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| author | Andrey Konovalov <andreyknvl@google.com> | 2018-12-28 00:30:50 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-12-28 12:11:44 -0800 |
| commit | 7f94ffbc4c6a1bdb51d39965e4f2acaa19bd798f (patch) | |
| tree | 5b6b2519c9979a3b557a812843d054c91886e441 /mm/kasan/kasan.h | |
| parent | 5b7c4148222d7acaa1612e5eec84fc66c88d54f3 (diff) | |
| download | lwn-7f94ffbc4c6a1bdb51d39965e4f2acaa19bd798f.tar.gz lwn-7f94ffbc4c6a1bdb51d39965e4f2acaa19bd798f.zip | |
kasan: add hooks implementation for tag-based mode
This commit adds tag-based KASAN specific hooks implementation and
adjusts common generic and tag-based KASAN ones.
1. When a new slab cache is created, tag-based KASAN rounds up the size of
the objects in this cache to KASAN_SHADOW_SCALE_SIZE (== 16).
2. On each kmalloc tag-based KASAN generates a random tag, sets the shadow
memory, that corresponds to this object to this tag, and embeds this
tag value into the top byte of the returned pointer.
3. On each kfree tag-based KASAN poisons the shadow memory with a random
tag to allow detection of use-after-free bugs.
The rest of the logic of the hook implementation is very much similar to
the one provided by generic KASAN. Tag-based KASAN saves allocation and
free stack metadata to the slab object the same way generic KASAN does.
Link: http://lkml.kernel.org/r/bda78069e3b8422039794050ddcb2d53d053ed41.1544099024.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/kasan/kasan.h')
| -rw-r--r-- | mm/kasan/kasan.h | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h index 82a23b23ff93..ea51b2d898ec 100644 --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -12,10 +12,18 @@ #define KASAN_TAG_INVALID 0xFE /* inaccessible memory tag */ #define KASAN_TAG_MAX 0xFD /* maximum value for random tags */ +#ifdef CONFIG_KASAN_GENERIC #define KASAN_FREE_PAGE 0xFF /* page was freed */ #define KASAN_PAGE_REDZONE 0xFE /* redzone for kmalloc_large allocations */ #define KASAN_KMALLOC_REDZONE 0xFC /* redzone inside slub object */ #define KASAN_KMALLOC_FREE 0xFB /* object was freed (kmem_cache_free/kfree) */ +#else +#define KASAN_FREE_PAGE KASAN_TAG_INVALID +#define KASAN_PAGE_REDZONE KASAN_TAG_INVALID +#define KASAN_KMALLOC_REDZONE KASAN_TAG_INVALID +#define KASAN_KMALLOC_FREE KASAN_TAG_INVALID +#endif + #define KASAN_GLOBAL_REDZONE 0xFA /* redzone for global variable */ /* |