[linux.git] / mm / kasan / kasan.c

/*
 * This file contains shadow memory manipulation code.
 *
 * Copyright (c) 2014 Samsung Electronics Co., Ltd.
 * Author: Andrey Ryabinin <[email protected]>
 *
 * Some code borrowed from https://github.com/xairy/kasan-prototype by
 *        Andrey Konovalov <[email protected]>
 *
 * 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 single shadow byte covers 2-byte access, we don't
		 * need to do anything more. Otherwise, test the first
		 * shadow byte.
		 */
		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 single shadow byte covers 4-byte access, we don't
		 * need to do anything more. Otherwise, test the first
		 * shadow byte.
		 */
		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 single shadow byte covers 8-byte access, we don't
		 * need to do anything more. Otherwise, test the first
		 * shadow byte.
		 */
		if (likely(IS_ALIGNED(addr, KASAN_SHADOW_SCALE_SIZE)))
			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;

		if (unlikely(shadow_first_bytes))
			return true;

		/*
		 * If two shadow bytes covers 16-byte access, we don't
		 * need to do anything more. Otherwise, test the last
		 * shadow byte.
		 */
		if (likely(IS_ALIGNED(addr, KASAN_SHADOW_SCALE_SIZE)))
			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 ||
			((long)(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)
{
	if (unlikely(size == 0))
		return;

