The patch titled
Subject: mm/mempool.c: kasan: poison mempool elements
has been added to the -mm tree. Its filename is
mm-mempool-kasan-poison-mempool-elements.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-mempool-kasan-poison-mempool-elements.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-mempool-kasan-poison-mempool-elements.patch
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------------------------------------------------------
From: Andrey Ryabinin <a.ryabinin@xxxxxxxxxxx>
Subject: mm/mempool.c: kasan: poison mempool elements
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 <a.ryabinin@xxxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Dmitry Chernenkov <drcheren@xxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/kasan.h | 2 ++
mm/kasan/kasan.c | 13 +++++++++++++
mm/mempool.c | 23 +++++++++++++++++++++++
3 files changed, 38 insertions(+)
diff -puN include/linux/kasan.h~mm-mempool-kasan-poison-mempool-elements include/linux/kasan.h
--- a/include/linux/kasan.h~mm-mempool-kasan-poison-mempool-elements
+++ a/include/linux/kasan.h
@@ -44,6 +44,7 @@ void kasan_poison_object_data(struct kme
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_d
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 -puN mm/kasan/kasan.c~mm-mempool-kasan-poison-mempool-elements mm/kasan/kasan.c
--- a/mm/kasan/kasan.c~mm-mempool-kasan-poison-mempool-elements
+++ a/mm/kasan/kasan.c
@@ -389,6 +389,19 @@ void kasan_krealloc(const void *object,
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 -puN mm/mempool.c~mm-mempool-kasan-poison-mempool-elements mm/mempool.c
--- a/mm/mempool.c~mm-mempool-kasan-poison-mempool-elements
+++ a/mm/mempool.c
@@ -11,6 +11,7 @@
#include <linux/mm.h>
#include <linux/slab.h>
+#include <linux/kasan.h>
#include <linux/kmemleak.h>
#include <linux/export.h>
#include <linux/mempool.h>
@@ -100,10 +101,31 @@ static inline void poison_element(mempoo
}
#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;
}
@@ -113,6 +135,7 @@ static void *remove_element(mempool_t *p
BUG_ON(pool->curr_nr < 0);
check_element(pool, element);
+ kasan_unpoison_element(pool, element);
return element;
}
_
Patches currently in -mm which might be from a.ryabinin@xxxxxxxxxxx are
arm-factor-out-mmap-aslr-into-mmap_rnd.patch
mm-expose-arch_mmap_rnd-when-available.patch
mm-split-et_dyn-aslr-from-mmap-aslr.patch
mm-fold-arch_randomize_brk-into-arch_has_elf_randomize.patch
mm-mempool-poison-elements-backed-by-page-allocator-fix-fix.patch
mm-mempool-kasan-poison-mempool-elements.patch
gcov-fix-softlockups.patch
linux-next.patch
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