s, page, object, "Redzone",
 			endobject, val, s->inuse - s->object_size))
 			return 0;
@@ -1468,7 +1505,7 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
 			set_freepointer(s, p, NULL);
 	}
 
-	page->freelist = start;
+	page->freelist = fixup_red_left(s, start);
 	page->inuse = page->objects;
 	page->frozen = 1;
 
@@ -2819,6 +2856,7 @@ struct detached_freelist {
 	void *tail;
 	void *freelist;
 	int cnt;
+	struct kmem_cache *s;
 };
 
 /*
@@ -2833,8 +2871,9 @@ struct detached_freelist {
  * synchronization primitive.  Look ahead in the array is limited due
  * to performance reasons.
  */
-static int build_detached_freelist(struct kmem_cache *s, size_t size,
-				   void **p, struct detached_freelist *df)
+static inline
+int build_detached_freelist(struct kmem_cache *s, size_t size,
+			    void **p, struct detached_freelist *df)
 {
 	size_t first_skipped_index = 0;
 	int lookahead = 3;
@@ -2850,8 +2889,11 @@ static int build_detached_freelist(struct kmem_cache *s, size_t size,
 	if (!object)
 		return 0;
 
+	/* Support for memcg, compiler can optimize this out */
+	df->s = cache_from_obj(s, object);
+
 	/* Start new detached freelist */
-	set_freepointer(s, object, NULL);
+	set_freepointer(df->s, object, NULL);
 	df->page = virt_to_head_page(object);
 	df->tail = object;
 	df->freelist = object;
@@ -2866,7 +2908,7 @@ static int build_detached_freelist(struct kmem_cache *s, size_t size,
 		/* df->page is always set at this point */
 		if (df->page == virt_to_head_page(object)) {
 			/* Opportunity build freelist */
-			set_freepointer(s, object, df->freelist);
+			set_freepointer(df->s, object, df->freelist);
 			df->freelist = object;
 			df->cnt++;
 			p[size] = NULL; /* mark object processed */
@@ -2885,25 +2927,20 @@ static int build_detached_freelist(struct kmem_cache *s, size_t size,
 	return first_skipped_index;
 }
 
-
 /* Note that interrupts must be enabled when calling this function. */
-void kmem_cache_free_bulk(struct kmem_cache *orig_s, size_t size, void **p)
+void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p)
 {
 	if (WARN_ON(!size))
 		return;
 
 	do {
 		struct detached_freelist df;
-		struct kmem_cache *s;
-
-		/* Support for memcg */
-		s = cache_from_obj(orig_s, p[size - 1]);
 
 		size = build_detached_freelist(s, size, p, &df);
 		if (unlikely(!df.page))
 			continue;
 
-		slab_free(s, df.page, df.freelist, df.tail, df.cnt, _RET_IP_);
+		slab_free(df.s, df.page, df.freelist, df.tail, df.cnt,_RET_IP_);
 	} while (likely(size));
 }
 EXPORT_SYMBOL(kmem_cache_free_bulk);
@@ -3283,7 +3320,7 @@ static int calculate_sizes(struct kmem_cache *s, int forced_order)
 		 */
 		size += 2 * sizeof(struct track);
 
-	if (flags & SLAB_RED_ZONE)
+	if (flags & SLAB_RED_ZONE) {
 		/*
 		 * Add some empty padding so that we can catch
 		 * overwrites from earlier objects rather than let
@@ -3292,6 +3329,11 @@ static int calculate_sizes(struct kmem_cache *s, int forced_order)
 		 * of the object.
 		 */
 		size += sizeof(void *);
+
+		s->red_left_pad = sizeof(void *);
+		s->red_left_pad = ALIGN(s->red_left_pad, s->align);
+		size += s->red_left_pad;
+	}
 #endif
 
 	/*
@@ -3585,6 +3627,46 @@ void *__kmalloc_node(size_t size, gfp_t flags, int node)
 EXPORT_SYMBOL(__kmalloc_node);
 #endif
 
+#ifdef CONFIG_HARDENED_USERCOPY
+/*
+ * Rejects objects that are incorrectly sized.
+ *
+ * Returns NULL if check passes, otherwise const char * to name of cache
+ * to indicate an error.
+ */
+const char *__check_heap_object(const void *ptr, unsigned long n,
+				struct page *page)
+{
+	struct kmem_cache *s;
+	unsigned long offset;
+	size_t object_size;
+
+	/* Find object and usable object size. */
+	s = page->slab_cache;
+	object_size = slab_ksize(s);
+
+	/* Reject impossible pointers. */
+	if (ptr < page_address(page))
+		return s->name;
+
+	/* Find offset within object. */
+	offset = (ptr - page_address(page)) % s->size;
+
+	/* Adjust for redzone and reject if within the redzone. */
+	if (kmem_cache_debug(s) && s->flags & SLAB_RED_ZONE) {
+		if (offset < s->red_left_pad)
+			return s->name;
+		offset -= s->red_left_pad;
+	}
+
+	/* Allow address range falling entirely within object size. */
+	if (offset <= object_size && n <= object_size - offset)
+		return NULL;
+
+	return s->name;
+}
+#endif /* CONFIG_HARDENED_USERCOPY */
+
 static size_t __ksize(const void *object)
 {
 	struct page *page;