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| author | Dmitry Vyukov <dvyukov@google.com> | 2018-02-07 00:36:23 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-02-07 03:32:42 +0100 |
| commit | 47adccce3e8a31d315f47183ab1185862b2fc5d4 (patch) | |
| tree | aaf982ef67484b702b42440b459cfd648e58dc4e /mm/slub.c | |
| parent | kasan: add functions for unpoisoning stack variables (diff) | |
| download | linux-47adccce3e8a31d315f47183ab1185862b2fc5d4.tar.xz linux-47adccce3e8a31d315f47183ab1185862b2fc5d4.zip | |
kasan: detect invalid frees for large objects
Patch series "kasan: detect invalid frees".
KASAN detects double-frees, but does not detect invalid-frees (when a
pointer into a middle of heap object is passed to free). We recently had
a very unpleasant case in crypto code which freed an inner object inside
of a heap allocation. This left unnoticed during free, but totally
corrupted heap and later lead to a bunch of random crashes all over kernel
code.
Detect invalid frees.
This patch (of 5):
Detect frees of pointers into middle of large heap objects.
I dropped const from kasan_kfree_large() because it starts propagating
through a bunch of functions in kasan_report.c, slab/slub nearest_obj(),
all of their local variables, fixup_red_left(), etc.
Link: http://lkml.kernel.org/r/1b45b4fe1d20fc0de1329aab674c1dd973fee723.1514378558.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 '')
| -rw-r--r-- | mm/slub.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/mm/slub.c b/mm/slub.c index cc71176c6eef..b54f8787c674 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -1356,7 +1356,7 @@ static inline void kmalloc_large_node_hook(void *ptr, size_t size, gfp_t flags) kasan_kmalloc_large(ptr, size, flags); } -static inline void kfree_hook(const void *x) +static inline void kfree_hook(void *x) { kmemleak_free(x); kasan_kfree_large(x); @@ -3910,7 +3910,7 @@ void kfree(const void *x) page = virt_to_head_page(x); if (unlikely(!PageSlab(page))) { BUG_ON(!PageCompound(page)); - kfree_hook(x); + kfree_hook(object); __free_pages(page, compound_order(page)); return; } |