![Andrey Ryabinin](/assets/img/avatar_default.png)
Update my email address. Signed-off-by: Andrey Ryabinin <ryabinin.a.a@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
538 lines
12 KiB
C
538 lines
12 KiB
C
/*
|
|
* This file contains shadow memory manipulation code.
|
|
*
|
|
* Copyright (c) 2014 Samsung Electronics Co., Ltd.
|
|
* Author: Andrey Ryabinin <ryabinin.a.a@gmail.com>
|
|
*
|
|
* Some of code borrowed from https://github.com/xairy/linux by
|
|
* Andrey Konovalov <adech.fo@gmail.com>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*
|
|
*/
|
|
|
|
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
|
|
#define DISABLE_BRANCH_PROFILING
|
|
|
|
#include <linux/export.h>
|
|
#include <linux/init.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/memblock.h>
|
|
#include <linux/memory.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/module.h>
|
|
#include <linux/printk.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/stacktrace.h>
|
|
#include <linux/string.h>
|
|
#include <linux/types.h>
|
|
#include <linux/vmalloc.h>
|
|
#include <linux/kasan.h>
|
|
|
|
#include "kasan.h"
|
|
#include "../slab.h"
|
|
|
|
/*
|
|
* Poisons the shadow memory for 'size' bytes starting from 'addr'.
|
|
* Memory addresses should be aligned to KASAN_SHADOW_SCALE_SIZE.
|
|
*/
|
|
static void kasan_poison_shadow(const void *address, size_t size, u8 value)
|
|
{
|
|
void *shadow_start, *shadow_end;
|
|
|
|
shadow_start = kasan_mem_to_shadow(address);
|
|
shadow_end = kasan_mem_to_shadow(address + size);
|
|
|
|
memset(shadow_start, value, shadow_end - shadow_start);
|
|
}
|
|
|
|
void kasan_unpoison_shadow(const void *address, size_t size)
|
|
{
|
|
kasan_poison_shadow(address, size, 0);
|
|
|
|
if (size & KASAN_SHADOW_MASK) {
|
|
u8 *shadow = (u8 *)kasan_mem_to_shadow(address + size);
|
|
*shadow = size & KASAN_SHADOW_MASK;
|
|
}
|
|
}
|
|
|
|
|
|
/*
|
|
* All functions below always inlined so compiler could
|
|
* perform better optimizations in each of __asan_loadX/__assn_storeX
|
|
* depending on memory access size X.
|
|
*/
|
|
|
|
static __always_inline bool memory_is_poisoned_1(unsigned long addr)
|
|
{
|
|
s8 shadow_value = *(s8 *)kasan_mem_to_shadow((void *)addr);
|
|
|
|
if (unlikely(shadow_value)) {
|
|
s8 last_accessible_byte = addr & KASAN_SHADOW_MASK;
|
|
return unlikely(last_accessible_byte >= shadow_value);
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
static __always_inline bool memory_is_poisoned_2(unsigned long addr)
|
|
{
|
|
u16 *shadow_addr = (u16 *)kasan_mem_to_shadow((void *)addr);
|
|
|
|
if (unlikely(*shadow_addr)) {
|
|
if (memory_is_poisoned_1(addr + 1))
|
|
return true;
|
|
|
|
if (likely(((addr + 1) & KASAN_SHADOW_MASK) != 0))
|
|
return false;
|
|
|
|
return unlikely(*(u8 *)shadow_addr);
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
