diff options
author | Dmitry Vyukov <dvyukov@google.com> | 2018-01-05 13:26:04 +1100 |
---|---|---|
committer | Stephen Rothwell <sfr@canb.auug.org.au> | 2018-01-07 02:17:11 +1100 |
commit | 0da214e406fe3c8bdf0f490a5ddb4142403d4a0e (patch) | |
tree | e47b501f529da4853c1f25f63504ea4c550f1276 /mm | |
parent | cd2a878d5b87592c9c172a182ae65cf0512d8479 (diff) |
kasan: detect invalid frees for large mempool objects
Detect frees of pointers into middle of mempool objects.
I did a one-off test, but it turned out to be very tricky, so I reverted
it. First, mempool does not call kasan_poison_kfree() unless allocation
function fails. I stubbed an allocation function to fail on second and
subsequent allocations. But then mempool stopped to call
kasan_poison_kfree() at all, because it does it only when allocation
function is mempool_kmalloc(). We could support this special failing test
allocation function in mempool, but it also can't live with kasan tests,
because these are in a module.
Link: http://lkml.kernel.org/r/bf7a7d035d7a5ed62d2dd0e3d2e8a4fcdf456aa7.1514378558.git.dvyukov@google.com
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>a
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Diffstat (limited to 'mm')
-rw-r--r-- | mm/kasan/kasan.c | 11 | ||||
-rw-r--r-- | mm/mempool.c | 6 |
2 files changed, 11 insertions, 6 deletions
diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c index 047226ff220b..f8f741300d71 100644 --- a/mm/kasan/kasan.c +++ b/mm/kasan/kasan.c @@ -588,17 +588,22 @@ void kasan_krealloc(const void *object, size_t size, gfp_t flags) kasan_kmalloc(page->slab_cache, object, size, flags); } -void kasan_poison_kfree(void *ptr) +void kasan_poison_kfree(void *ptr, unsigned long ip) { struct page *page; page = virt_to_head_page(ptr); - if (unlikely(!PageSlab(page))) + if (unlikely(!PageSlab(page))) { + if (ptr != page_address(page)) { + kasan_report_invalid_free(ptr, ip); + return; + } kasan_poison_shadow(ptr, PAGE_SIZE << compound_order(page), KASAN_FREE_PAGE); - else + } else { kasan_poison_slab_free(page->slab_cache, ptr); + } } void kasan_kfree_large(void *ptr, unsigned long ip) diff --git a/mm/mempool.c b/mm/mempool.c index 7d8c5a0010a2..5c9dce34719b 100644 --- a/mm/mempool.c +++ b/mm/mempool.c @@ -103,10 +103,10 @@ 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) +static __always_inline void kasan_poison_element(mempool_t *pool, void *element) { if (pool->alloc == mempool_alloc_slab || pool->alloc == mempool_kmalloc) - kasan_poison_kfree(element); + kasan_poison_kfree(element, _RET_IP_); if (pool->alloc == mempool_alloc_pages) kasan_free_pages(element, (unsigned long)pool->pool_data); } @@ -119,7 +119,7 @@ static void kasan_unpoison_element(mempool_t *pool, void *element, gfp_t flags) kasan_alloc_pages(element, (unsigned long)pool->pool_data); } -static void add_element(mempool_t *pool, void *element) +static __always_inline void add_element(mempool_t *pool, void *element) { BUG_ON(pool->curr_nr >= pool->min_nr); poison_element(pool, element); |