The commit is pushed to "branch-rh7-3.10.0-229.7.2-ovz" and will appear at
https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-229.7.2.vz7.6.6
------>
commit 185298f11666838595fb5a2574231e5248178256
Author: Andrey Ryabinin <[email protected]>
Date: Thu Sep 3 19:27:48 2015 +0400
ms/mm/mempool.c: kasan: poison mempool elements
https://jira.sw.ru/browse/PSBM-26429
From: Andrey Ryabinin <[email protected]>
commit 923936157b158f36bd6a3d86496dce82b1a957de upstream.
Mempools keep allocated objects in reserved for situations when ordinary
allocation may not be possible to satisfy. These objects shouldn't be
accessed before they leave the pool.
This patch poison elements when get into the pool and unpoison when they
leave it. This will let KASan to detect use-after-free of mempool's
elements.
Signed-off-by: Andrey Ryabinin <[email protected]>
Tested-by: David Rientjes <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Dmitry Chernenkov <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Andrey Ryabinin <[email protected]>
Signed-off-by: Andrey Ryabinin <[email protected]>
---
include/linux/kasan.h | 2 ++
mm/kasan/kasan.c | 13 +++++++++++++
mm/mempool.c | 23 +++++++++++++++++++++++
3 files changed, 38 insertions(+)
diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index 5bb0744..5486d77 100644
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -44,6 +44,7 @@ void kasan_poison_object_data(struct kmem_cache *cache, void
*object);
void kasan_kmalloc_large(const void *ptr, size_t size);
void kasan_kfree_large(const void *ptr);
+void kasan_kfree(void *ptr);
void kasan_kmalloc(struct kmem_cache *s, const void *object, size_t size);
void kasan_krealloc(const void *object, size_t new_size);
@@ -71,6 +72,7 @@ static inline void kasan_poison_object_data(struct kmem_cache
*cache,
static inline void kasan_kmalloc_large(void *ptr, size_t size) {}
static inline void kasan_kfree_large(const void *ptr) {}
+static inline void kasan_kfree(void *ptr) {}
static inline void kasan_kmalloc(struct kmem_cache *s, const void *object,
size_t size) {}
static inline void kasan_krealloc(const void *object, size_t new_size) {}
diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c
index 936d816..6c513a6 100644
--- a/mm/kasan/kasan.c
+++ b/mm/kasan/kasan.c
@@ -389,6 +389,19 @@ void kasan_krealloc(const void *object, size_t size)
kasan_kmalloc(page->slab_cache, object, size);
}
+void kasan_kfree(void *ptr)
+{
+ struct page *page;
+
+ page = virt_to_head_page(ptr);
+
+ if (unlikely(!PageSlab(page)))
+ kasan_poison_shadow(ptr, PAGE_SIZE << compound_order(page),
+ KASAN_FREE_PAGE);
+ else
+ kasan_slab_free(page->slab_cache, ptr);
+}
+
void kasan_kfree_large(const void *ptr)
{
struct page *page = virt_to_page(ptr);
diff --git a/mm/mempool.c b/mm/mempool.c
index db146ad..abf8243 100644
--- a/mm/mempool.c
+++ b/mm/mempool.c
@@ -13,6 +13,7 @@
#include <linux/slab.h>
#include <linux/highmem.h>
+#include <linux/kasan.h>
#include <linux/kmemleak.h>
#include <linux/export.h>
#include <linux/mempool.h>
@@ -101,10 +102,31 @@ static inline void poison_element(mempool_t *pool, void
*element)
}
#endif /* CONFIG_DEBUG_SLAB || CONFIG_SLUB_DEBUG_ON */
+static void kasan_poison_element(mempool_t *pool, void *element)
+{
+ if (pool->alloc == mempool_alloc_slab)
+ kasan_slab_free(pool->pool_data, element);
+ if (pool->alloc == mempool_kmalloc)
+ kasan_kfree(element);
+ if (pool->alloc == mempool_alloc_pages)
+ kasan_free_pages(element, (unsigned long)pool->pool_data);
+}
+
+static void kasan_unpoison_element(mempool_t *pool, void *element)
+{
+ if (pool->alloc == mempool_alloc_slab)
+ kasan_slab_alloc(pool->pool_data, element);
+ if (pool->alloc == mempool_kmalloc)
+ kasan_krealloc(element, (size_t)pool->pool_data);
+ if (pool->alloc == mempool_alloc_pages)
+ kasan_alloc_pages(element, (unsigned long)pool->pool_data);
+}
+
static void add_element(mempool_t *pool, void *element)
{
BUG_ON(pool->curr_nr >= pool->min_nr);
poison_element(pool, element);
+ kasan_poison_element(pool, element);
pool->elements[pool->curr_nr++] = element;
}
@@ -114,6 +136,7 @@ static void *remove_element(mempool_t *pool)
BUG_ON(pool->curr_nr < 0);
check_element(pool, element);
+ kasan_unpoison_element(pool, element);
return element;
}
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