static __always_inline bool memory_is_poisoned_4(unsigned long addr)
|
|
{
|
|
u16 *shadow_addr = (u16 *)kasan_mem_to_shadow((void *)addr);
|
|
|
|
if (unlikely(*shadow_addr)) {
|
|
if (memory_is_poisoned_1(addr + 3))
|
|
return true;
|
|
|
|
if (likely(((addr + 3) & KASAN_SHADOW_MASK) >= 3))
|
|
return false;
|
|
|
|
return unlikely(*(u8 *)shadow_addr);
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
static __always_inline bool memory_is_poisoned_8(unsigned long addr)
|
|
{
|
|
u16 *shadow_addr = (u16 *)kasan_mem_to_shadow((void *)addr);
|
|
|
|
if (unlikely(*shadow_addr)) {
|
|
if (memory_is_poisoned_1(addr + 7))
|
|
return true;
|
|
|
|
if (likely(((addr + 7) & KASAN_SHADOW_MASK) >= 7))
|
|
return false;
|
|
|
|
return unlikely(*(u8 *)shadow_addr);
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
static __always_inline bool memory_is_poisoned_16(unsigned long addr)
|
|
{
|
|
u32 *shadow_addr = (u32 *)kasan_mem_to_shadow((void *)addr);
|
|
|
|
if (unlikely(*shadow_addr)) {
|
|
u16 shadow_first_bytes = *(u16 *)shadow_addr;
|
|
s8 last_byte = (addr + 15) & KASAN_SHADOW_MASK;
|
|
|
|
if (unlikely(shadow_first_bytes))
|
|
return true;
|
|
|
|
if (likely(!last_byte))
|
|
return false;
|
|
|
|
return memory_is_poisoned_1(addr + 15);
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
static __always_inline unsigned long bytes_is_zero(const u8 *start,
|
|
size_t size)
|
|
{
|
|
while (size) {
|
|
if (unlikely(*start))
|
|
return (unsigned long)start;
|
|
start++;
|
|
size--;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static __always_inline unsigned long memory_is_zero(const void *start,
|
|
const void *end)
|
|
{
|
|
unsigned int words;
|
|
unsigned long ret;
|
|
unsigned int prefix = (unsigned long)start % 8;
|
|
|
|
if (end - start <= 16)
|
|
return bytes_is_zero(start, end - start);
|
|
|
|
if (prefix) {
|
|
prefix = 8 - prefix;
|
|
ret = bytes_is_zero(start, prefix);
|
|
if (unlikely(ret))
|
|
return ret;
|
|
start += prefix;
|
|
}
|
|
|
|
words = (end - start) / 8;
|
|
while (words) {
|
|
if (unlikely(*(u64 *)start))
|
|
return bytes_is_zero(start, 8);
|
|
start += 8;
|
|
words--;
|
|
}
|
|
|
|
return bytes_is_zero(start, (end - start) % 8);
|
|
}
|
|
|
|
static __always_inline bool memory_is_poisoned_n(unsigned long addr,
|
|
size_t size)
|
|
{
|
|
unsigned long ret;
|
|
|
|
ret = memory_is_zero(kasan_mem_to_shadow((void *)addr),
|
|
kasan_mem_to_shadow((void *)addr + size - 1) + 1);
|
|
|
|
if (unlikely(ret)) {
|
|
unsigned long last_byte = addr + size - 1;
|
|
s8 *last_shadow = (s8 *)kasan_mem_to_shadow((void *)last_byte);
|
|
|
|
if (unlikely(ret != (unsigned long)last_shadow ||
|
|
((last_byte & KASAN_SHADOW_MASK) >= *last_shadow)))
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
static __always_inline bool memory_is_poisoned(unsigned long addr, size_t size)
|
|
{
|
|
if (__builtin_constant_p(size)) {
|
|
switch (size) {
