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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/14ffc4cd867e0b1ed58f7527e3b748a1b4ad08aa.1612546384.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Andrey Konovalov 2021-02-25 17:20:11 -08:00 committed by Linus Torvalds
parent df54b38312
commit 200072ce33
2 changed files with 34 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
include/linux/kasan.h
View File

@ -200,6 +200,13 @@ static __always_inline bool kasan_slab_free(struct kmem_cache *s, void *object)
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_check kasan_krealloc(const void *object,
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(struct kmem_cache *s, void *object)
{
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 void *object, size_t new_size,
{
return (void *)object;
}
static inline void kasan_kfree_large(void *ptr) {}
static inline bool kasan_check_byte(const void *address)
{
return true;

36
mm/kasan/common.c
View File

@ -364,6 +364,31 @@ bool __kasan_slab_free(struct kmem_cache *cache, void *object, unsigned long ip)
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, unsigned long ip)
* 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(const void *object, size_t size, gfp_t flag
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)) {