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| author | Dmitry Vyukov <dvyukov@google.com> | 2018-02-06 15:36:30 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-02-06 18:32:43 -0800 |
| commit | 6860f6340c0918cddcd3c9fcf8c36401c8184268 (patch) | |
| tree | 59b652f61341d35394d745a3010bb437a54d6421 /mm/kasan | |
| parent | ee3ce779b58c31acacdfab0ad6c86d428ba2c2e3 (diff) | |
| download | linux-6860f6340c0918cddcd3c9fcf8c36401c8184268.tar.bz2 | |
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: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/kasan')
| -rw-r--r-- | mm/kasan/kasan.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c index 32f555ded938..77c103748728 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) |