The patch titled
Subject: kasan: introduce kasan_init_cache_meta
has been added to the -mm mm-unstable branch. Its filename is
kasan-introduce-kasan_init_cache_meta.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/kasan-introduce-kasan_init_cache_meta.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Subject: kasan: introduce kasan_init_cache_meta
Date: Mon, 5 Sep 2022 23:05:27 +0200
Add a kasan_init_cache_meta() helper that initializes metadata-related
cache parameters and use this helper in the common KASAN code.
Put the implementation of this new helper into generic.c, as only the
Generic mode uses per-object metadata.
Link: https://lkml.kernel.org/r/a6d7ea01876eb36472c9879f7b23f1b24766276e.1662411799.git.andreyknvl@xxxxxxxxxx
Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Reviewed-by: Marco Elver <elver@xxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Evgenii Stepanov <eugenis@xxxxxxxxxx>
Cc: Peter Collingbourne <pcc@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/kasan/common.c | 80 +------------------------------------------
mm/kasan/generic.c | 79 ++++++++++++++++++++++++++++++++++++++++++
mm/kasan/kasan.h | 2 +
3 files changed, 83 insertions(+), 78 deletions(-)
--- a/mm/kasan/common.c~kasan-introduce-kasan_init_cache_meta
+++ a/mm/kasan/common.c
@@ -118,28 +118,9 @@ void __kasan_poison_pages(struct page *p
KASAN_PAGE_FREE, init);
}
-/*
- * Adaptive redzone policy taken from the userspace AddressSanitizer runtime.
- * For larger allocations larger redzones are used.
- */
-static inline unsigned int optimal_redzone(unsigned int object_size)
-{
- return
- object_size <= 64 - 16 ? 16 :
- object_size <= 128 - 32 ? 32 :
- object_size <= 512 - 64 ? 64 :
- object_size <= 4096 - 128 ? 128 :
- object_size <= (1 << 14) - 256 ? 256 :
- object_size <= (1 << 15) - 512 ? 512 :
- object_size <= (1 << 16) - 1024 ? 1024 : 2048;
-}
-
void __kasan_cache_create(struct kmem_cache *cache, unsigned int *size,
slab_flags_t *flags)
{
- unsigned int ok_size;
- unsigned int optimal_size;
-
/*
* SLAB_KASAN is used to mark caches as ones that are sanitized by
* KASAN. Currently this flag is used in two places:
@@ -149,65 +130,8 @@ void __kasan_cache_create(struct kmem_ca
*/
*flags |= SLAB_KASAN;
- if (!kasan_requires_meta())
- return;
-
- ok_size = *size;
-
- /* Add alloc meta into redzone. */
- cache->kasan_info.alloc_meta_offset = *size;
- *size += sizeof(struct kasan_alloc_meta);
-
- /*
- * If alloc meta doesn't fit, don't add it.
- * This can only happen with SLAB, as it has KMALLOC_MAX_SIZE equal
- * to KMALLOC_MAX_CACHE_SIZE and doesn't fall back to page_alloc for
- * larger sizes.
- */
- if (*size > KMALLOC_MAX_SIZE) {
- cache->kasan_info.alloc_meta_offset = 0;
- *size = ok_size;
- /* Continue, since free meta might still fit. */
- }
-
- /* Only the generic mode uses free meta or flexible redzones. */
- if (!IS_ENABLED(CONFIG_KASAN_GENERIC)) {
- cache->kasan_info.free_meta_offset = KASAN_NO_FREE_META;
- return;
- }
-
- /*
- * Add free meta into redzone when it's not possible to store
- * it in the object. This is the case when:
- * 1. Object is SLAB_TYPESAFE_BY_RCU, which means that it can
- * be touched after it was freed, or
- * 2. Object has a constructor, which means it's expected to
- * retain its content until the next allocation, or
- * 3. Object is too small.
- * Otherwise cache->kasan_info.free_meta_offset = 0 is implied.