|
|
case 1:
|
|
return memory_is_poisoned_1(addr);
|
|
case 2:
|
|
return memory_is_poisoned_2(addr);
|
|
case 4:
|
|
return memory_is_poisoned_4(addr);
|
|
case 8:
|
|
return memory_is_poisoned_8(addr);
|
|
case 16:
|
|
return memory_is_poisoned_16(addr);
|
|
default:
|
|
BUILD_BUG();
|
|
}
|
|
}
|
|
|
|
return memory_is_poisoned_n(addr, size);
|
|
}
|
|
|
|
|
|
static __always_inline void check_memory_region(unsigned long addr,
|
|
size_t size, bool write)
|
|
{
|
|
struct kasan_access_info info;
|
|
|
|
if (unlikely(size == 0))
|
|
return;
|
|
|
|
if (unlikely((void *)addr <
|
|
kasan_shadow_to_mem((void *)KASAN_SHADOW_START))) {
|
|
info.access_addr = (void *)addr;
|
|
info.access_size = size;
|
|
info.is_write = write;
|
|
info.ip = _RET_IP_;
|
|
kasan_report_user_access(&info);
|
|
return;
|
|
}
|
|
|
|
if (likely(!memory_is_poisoned(addr, size)))
|
|
return;
|
|
|
|
kasan_report(addr, size, write, _RET_IP_);
|
|
}
|
|
|
|
void __asan_loadN(unsigned long addr, size_t size);
|
|
void __asan_storeN(unsigned long addr, size_t size);
|
|
|
|
#undef memset
|
|
void *memset(void *addr, int c, size_t len)
|
|
{
|
|
__asan_storeN((unsigned long)addr, len);
|
|
|
|
return __memset(addr, c, len);
|
|
}
|
|
|
|
#undef memmove
|
|
void *memmove(void *dest, const void *src, size_t len)
|
|
{
|
|
__asan_loadN((unsigned long)src, len);
|
|
__asan_storeN((unsigned long)dest, len);
|
|
|
|
return __memmove(dest, src, len);
|
|
}
|
|
|
|
#undef memcpy
|
|
void *memcpy(void *dest, const void *src, size_t len)
|
|
{
|
|
__asan_loadN((unsigned long)src, len);
|
|
__asan_storeN((unsigned long)dest, len);
|
|
|
|
return __memcpy(dest, src, len);
|
|
}
|
|
|
|
void kasan_alloc_pages(struct page *page, unsigned int order)
|
|
{
|
|
if (likely(!PageHighMem(page)))
|
|
kasan_unpoison_shadow(page_address(page), PAGE_SIZE << order);
|
|
}
|
|
|
|
void kasan_free_pages(struct page *page, unsigned int order)
|
|
{
|
|
if (likely(!PageHighMem(page)))
|
|
kasan_poison_shadow(page_address(page),
|
|
PAGE_SIZE << order,
|
|
KASAN_FREE_PAGE);
|
|
}
|
|
|
|
void kasan_poison_slab(struct page *page)
|
|
{
|
|
kasan_poison_shadow(page_address(page),
|
|
PAGE_SIZE << compound_order(page),
|
|
KASAN_KMALLOC_REDZONE);
|
|
}
|
|
|
|
void kasan_unpoison_object_data(struct kmem_cache *cache, void *object)
|
|
{
|
|
kasan_unpoison_shadow(object, cache->object_size);
|
|
}
|
|
|
|
void kasan_poison_object_data(struct kmem_cache *cache, void *object)
|
|
{
|
|
kasan_poison_shadow(object,
|
|
round_up(cache->object_size, KASAN_SHADOW_SCALE_SIZE),
|
|
KASAN_KMALLOC_REDZONE);
|
|
}
|
|
|
|
void kasan_slab_alloc(struct kmem_cache *cache, void *object)
|
|
{
|
|
kasan_kmalloc(cache, object, cache->object_size);
|
|
}
|
|
|
|
void kasan_slab_free(struct kmem_cache *cache, void *object)
|
|
{
|
|
unsigned long size = cache->object_size;
|
|
