| Message ID | 427d46e86c81f3ec77147b0ade4bd551d878cf7a.1605046192.git.andreyknvl@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | kasan: add hardware tag-based mode for arm64 | expand |
On Tue, Nov 10, 2020 at 11:11 PM Andrey Konovalov <andreyknvl@google.com> wrote: > > This is a preparatory commit for the upcoming addition of a new hardware > tag-based (MTE-based) KASAN mode. > > For software KASAN modes the check is based on the value in the shadow > memory. Hardware tag-based KASAN won't be using shadow, so hide the > implementation of the check in check_invalid_free(). > > Also simplify the code for software tag-based mode. > > No functional changes for software modes. > > Signed-off-by: Andrey Konovalov <andreyknvl@google.com> > Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> > Reviewed-by: Marco Elver <elver@google.com> Reviewed-by: Alexander Potapenko <glider@google.com> > --- > Change-Id: I5fae9531c9fc948eb4d4e0c589744032fc5a0789 > --- > mm/kasan/common.c | 19 +------------------ > mm/kasan/generic.c | 7 +++++++ > mm/kasan/kasan.h | 2 ++ > mm/kasan/sw_tags.c | 9 +++++++++ > 4 files changed, 19 insertions(+), 18 deletions(-) > > diff --git a/mm/kasan/common.c b/mm/kasan/common.c > index 123abfb760d4..543e6bf2168f 100644 > --- a/mm/kasan/common.c > +++ b/mm/kasan/common.c > @@ -272,25 +272,9 @@ void * __must_check kasan_init_slab_obj(struct kmem_cache *cache, > return (void *)object; > } > > -static inline bool shadow_invalid(u8 tag, s8 shadow_byte) > -{ > - if (IS_ENABLED(CONFIG_KASAN_GENERIC)) > - return shadow_byte < 0 || > - shadow_byte >= KASAN_GRANULE_SIZE; > - > - /* else CONFIG_KASAN_SW_TAGS: */ > - if ((u8)shadow_byte == KASAN_TAG_INVALID) > - return true; > - if ((tag != KASAN_TAG_KERNEL) && (tag != (u8)shadow_byte)) > - return true; > - > - return false; > -} > - > static bool __kasan_slab_free(struct kmem_cache *cache, void *object, > unsigned long ip, bool quarantine) > { > - s8 shadow_byte; > u8 tag; > void *tagged_object; > unsigned long rounded_up_size; > @@ -309,8 +293,7 @@ static bool __kasan_slab_free(struct kmem_cache *cache, void *object, > if (unlikely(cache->flags & SLAB_TYPESAFE_BY_RCU)) > return false; > > - shadow_byte = READ_ONCE(*(s8 *)kasan_mem_to_shadow(object)); > - if (shadow_invalid(tag, shadow_byte)) { > + if (check_invalid_free(tagged_object)) { > kasan_report_invalid_free(tagged_object, ip); > return true; > } > diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c > index ec4417156943..e1af3b6c53b8 100644 > --- a/mm/kasan/generic.c > +++ b/mm/kasan/generic.c > @@ -187,6 +187,13 @@ bool check_memory_region(unsigned long addr, size_t size, bool write, > return check_memory_region_inline(addr, size, write, ret_ip); > } > > +bool check_invalid_free(void *addr) > +{ > + s8 shadow_byte = READ_ONCE(*(s8 *)kasan_mem_to_shadow(addr)); > + > + return shadow_byte < 0 || shadow_byte >= KASAN_GRANULE_SIZE; > +} > + > void kasan_cache_shrink(struct kmem_cache *cache) > { > quarantine_remove_cache(cache); > diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h > index 1865bb92d47a..3eff57e71ff5 100644 > --- a/mm/kasan/kasan.h > +++ b/mm/kasan/kasan.h > @@ -164,6 +164,8 @@ void kasan_poison_memory(const void *address, size_t size, u8 value); > bool check_memory_region(unsigned long addr, size_t size, bool write, > unsigned long ret_ip); > > +bool check_invalid_free(void *addr); > + > void *find_first_bad_addr(void *addr, size_t size); > const char *get_bug_type(struct kasan_access_info *info); > > diff --git a/mm/kasan/sw_tags.c b/mm/kasan/sw_tags.c > index 4bdd7dbd6647..b2638c2cd58a 100644 > --- a/mm/kasan/sw_tags.c > +++ b/mm/kasan/sw_tags.c > @@ -121,6 +121,15 @@ bool check_memory_region(unsigned long addr, size_t size, bool write, > return true; > } > > +bool check_invalid_free(void *addr) > +{ > + u8 tag = get_tag(addr); > + u8 shadow_byte = READ_ONCE(*(u8 *)kasan_mem_to_shadow(reset_tag(addr))); > + > + return (shadow_byte == KASAN_TAG_INVALID) || > + (tag != KASAN_TAG_KERNEL && tag != shadow_byte); > +} > + > #define DEFINE_HWASAN_LOAD_STORE(size) \ > void __hwasan_load##size##_noabort(unsigned long addr) \ > { \ > -- > 2.29.2.222.g5d2a92d10f8-goog >
diff --git a/mm/kasan/common.c b/mm/kasan/common.c index 123abfb760d4..543e6bf2168f 100644 --- a/mm/kasan/common.c +++ b/mm/kasan/common.c @@ -272,25 +272,9 @@ void * __must_check kasan_init_slab_obj(struct kmem_cache *cache, return (void *)object; } -static inline bool shadow_invalid(u8 tag, s8 shadow_byte) -{ - if (IS_ENABLED(CONFIG_KASAN_GENERIC)) - return shadow_byte < 0 || - shadow_byte >= KASAN_GRANULE_SIZE; - - /* else CONFIG_KASAN_SW_TAGS: */ - if ((u8)shadow_byte == KASAN_TAG_INVALID) - return true; - if ((tag != KASAN_TAG_KERNEL) && (tag != (u8)shadow_byte)) - return true; - - return false; -} - static bool __kasan_slab_free(struct kmem_cache *cache, void *object, unsigned long ip, bool quarantine) { - s8 shadow_byte; u8 tag; void *tagged_object; unsigned long rounded_up_size; @@ -309,8 +293,7 @@ static bool __kasan_slab_free(struct kmem_cache *cache, void *object, if (unlikely(cache->flags & SLAB_TYPESAFE_BY_RCU)) return false; - shadow_byte = READ_ONCE(*(s8 *)kasan_mem_to_shadow(object)); - if (shadow_invalid(tag, shadow_byte)) { + if (check_invalid_free(tagged_object)) { kasan_report_invalid_free(tagged_object, ip); return true; } diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c index ec4417156943..e1af3b6c53b8 100644 --- a/mm/kasan/generic.c +++ b/mm/kasan/generic.c @@ -187,6 +187,13 @@ bool check_memory_region(unsigned long addr, size_t size, bool write, return check_memory_region_inline(addr, size, write, ret_ip); } +bool check_invalid_free(void *addr) +{ + s8 shadow_byte = READ_ONCE(*(s8 *)kasan_mem_to_shadow(addr)); + + return shadow_byte < 0 || shadow_byte >= KASAN_GRANULE_SIZE; +} + void kasan_cache_shrink(struct kmem_cache *cache) { quarantine_remove_cache(cache); diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h index 1865bb92d47a..3eff57e71ff5 100644 --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -164,6 +164,8 @@ void kasan_poison_memory(const void *address, size_t size, u8 value); bool check_memory_region(unsigned long addr, size_t size, bool write, unsigned long ret_ip); +bool check_invalid_free(void *addr); + void *find_first_bad_addr(void *addr, size_t size); const char *get_bug_type(struct kasan_access_info *info); diff --git a/mm/kasan/sw_tags.c b/mm/kasan/sw_tags.c index 4bdd7dbd6647..b2638c2cd58a 100644 --- a/mm/kasan/sw_tags.c +++ b/mm/kasan/sw_tags.c @@ -121,6 +121,15 @@ bool check_memory_region(unsigned long addr, size_t size, bool write, return true; } +bool check_invalid_free(void *addr) +{ + u8 tag = get_tag(addr); + u8 shadow_byte = READ_ONCE(*(u8 *)kasan_mem_to_shadow(reset_tag(addr))); + + return (shadow_byte == KASAN_TAG_INVALID) || + (tag != KASAN_TAG_KERNEL && tag != shadow_byte); +} + #define DEFINE_HWASAN_LOAD_STORE(size) \ void __hwasan_load##size##_noabort(unsigned long addr) \ { \