On Tue, Dec 11, 2018 at 5:22 PM Vincenzo Frascino <vincenzo.frascino@xxxxxxx> wrote: > > Hi Andrey, > > On 06/12/2018 12:24, Andrey Konovalov wrote: > > 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. > > > > Reviewed-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx> > > Reviewed-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx> > > Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> > > --- > > mm/kasan/common.c | 116 ++++++++++++++++++++++++++++++++++++++-------- > > mm/kasan/kasan.h | 8 ++++ > > mm/kasan/tags.c | 48 +++++++++++++++++++ > > 3 files changed, 153 insertions(+), 19 deletions(-) > > > > > [...] > > > @@ -265,6 +290,8 @@ void kasan_cache_create(struct kmem_cache *cache, unsigned int *size, > > return; > > } > > > > + cache->align = round_up(cache->align, KASAN_SHADOW_SCALE_SIZE); > > + > > Did you consider to set ARCH_SLAB_MINALIGN instead of this round up? I didn't know about this macro. Looks like we can use it to do the same thing. Do you think it's a better solution to redefine ARCH_SLAB_MINALIGN to KASAN_SHADOW_SCALE_SIZE for arm64 when tag-based KASAN is enabled instead of adjusting cache->align in kasan_cache_create? > > -- > Regards, > Vincenzo > > -- > You received this message because you are subscribed to the Google Groups "kasan-dev" group. > To unsubscribe from this group and stop receiving emails from it, send an email to kasan-dev+unsubscribe@xxxxxxxxxxxxxxxx. > To post to this group, send email to kasan-dev@xxxxxxxxxxxxxxxx. > To view this discussion on the web visit https://groups.google.com/d/msgid/kasan-dev/2bf7415e-2724-b3c3-9571-20c8b6d43b92%40arm.com. > For more options, visit https://groups.google.com/d/optout.