unsigned long rounded_up_size = round_up(size, KASAN_SHADOW_SCALE_SIZE);
|
|
|
|
/* RCU slabs could be legally used after free within the RCU period */
|
|
if (unlikely(cache->flags & SLAB_DESTROY_BY_RCU))
|
|
return;
|
|
|
|
kasan_poison_shadow(object, rounded_up_size, KASAN_KMALLOC_FREE);
|
|
}
|
|
|
|
void kasan_kmalloc(struct kmem_cache *cache, const void *object, size_t size)
|
|
{
|
|
unsigned long redzone_start;
|
|
unsigned long redzone_end;
|
|
|
|
if (unlikely(object == NULL))
|
|
return;
|
|
|
|
redzone_start = round_up((unsigned long)(object + size),
|
|
KASAN_SHADOW_SCALE_SIZE);
|
|
redzone_end = round_up((unsigned long)object + cache->object_size,
|
|
KASAN_SHADOW_SCALE_SIZE);
|
|
|
|
kasan_unpoison_shadow(object, size);
|
|
kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start,
|
|
KASAN_KMALLOC_REDZONE);
|
|
}
|
|
EXPORT_SYMBOL(kasan_kmalloc);
|
|
|
|
void kasan_kmalloc_large(const void *ptr, size_t size)
|
|
{
|
|
struct page *page;
|
|
unsigned long redzone_start;
|
|
unsigned long redzone_end;
|
|
|
|
if (unlikely(ptr == NULL))
|
|
return;
|
|
|
|
page = virt_to_page(ptr);
|
|
redzone_start = round_up((unsigned long)(ptr + size),
|
|
KASAN_SHADOW_SCALE_SIZE);
|
|
redzone_end = (unsigned long)ptr + (PAGE_SIZE << compound_order(page));
|
|
|
|
kasan_unpoison_shadow(ptr, size);
|
|
kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start,
|
|
KASAN_PAGE_REDZONE);
|
|
}
|
|
|
|
void kasan_krealloc(const void *object, size_t size)
|
|
{
|
|
struct page *page;
|
|
|
|
if (unlikely(object == ZERO_SIZE_PTR))
|
|
return;
|
|
|
|
page = virt_to_head_page(object);
|
|
|
|
if (unlikely(!PageSlab(page)))
|
|
kasan_kmalloc_large(object, size);
|
|
else
|
|
kasan_kmalloc(page->slab_cache, object, size);
|
|
}
|
|
|
|
void kasan_kfree(void *ptr)
|
|
{
|
|
struct page *page;
|
|
|
|
page = virt_to_head_page(ptr);
|
|
|
|
if (unlikely(!PageSlab(page)))
|
|
kasan_poison_shadow(ptr, PAGE_SIZE << compound_order(page),
|
|
KASAN_FREE_PAGE);
|
|
else
|
|
kasan_slab_free(page->slab_cache, ptr);
|
|
}
|
|
|
|
void kasan_kfree_large(const void *ptr)
|
|
{
|
|
struct page *page = virt_to_page(ptr);
|
|
|
|
kasan_poison_shadow(ptr, PAGE_SIZE << compound_order(page),
|
|
KASAN_FREE_PAGE);
|
|
}
|
|
|
|
int kasan_module_alloc(void *addr, size_t size)
|
|
{
|
|
void *ret;
|
|
size_t shadow_size;
|
|
unsigned long shadow_start;
|
|
|
|
shadow_start = (unsigned long)kasan_mem_to_shadow(addr);
|
|
shadow_size = round_up(size >> KASAN_SHADOW_SCALE_SHIFT,
|
|
PAGE_SIZE);
|
|
|
|
if (WARN_ON(!PAGE_ALIGNED(shadow_start)))
|
|
return -EINVAL;
|
|
|
|
ret = __vmalloc_node_range(shadow_size, 1, shadow_start,
|
|
shadow_start + shadow_size,
|
|
GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
|
|
PAGE_KERNEL, VM_NO_GUARD, NUMA_NO_NODE,
|
|
__builtin_return_address(0));
|
|
|
|
if (ret) {
|
|
find_vm_area(addr)->flags |= VM_KASAN;
|
|
return 0;
|
|
}
