On Tue, Apr 21, 2020 at 2:26 PM Walter Wu <walter-zh.wu@xxxxxxxxxxxx> wrote: > > Hi Dmitry, > > On Tue, 2020-04-21 at 13:56 +0200, Dmitry Vyukov wrote: > > On Tue, Apr 21, 2020 at 3:40 AM Walter Wu <walter-zh.wu@xxxxxxxxxxxx> wrote: > > > > > > When we use tag-based KASAN, then KASAN unit tests don't detect > > > out-of-bounds memory access. Because with tag-based KASAN the state > > > of each 16 aligned bytes of memory is encoded in one shadow byte > > > and the shadow value is tag of pointer, so we need to read next > > > shadow byte, the shadow value is not equal to tag of pointer, > > > then tag-based KASAN will detect out-of-bounds memory access. > > > > > > Signed-off-by: Walter Wu <walter-zh.wu@xxxxxxxxxxxx> > > > Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx> > > > Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx> > > > Cc: Alexander Potapenko <glider@xxxxxxxxxx> > > > Cc: Matthias Brugger <matthias.bgg@xxxxxxxxx> > > > Cc: Andrey Konovalov <andreyknvl@xxxxxxxxxx> > > > Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > > > --- > > > lib/test_kasan.c | 62 ++++++++++++++++++++++++++++++++++++++++++------ > > > 1 file changed, 55 insertions(+), 7 deletions(-) > > > > > > diff --git a/lib/test_kasan.c b/lib/test_kasan.c > > > index e3087d90e00d..a164f6b47fe5 100644 > > > --- a/lib/test_kasan.c > > > +++ b/lib/test_kasan.c > > > @@ -40,7 +40,12 @@ static noinline void __init kmalloc_oob_right(void) > > > return; > > > } > > > > Hi Walter, > > > > This would be great to have! > > But I am concerned about these series that port KASAN tests to KUNIT: > > https://lkml.org/lkml/2020/4/17/1144 > > I suspect it will be one large merge conflict. Not sure what is the > > proper way to resovle this. I've added authors to CC. > > > Yes, it should have conflicts. Thanks for your reminder. > > > > > +#ifdef CONFIG_KASAN_GENERIC > > > ptr[size] = 'x'; > > > +#else > > > + ptr[size + 5] = 'x'; > > > +#endif > > > + > > > > For this particular snippet I think we can reduce amount of idef'ery > > and amount of non-compiled code in each configuration with something > > like: > > > > ptr[size + 5] = 'x'; > > if (ENABLED(CONFIG_KASAN_GENERIC)) > > ptr[size] = 'x'; > > > > One check runs always (it should pass in both configs, right?). The > > There is a problem, With generic KASAN it may trigger two KASAN reports. Why is this a problem? If there are 2, fine. KUNIT can check that if we expect 2, there are indeed 2. > if we change it like: > > if (ENABLED(CONFIG_KASAN_GENERIC)) > ptr[size] = 'x'; > else > ptr[size + 5] = 'x'; > > > only only in GENERIC, but it's C-level if rather than preprocessor. > > KUNIT should make 2 bugs per test easily expressable (and testable). > > > > > > > > > > > > kfree(ptr); > > > } > > > > > > @@ -92,7 +97,12 @@ static noinline void __init kmalloc_pagealloc_oob_right(void) > > > return; > > > } > > > > > > +#ifdef CONFIG_KASAN_GENERIC > > > ptr[size] = 0; > > > +#else > > > + ptr[size + 6] = 0; > > > +#endif > > > + > > > kfree(ptr); > > > } > > > > > > @@ -162,7 +172,11 @@ static noinline void __init kmalloc_oob_krealloc_more(void) > > > return; > > > } > > > > > > +#ifdef CONFIG_KASAN_GENERIC > > > ptr2[size2] = 'x'; > > > +#else > > > + ptr2[size2 + 13] = 'x'; > > > +#endif > > > kfree(ptr2); > > > } > > > > > > @@ -180,7 +194,12 @@ static noinline void __init kmalloc_oob_krealloc_less(void) > > > kfree(ptr1); > > > return; > > > } > > > + > > > +#ifdef CONFIG_KASAN_GENERIC > > > ptr2[size2] = 'x'; > > > +#else > > > + ptr2[size2 + 2] = 'x'; > > > +#endif > > > kfree(ptr2); > > > } > > > > > > @@ -216,7 +235,11 @@ static noinline void __init kmalloc_oob_memset_2(void) > > > return; > > > } > > > > > > +#ifdef