From b1d5728939ebe01a773a75a72e7161408ec9805e Mon Sep 17 00:00:00 2001 From: Dmitry Vyukov Date: Tue, 6 Feb 2018 15:36:37 -0800 Subject: kasan: detect invalid frees Detect frees of pointers into middle of heap objects. Link: http://lkml.kernel.org/r/cb569193190356beb018a03bb8d6fbae67e7adbc.1514378558.git.dvyukov@google.com Signed-off-by: Dmitry Vyukov Cc: Andrey Ryabinin a Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/kasan/kasan.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'mm/kasan') diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c index 578843f..3fb497d 100644 --- a/mm/kasan/kasan.c +++ b/mm/kasan/kasan.c @@ -495,6 +495,12 @@ static bool __kasan_slab_free(struct kmem_cache *cache, void *object, s8 shadow_byte; unsigned long rounded_up_size; + if (unlikely(nearest_obj(cache, virt_to_head_page(object), object) != + object)) { + kasan_report_invalid_free(object, ip); + return true; + } + /* RCU slabs could be legally used after free within the RCU period */ if (unlikely(cache->flags & SLAB_TYPESAFE_BY_RCU)) return false; -- cgit v1.1