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@samsung.com>
Tested-by: David Rientjes <rientjes@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Chernenkov <drcheren@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/mempool.c b/mm/mempool.c
index 2884d5b..2cc08de 100644
--- a/mm/mempool.c
+++ b/mm/mempool.c
@@ -12,6 +12,7 @@
#include <linux/mm.h>
#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 @@
}
#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 @@
BUG_ON(pool->curr_nr < 0);
check_element(pool, element);
+ kasan_unpoison_element(pool, element);
return element;
}