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| author | Andrey Konovalov <andreyknvl@google.com> | 2019-02-21 07:20:28 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-02-21 18:01:00 +0100 |
| commit | 51dedad06b5f6c3eea7ec1069631b1ef7796912a (patch) | |
| tree | f98818f9d27bb7bcc606d6a610291d12fdeda720 | |
| parent | kasan, slab: fix conflicts with CONFIG_HARDENED_USERCOPY (diff) | |
| download | linux-51dedad06b5f6c3eea7ec1069631b1ef7796912a.tar.xz linux-51dedad06b5f6c3eea7ec1069631b1ef7796912a.zip | |
kasan, slab: make freelist stored without tags
Similarly to "kasan, slub: move kasan_poison_slab hook before
page_address", move kasan_poison_slab() before alloc_slabmgmt(), which
calls page_address(), to make page_address() return value to be
non-tagged. This, combined with calling kasan_reset_tag() for off-slab
slab management object, leads to freelist being stored non-tagged.
Link: http://lkml.kernel.org/r/dfb53b44a4d00de3879a05a9f04c1f55e584f7a1.1550602886.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Tested-by: Qian Cai <cai@lca.pw>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgeniy Stepanov <eugenis@google.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/slab.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/mm/slab.c b/mm/slab.c index c84458281a88..4ad95fcb1686 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -2359,7 +2359,7 @@ static void *alloc_slabmgmt(struct kmem_cache *cachep, void *freelist; void *addr = page_address(page); - page->s_mem = kasan_reset_tag(addr) + colour_off; + page->s_mem = addr + colour_off; page->active = 0; if (OBJFREELIST_SLAB(cachep)) @@ -2368,6 +2368,7 @@ static void *alloc_slabmgmt(struct kmem_cache *cachep, /* Slab management obj is off-slab. */ freelist = kmem_cache_alloc_node(cachep->freelist_cache, local_flags, nodeid); + freelist = kasan_reset_tag(freelist); if (!freelist) return NULL; } else { @@ -2681,6 +2682,13 @@ static struct page *cache_grow_begin(struct kmem_cache *cachep, offset *= cachep->colour_off; + /* + * Call kasan_poison_slab() before calling alloc_slabmgmt(), so + * page_address() in the latter returns a non-tagged pointer, + * as it should be for slab pages. + */ + kasan_poison_slab(page); + /* Get slab management. */ freelist = alloc_slabmgmt(cachep, page, offset, local_flags & ~GFP_CONSTRAINT_MASK, page_node); @@ -2689,7 +2697,6 @@ static struct page *cache_grow_begin(struct kmem_cache *cachep, slab_map_pages(cachep, page, freelist); - kasan_poison_slab(page); cache_init_objs(cachep, page); if (gfpflags_allow_blocking(local_flags)) |