- */
- if ((cache->flags & SLAB_TYPESAFE_BY_RCU) || cache->ctor ||
- cache->object_size < sizeof(struct kasan_free_meta)) {
- ok_size = *size;
-
- cache->kasan_info.free_meta_offset = *size;
- *size += sizeof(struct kasan_free_meta);
-
- /* If free meta doesn't fit, don't add it. */
- if (*size > KMALLOC_MAX_SIZE) {
- cache->kasan_info.free_meta_offset = KASAN_NO_FREE_META;
- *size = ok_size;
- }
- }
-
- /* Calculate size with optimal redzone. */
- optimal_size = cache->object_size + optimal_redzone(cache->object_size);
- /* Limit it with KMALLOC_MAX_SIZE (relevant for SLAB only). */
- if (optimal_size > KMALLOC_MAX_SIZE)
- optimal_size = KMALLOC_MAX_SIZE;
- /* Use optimal size if the size with added metas is not large enough. */
- if (*size < optimal_size)
- *size = optimal_size;
+ if (kasan_requires_meta())
+ kasan_init_cache_meta(cache, size);
}
void __kasan_cache_create_kmalloc(struct kmem_cache *cache)
--- a/mm/kasan/generic.c~kasan-introduce-kasan_init_cache_meta
+++ a/mm/kasan/generic.c
@@ -328,6 +328,85 @@ DEFINE_ASAN_SET_SHADOW(f3);
DEFINE_ASAN_SET_SHADOW(f5);
DEFINE_ASAN_SET_SHADOW(f8);
+/*
+ * Adaptive redzone policy taken from the userspace AddressSanitizer runtime.
+ * For larger allocations larger redzones are used.
+ */
+static inline unsigned int optimal_redzone(unsigned int object_size)
+{
+ return
+ object_size <= 64 - 16 ? 16 :
+ object_size <= 128 - 32 ? 32 :
+ object_size <= 512 - 64 ? 64 :
+ object_size <= 4096 - 128 ? 128 :
+ object_size <= (1 << 14) - 256 ? 256 :
+ object_size <= (1 << 15) - 512 ? 512 :
+ object_size <= (1 << 16) - 1024 ? 1024 : 2048;
+}
+
+void kasan_init_cache_meta(struct kmem_cache *cache, unsigned int *size)
+{
+ unsigned int ok_size;
+ unsigned int optimal_size;
+
+ ok_size = *size;
+
+ /* Add alloc meta into redzone. */
+ cache->kasan_info.alloc_meta_offset = *size;
+ *size += sizeof(struct kasan_alloc_meta);
+
+ /*
+ * If alloc meta doesn't fit, don't add it.
+ * This can only happen with SLAB, as it has KMALLOC_MAX_SIZE equal
+ * to KMALLOC_MAX_CACHE_SIZE and doesn't fall back to page_alloc for
+ * larger sizes.
+ */
+ if (*size > KMALLOC_MAX_SIZE) {
+ cache->kasan_info.alloc_meta_offset = 0;
+ *size = ok_size;
+ /* Continue, since free meta might still fit. */
+ }
+
+ /* Only the generic mode uses free meta or flexible redzones. */
+ if (!IS_ENABLED(CONFIG_KASAN_GENERIC)) {
+ cache->kasan_info.free_meta_offset = KASAN_NO_FREE_META;
+ return;
+ }
+
+ /*
+ * Add free meta into redzone when it's not possible to store
+ * it in the object. This is the case when:
+ * 1. Object is SLAB_TYPESAFE_BY_RCU, which means that it can
+ * be touched after it was freed, or
+ * 2. Object has a constructor, which means it's expected to
+ * retain its content until the next allocation, or
+ * 3. Object is too small.
+ * Otherwise cache->kasan_info.free_meta_offset = 0 is implied.