CONFIG_KASAN_GENERIC > > > memset(ptr+7, 0, 2); > > > +#else > > > + memset(ptr+15, 0, 2); > > > +#endif > > > kfree(ptr); > > > } > > > > > > @@ -232,7 +255,11 @@ static noinline void __init kmalloc_oob_memset_4(void) > > > return; > > > } > > > > > > +#ifdef CONFIG_KASAN_GENERIC > > > memset(ptr+5, 0, 4); > > > +#else > > > + memset(ptr+15, 0, 4); > > > +#endif > > > kfree(ptr); > > > } > > > > > > @@ -249,7 +276,11 @@ static noinline void __init kmalloc_oob_memset_8(void) > > > return; > > > } > > > > > > +#ifdef CONFIG_KASAN_GENERIC > > > memset(ptr+1, 0, 8); > > > +#else > > > + memset(ptr+15, 0, 8); > > > +#endif > > > kfree(ptr); > > > } > > > > > > @@ -265,7 +296,11 @@ static noinline void __init kmalloc_oob_memset_16(void) > > > return; > > > } > > > > > > +#ifdef CONFIG_KASAN_GENERIC > > > memset(ptr+1, 0, 16); > > > +#else > > > + memset(ptr+15, 0, 16); > > > +#endif > > > kfree(ptr); > > > } > > > > > > @@ -281,7 +316,11 @@ static noinline void __init kmalloc_oob_in_memset(void) > > > return; > > > } > > > > > > +#ifdef CONFIG_KASAN_GENERIC > > > memset(ptr, 0, size+5); > > > +#else > > > + memset(ptr, 0, size+7); > > > +#endif > > > kfree(ptr); > > > } > > > > > > @@ -415,7 +454,11 @@ static noinline void __init kmem_cache_oob(void) > > > return; > > > } > > > > > > +#ifdef CONFIG_KASAN_GENERIC > > > *p = p[size]; > > > +#else > > > + *p = p[size + 8]; > > > +#endif > > > kmem_cache_free(cache, p); > > > kmem_cache_destroy(cache); > > > } > > > @@ -497,6 +540,11 @@ static noinline void __init copy_user_test(void) > > > char __user *usermem; > > > size_t size = 10; > > > int unused; > > > +#ifdef CONFIG_KASAN_GENERIC > > > + size_t oob_size = 1; > > > +#else > > > + size_t oob_size = 7; > > > +#endif > > > > > > kmem = kmalloc(size, GFP_KERNEL); > > > if (!kmem) > > > @@ -512,25 +560,25 @@ static noinline void __init copy_user_test(void) > > > } > > > > > > pr_info("out-of-bounds in copy_from_user()\n"); > > > - unused = copy_from_user(kmem, usermem, size + 1); > > > + unused = copy_from_user(kmem, usermem, size + oob_size); > > > > > > pr_info("out-of-bounds in copy_to_user()\n"); > > > - unused = copy_to_user(usermem, kmem, size + 1); > > > + unused = copy_to_user(usermem, kmem, size + oob_size); > > > > > > pr_info("out-of-bounds in __copy_from_user()\n"); > > > - unused = __copy_from_user(kmem, usermem, size + 1); > > > + unused = __copy_from_user(kmem, usermem, size + oob_size); > > > > > > pr_info("out-of-bounds in __copy_to_user()\n"); > > > - unused = __copy_to_user(usermem, kmem, size + 1); > > > + unused = __copy_to_user(usermem, kmem, size + oob_size); > > > > > > pr_info("out-of-bounds in __copy_from_user_inatomic()\n"); > > > - unused = __copy_from_user_inatomic(kmem, usermem, size + 1); > > > + unused = __copy_from_user_inatomic(kmem, usermem, size + oob_size); > > > > > > pr_info("out-of-bounds in __copy_to_user_inatomic()\n"); > > > - unused = __copy_to_user_inatomic(usermem, kmem, size + 1); > > > + unused = __copy_to_user_inatomic(usermem, kmem, size + oob_size); > > > > > > pr_info("out-of-bounds in strncpy_from_user()\n"); > > > - unused = strncpy_from_user(kmem, usermem, size + 1); > > > + unused = strncpy_from_user(kmem, usermem, size + oob_size); > > > > > > vm_munmap((unsigned long)usermem, PAGE_SIZE); > > > kfree(kmem); > > > -- > > > 2.18.0 > > > > > > -- > > > 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 view this discussion on the web visit https://groups.google.com/d/msgid/kasan-dev/20200421014007.6012-1-walter-zh.wu%40mediatek.com. > > -- > 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 view this discussion on the web visit https://groups.google.com/d/msgid/kasan-dev/1587472005.5870.7.camel%40mtksdccf07.