|
|
|
|
return -ENOMEM;
|
|
}
|
|
|
|
void kasan_free_shadow(const struct vm_struct *vm)
|
|
{
|
|
if (vm->flags & VM_KASAN)
|
|
vfree(kasan_mem_to_shadow(vm->addr));
|
|
}
|
|
|
|
static void register_global(struct kasan_global *global)
|
|
{
|
|
size_t aligned_size = round_up(global->size, KASAN_SHADOW_SCALE_SIZE);
|
|
|
|
kasan_unpoison_shadow(global->beg, global->size);
|
|
|
|
kasan_poison_shadow(global->beg + aligned_size,
|
|
global->size_with_redzone - aligned_size,
|
|
KASAN_GLOBAL_REDZONE);
|
|
}
|
|
|
|
void __asan_register_globals(struct kasan_global *globals, size_t size)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < size; i++)
|
|
register_global(&globals[i]);
|
|
}
|
|
EXPORT_SYMBOL(__asan_register_globals);
|
|
|
|
void __asan_unregister_globals(struct kasan_global *globals, size_t size)
|
|
{
|
|
}
|
|
EXPORT_SYMBOL(__asan_unregister_globals);
|
|
|
|
#define DEFINE_ASAN_LOAD_STORE(size) \
|
|
void __asan_load##size(unsigned long addr) \
|
|
{ \
|
|
check_memory_region(addr, size, false); \
|
|
} \
|
|
EXPORT_SYMBOL(__asan_load##size); \
|
|
__alias(__asan_load##size) \
|
|
void __asan_load##size##_noabort(unsigned long); \
|
|
EXPORT_SYMBOL(__asan_load##size##_noabort); \
|
|
void __asan_store##size(unsigned long addr) \
|
|
{ \
|
|
check_memory_region(addr, size, true); \
|
|
} \
|
|
EXPORT_SYMBOL(__asan_store##size); \
|
|
__alias(__asan_store##size) \
|
|
void __asan_store##size##_noabort(unsigned long); \
|
|
EXPORT_SYMBOL(__asan_store##size##_noabort)
|
|
|
|
DEFINE_ASAN_LOAD_STORE(1);
|
|
DEFINE_ASAN_LOAD_STORE(2);
|
|
DEFINE_ASAN_LOAD_STORE(4);
|
|
DEFINE_ASAN_LOAD_STORE(8);
|
|
DEFINE_ASAN_LOAD_STORE(16);
|
|
|
|
void __asan_loadN(unsigned long addr, size_t size)
|
|
{
|
|
check_memory_region(addr, size, false);
|
|
}
|
|
EXPORT_SYMBOL(__asan_loadN);
|
|
|
|
__alias(__asan_loadN)
|
|
void __asan_loadN_noabort(unsigned long, size_t);
|
|
EXPORT_SYMBOL(__asan_loadN_noabort);
|
|
|
|
void __asan_storeN(unsigned long addr, size_t size)
|
|
{
|
|
check_memory_region(addr, size, true);
|
|
}
|
|
EXPORT_SYMBOL(__asan_storeN);
|
|
|
|
__alias(__asan_storeN)
|
|
void __asan_storeN_noabort(unsigned long, size_t);
|
|
EXPORT_SYMBOL(__asan_storeN_noabort);
|
|
|
|
/* to shut up compiler complaints */
|
|
void __asan_handle_no_return(void) {}
|
|
EXPORT_SYMBOL(__asan_handle_no_return);
|
|
|
|
#ifdef CONFIG_MEMORY_HOTPLUG
|
|
static int kasan_mem_notifier(struct notifier_block *nb,
|
|
unsigned long action, void *data)
|
|
{
|
|
return (action == MEM_GOING_ONLINE) ? NOTIFY_BAD : NOTIFY_OK;
|
|
}
|
|
|
|
static int __init kasan_memhotplug_init(void)
|
|
{
|
|
pr_err("WARNING: KASan doesn't support memory hot-add\n");
|
|
pr_err("Memory hot-add will be disabled\n");
|
|
|
|
hotplug_memory_notifier(kasan_mem_notifier, 0);
|
|
|
|
return 0;
|
|
}
|
|
|
|
module_init(kasan_memhotplug_init);
|
|
#endif
|