+ */
+ if ((cache->flags & SLAB_TYPESAFE_BY_RCU) || cache->ctor ||
+ cache->object_size < sizeof(struct kasan_free_meta)) {
+ ok_size = *size;
+
+ cache->kasan_info.free_meta_offset = *size;
+ *size += sizeof(struct kasan_free_meta);
+
+ /* If free meta doesn't fit, don't add it. */
+ if (*size > KMALLOC_MAX_SIZE) {
+ cache->kasan_info.free_meta_offset = KASAN_NO_FREE_META;
+ *size = ok_size;
+ }
+ }
+
+ /* Calculate size with optimal redzone. */
+ optimal_size = cache->object_size + optimal_redzone(cache->object_size);
+ /* Limit it with KMALLOC_MAX_SIZE (relevant for SLAB only). */
+ if (optimal_size > KMALLOC_MAX_SIZE)
+ optimal_size = KMALLOC_MAX_SIZE;
+ /* Use optimal size if the size with added metas is not large enough. */
+ if (*size < optimal_size)
+ *size = optimal_size;
+}
+
struct kasan_alloc_meta *kasan_get_alloc_meta(struct kmem_cache *cache,
const void *object)
{
--- a/mm/kasan/kasan.h~kasan-introduce-kasan_init_cache_meta
+++ a/mm/kasan/kasan.h
@@ -297,12 +297,14 @@ struct page *kasan_addr_to_page(const vo
struct slab *kasan_addr_to_slab(const void *addr);
#ifdef CONFIG_KASAN_GENERIC
+void kasan_init_cache_meta(struct kmem_cache *cache, unsigned int *size);
void kasan_init_object_meta(struct kmem_cache *cache, const void *object);
struct kasan_alloc_meta *kasan_get_alloc_meta(struct kmem_cache *cache,
const void *object);
struct kasan_free_meta *kasan_get_free_meta(struct kmem_cache *cache,
const void *object);
#else
+static inline void kasan_init_cache_meta(struct kmem_cache *cache, unsigned int *size) { }
static inline void kasan_init_object_meta(struct kmem_cache *cache, const void *object) { }
#endif
_
Patches currently in -mm which might be from andreyknvl@xxxxxxxxxx are
kasan-check-kasan_no_free_meta-in-__kasan_metadata_size.patch
kasan-rename-kasan_set__info-to-kasan_save__info.patch
kasan-move-is_kmalloc-check-out-of-save_alloc_info.patch
kasan-split-save_alloc_info-implementations.patch
kasan-drop-config_kasan_tags_identify.patch
kasan-introduce-kasan_print_aux_stacks.patch
kasan-introduce-kasan_get_alloc_track.patch
kasan-introduce-kasan_init_object_meta.patch
kasan-clear-metadata-functions-for-tag-based-modes.patch
kasan-move-kasan_get__meta-to-genericc.patch
kasan-introduce-kasan_requires_meta.patch
kasan-introduce-kasan_init_cache_meta.patch
kasan-drop-config_kasan_generic-check-from-kasan_init_cache_meta.patch
kasan-only-define-kasan_metadata_size-for-generic-mode.patch
kasan-only-define-kasan_never_merge-for-generic-mode.patch
kasan-only-define-metadata-offsets-for-generic-mode.patch
kasan-only-define-metadata-structs-for-generic-mode.patch
kasan-only-define-kasan_cache_create-for-generic-mode.patch
kasan-pass-tagged-pointers-to-kasan_save_alloc-free_info.patch
kasan-move-kasan_get_alloc-free_track-definitions.patch
kasan-cosmetic-changes-in-reportc.patch
kasan-use-virt_addr_valid-in-kasan_addr_to_page-slab.patch
kasan-use-kasan_addr_to_slab-in-print_address_description.patch
kasan-make-kasan_addr_to_page-static.patch
kasan-simplify-print_report.patch
kasan-introduce-complete_report_info.patch
kasan-fill-in-cache-and-object-in-complete_report_info.patch
kasan-rework-function-arguments-in-reportc.patch
kasan-introduce-kasan_complete_mode_report_info.patch
kasan-implement-stack-ring-for-tag-based-modes.patch
kasan-support-kasanstacktrace-for-sw_tags.patch
kasan-dynamically-allocate-stack-ring-entries.patch
kasan-better-identify-bug-types-for-tag-based-modes.patch
kasan-add-another-use-after-free-test.patch
kasan-move-tests-to-mm-kasan.patch
