On Wed, Mar 13, 2019 at 8:16 PM Sasha Levin <sashal@xxxxxxxxxx> wrote: > > From: Andrey Konovalov <andreyknvl@xxxxxxxxxx> > > [ Upstream commit 51dedad06b5f6c3eea7ec1069631b1ef7796912a ] Hi Sasha, None of the 4.9, 4.14, 4.19 or 4.20 have tag-based KASAN, so backporting these 3 KASAN related patches doesn't make much sense. Thanks! > > 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@xxxxxxxxxx > Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> > Tested-by: Qian Cai <cai@xxxxxx> > Cc: Alexander Potapenko <glider@xxxxxxxxxx> > Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx> > Cc: Catalin Marinas <catalin.marinas@xxxxxxx> > Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx> > Cc: Evgeniy Stepanov <eugenis@xxxxxxxxxx> > Cc: Kostya Serebryany <kcc@xxxxxxxxxx> > Cc: Vincenzo Frascino <vincenzo.frascino@xxxxxxx> > Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> > --- > mm/slab.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/mm/slab.c b/mm/slab.c > index 409631e49295..766043dd3f8e 100644 > --- a/mm/slab.c > +++ b/mm/slab.c > @@ -2378,6 +2378,7 @@ 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 { > @@ -2690,6 +2691,13 @@ 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); > @@ -2698,7 +2706,6 @@ 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)) > -- > 2.19.1 >
