The patch titled
Subject: kasan: unify large kfree checks
has been added to the -mm tree. Its filename is
kasan-unify-large-kfree-checks.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/kasan-unify-large-kfree-checks.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/kasan-unify-large-kfree-checks.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Subject: kasan: unify large kfree checks
Unify checks in kasan_kfree_large() and in kasan_slab_free_mempool() for
large allocations as it's done for small kfree() allocations.
With this change, kasan_slab_free_mempool() starts checking that the first
byte of the memory that's being freed is accessible.
Link: https://lkml.kernel.org/r/dbef8131b70766f8d798d24bb1ab9ae75dadea61.1612208222.git.andreyknvl@xxxxxxxxxx
Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Branislav Rankov <Branislav.Rankov@xxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Evgenii Stepanov <eugenis@xxxxxxxxxx>
Cc: Kevin Brodsky <kevin.brodsky@xxxxxxx>
Cc: Marco Elver <elver@xxxxxxxxxx>
Cc: Peter Collingbourne <pcc@xxxxxxxxxx>
Cc: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/kasan.h | 16 ++++++++--------
mm/kasan/common.c | 36 ++++++++++++++++++++++++++----------
2 files changed, 34 insertions(+), 18 deletions(-)
--- a/include/linux/kasan.h~kasan-unify-large-kfree-checks
+++ a/include/linux/kasan.h
@@ -200,6 +200,13 @@ static __always_inline bool kasan_slab_f
return false;
}
+void __kasan_kfree_large(void *ptr, unsigned long ip);
+static __always_inline void kasan_kfree_large(void *ptr)
+{
+ if (kasan_enabled())
+ __kasan_kfree_large(ptr, _RET_IP_);
+}
+
void __kasan_slab_free_mempool(void *ptr, unsigned long ip);
static __always_inline void kasan_slab_free_mempool(void *ptr)
{
@@ -247,13 +254,6 @@ static __always_inline void * __must_che
return (void *)object;
}
-void __kasan_kfree_large(void *ptr, unsigned long ip);
-static __always_inline void kasan_kfree_large(void *ptr)
-{
- if (kasan_enabled())
- __kasan_kfree_large(ptr, _RET_IP_);
-}
-
/*
* Unlike kasan_check_read/write(), kasan_check_byte() is performed even for
* the hardware tag-based mode that doesn't rely on compiler instrumentation.
@@ -302,6 +302,7 @@ static inline bool kasan_slab_free(struc
{
return false;
}
+static inline void kasan_kfree_large(void *ptr) {}
static inline void kasan_slab_free_mempool(void *ptr) {}
static inline void *kasan_slab_alloc(struct kmem_cache *s, void *object,
gfp_t flags)
@@ -322,7 +323,6 @@ static inline void *kasan_krealloc(const
{
return (void *)object;
}
-static inline void kasan_kfree_large(void *ptr) {}
static inline bool kasan_check_byte(const void *address)
{
return true;
--- a/mm/kasan/common.c~kasan-unify-large-kfree-checks
+++ a/mm/kasan/common.c
@@ -364,6 +364,31 @@ bool __kasan_slab_free(struct kmem_cache
return ____kasan_slab_free(cache, object, ip, true);
}
+static bool ____kasan_kfree_large(void *ptr, unsigned long ip)
+{
+ if (ptr != page_address(virt_to_head_page(ptr))) {
+ kasan_report_invalid_free(ptr, ip);
+ return true;
+ }
+
+ if (!kasan_byte_accessible(ptr)) {
+ kasan_report_invalid_free(ptr, ip);
+ return true;
+ }
+
+ /*
+ * The object will be poisoned by kasan_free_pages() or
+ * kasan_slab_free_mempool().
+ */
+
+ return false;
+}
+
+void __kasan_kfree_large(void *ptr, unsigned long ip)
+{
+ ____kasan_kfree_large(ptr, ip);
+}
+
void __kasan_slab_free_mempool(void *ptr, unsigned long ip)
{
struct page *page;
@@ -377,10 +402,8 @@ void __kasan_slab_free_mempool(void *ptr
* KMALLOC_MAX_SIZE, and kmalloc falls back onto page_alloc.
*/
if (unlikely(!PageSlab(page))) {
- if (ptr != page_address(page)) {
- kasan_report_invalid_free(ptr, ip);
+ if (____kasan_kfree_large(ptr, ip))
return;
- }
kasan_poison(ptr, page_size(page), KASAN_FREE_PAGE);
} else {
____kasan_slab_free(page->slab_cache, ptr, ip, false);
@@ -539,13 +562,6 @@ void * __must_check __kasan_krealloc(con
return ____kasan_kmalloc(page->slab_cache, object, size, flags);
}
-void __kasan_kfree_large(void *ptr, unsigned long ip)
-{
- if (ptr != page_address(virt_to_head_page(ptr)))
- kasan_report_invalid_free(ptr, ip);
- /* The object will be poisoned by kasan_free_pages(). */
-}
-
bool __kasan_check_byte(const void *address, unsigned long ip)
{
if (!kasan_byte_accessible(address)) {
_
Patches currently in -mm which might be from andreyknvl@xxxxxxxxxx are
kasan-prefix-global-functions-with-kasan_.patch
kasan-clarify-hw_tags-impact-on-tbi.patch
kasan-clean-up-comments-in-tests.patch
kasan-add-macros-to-simplify-checking-test-constraints.patch
kasan-add-match-all-tag-tests.patch
kasan-arm64-allow-using-kunit-tests-with-hw_tags-mode.patch
kasan-rename-config_test_kasan_module.patch
kasan-add-compiler-barriers-to-kunit_expect_kasan_fail.patch
kasan-adapt-kmalloc_uaf2-test-to-hw_tags-mode.patch
kasan-fix-memory-corruption-in-kasan_bitops_tags-test.patch
kasan-move-_ret_ip_-to-inline-wrappers.patch
kasan-fix-bug-detection-via-ksize-for-hw_tags-mode.patch
kasan-add-proper-page-allocator-tests.patch
kasan-add-a-test-for-kmem_cache_alloc-free_bulk.patch
kasan-dont-run-tests-when-kasan-is-not-enabled.patch
kasan-mm-dont-save-alloc-stacks-twice.patch
kasan-mm-optimize-kmalloc-poisoning.patch
kasan-optimize-large-kmalloc-poisoning.patch
kasan-clean-up-setting-free-info-in-kasan_slab_free.patch
kasan-unify-large-kfree-checks.patch
kasan-rework-krealloc-tests.patch
kasan-mm-remove-krealloc-side-effect.patch
kasan-mm-optimize-krealloc-poisoning.patch
kasan-ensure-poisoning-size-alignment.patch
arm64-kasan-simplify-and-inline-mte-functions.patch
kasan-always-inline-hw_tags-helper-functions.patch
arm64-kasan-export-mte-symbols-for-kasan-tests.patch