	if (unlikely((void *)addr <
		kasan_shadow_to_mem((void *)KASAN_SHADOW_START))) {
		kasan_report(addr, size, write, _RET_IP_);
		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
Commit	Line	Data
0b24becc AR	1	/*
	2	* This file contains shadow memory manipulation code.
	3	*
	4	* Copyright (c) 2014 Samsung Electronics Co., Ltd.
2baf9e89	5	* Author: Andrey Ryabinin <[email protected]>
0b24becc	6	*
5d0926ef	7	* Some code borrowed from https://github.com/xairy/kasan-prototype by
0b24becc AR	8	* Andrey Konovalov <[email protected]>
	9	*
	10	* This program is free software; you can redistribute it and/or modify
	11	* it under the terms of the GNU General Public License version 2 as
	12	* published by the Free Software Foundation.
	13	*
	14	*/
	15
	16	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	17	#define DISABLE_BRANCH_PROFILING
	18
	19	#include <linux/export.h>
	20	#include <linux/init.h>
	21	#include <linux/kernel.h>
	22	#include <linux/memblock.h>
786a8959	23	#include <linux/memory.h>
0b24becc	24	#include <linux/mm.h>
bebf56a1	25	#include <linux/module.h>
0b24becc AR	26	#include <linux/printk.h>
	27	#include <linux/sched.h>
	28	#include <linux/slab.h>
	29	#include <linux/stacktrace.h>
	30	#include <linux/string.h>
	31	#include <linux/types.h>
a5af5aa8	32	#include <linux/vmalloc.h>
0b24becc AR	33	#include <linux/kasan.h>
	34
	35	#include "kasan.h"
0316bec2	36	#include "../slab.h"
0b24becc AR	37
	38	/*
	39	* Poisons the shadow memory for 'size' bytes starting from 'addr'.
	40	* Memory addresses should be aligned to KASAN_SHADOW_SCALE_SIZE.
	41	*/
	42	static void kasan_poison_shadow(const void *address, size_t size, u8 value)
	43	{
	44	void shadow_start, shadow_end;
	45
	46	shadow_start = kasan_mem_to_shadow(address);
	47	shadow_end = kasan_mem_to_shadow(address + size);
	48
	49	memset(shadow_start, value, shadow_end - shadow_start);
	50	}
	51
	52	void kasan_unpoison_shadow(const void *address, size_t size)
	53	{
	54	kasan_poison_shadow(address, size, 0);
	55
	56	if (size & KASAN_SHADOW_MASK) {
	57	u8 shadow = (u8 )kasan_mem_to_shadow(address + size);
	58	*shadow = size & KASAN_SHADOW_MASK;
	59	}
	60	}
	61
	62
	63	/*
	64	* All functions below always inlined so compiler could
	65	* perform better optimizations in each of __asan_loadX/__assn_storeX
	66	* depending on memory access size X.
	67	*/
	68
	69	static __always_inline bool memory_is_poisoned_1(unsigned long addr)
	70	{
	71	s8 shadow_value = (s8 )kasan_mem_to_shadow((void *)addr);
	72
	73	if (unlikely(shadow_value)) {
	74	s8 last_accessible_byte = addr & KASAN_SHADOW_MASK;
	75	return unlikely(last_accessible_byte >= shadow_value);
	76	}
	77
	78	return false;
	79	}
	80
	81	static __always_inline bool memory_is_poisoned_2(unsigned long addr)
	82	{
	83	u16 shadow_addr = (u16 )kasan_mem_to_shadow((void *)addr);
	84
	85	if (unlikely(*shadow_addr)) {
	86	if (memory_is_poisoned_1(addr + 1))
	87	return true;
	88
10f70262 XQ	89	/*
	90	* If single shadow byte covers 2-byte access, we don't
	91	* need to do anything more. Otherwise, test the first
	92	* shadow byte.
	93	*/
0b24becc AR	94	if (likely(((addr + 1) & KASAN_SHADOW_MASK) != 0))
	95	return false;
	96
	97	return unlikely((u8 )shadow_addr);
	98	}
	99
	100	return false;
	101	}
	102
	103	static __always_inline bool memory_is_poisoned_4(unsigned long addr)
	104	{
	105	u16 shadow_addr = (u16 )kasan_mem_to_shadow((void *)addr);
	106
	107	if (unlikely(*shadow_addr)) {
	108	if (memory_is_poisoned_1(addr + 3))
	109	return true;
	110
10f70262 XQ	111	/*
	112	* If single shadow byte covers 4-byte access, we don't
	113	* need to do anything more. Otherwise, test the first
	114	* shadow byte.
	115	*/
0b24becc AR	116	if (likely(((addr + 3) & KASAN_SHADOW_MASK) >= 3))
	117	return false;
	118
	119	return unlikely((u8 )shadow_addr);
	120	}
	121
	122	return false;
	123	}
	124
	125	static __always_inline bool memory_is_poisoned_8(unsigned long addr)
	126	{
	127	u16 shadow_addr = (u16 )kasan_mem_to_shadow((void *)addr);
	128
	129	if (unlikely(*shadow_addr)) {
	130	if (memory_is_poisoned_1(addr + 7))
	131	return true;
	132
10f70262 XQ	133	/*
	134	* If single shadow byte covers 8-byte access, we don't
	135	* need to do anything more. Otherwise, test the first
	136	* shadow byte.
	137	*/
	138	if (likely(IS_ALIGNED(addr, KASAN_SHADOW_SCALE_SIZE)))
0b24becc AR	139	return false;
	140
	141	return unlikely((u8 )shadow_addr);
	142	}
	143
	144	return false;
	145	}
	146
	147	static __always_inline bool memory_is_poisoned_16(unsigned long addr)
	148	{
	149	u32 shadow_addr = (u32 )kasan_mem_to_shadow((void *)addr);
	150
	151	if (unlikely(*shadow_addr)) {
	152	u16 shadow_first_bytes = (u16 )shadow_addr;
0b24becc AR	153
	154	if (unlikely(shadow_first_bytes))
	155	return true;
	156
10f70262 XQ	157	/*
	158	* If two shadow bytes covers 16-byte access, we don't
	159	* need to do anything more. Otherwise, test the last
	160	* shadow byte.
	161	*/
	162	if (likely(IS_ALIGNED(addr, KASAN_SHADOW_SCALE_SIZE)))
0b24becc AR	163	return false;
	164
	165	return memory_is_poisoned_1(addr + 15);
	166	}
	167
	168	return false;
	169	}
	170
	171	static __always_inline unsigned long bytes_is_zero(const u8 *start,
	172	size_t size)
	173	{
	174	while (size) {
	175	if (unlikely(*start))
	176	return (unsigned long)start;
	177	start++;
	178	size--;
	179	}
	180
	181	return 0;
	182	}
	183
	184	static __always_inline unsigned long memory_is_zero(const void *start,
	185	const void *end)
	186	{
	187	unsigned int words;
	188	unsigned long ret;
	189	unsigned int prefix = (unsigned long)start % 8;
	190
	191	if (end - start <= 16)
	192	return bytes_is_zero(start, end - start);
	193
	194	if (prefix) {
	195	prefix = 8 - prefix;
	196	ret = bytes_is_zero(start, prefix);
	197	if (unlikely(ret))
	198	return ret;
	199	start += prefix;
	200	}
	201
	202	words = (end - start) / 8;
	203	while (words) {
	204	if (unlikely((u64 )start))
	205	return bytes_is_zero(start, 8);
	206	start += 8;
	207	words--;
	208	}
	209
	210	return bytes_is_zero(start, (end - start) % 8);
	211	}
	212
	213	static __always_inline bool memory_is_poisoned_n(unsigned long addr,
	214	size_t size)
	215	{
	216	unsigned long ret;
	217
	218	ret = memory_is_zero(kasan_mem_to_shadow((void *)addr),
	219	kasan_mem_to_shadow((void *)addr + size - 1) + 1);
	220
	221	if (unlikely(ret)) {
	222	unsigned long last_byte = addr + size - 1;
	223	s8 last_shadow = (s8 )kasan_mem_to_shadow((void *)last_byte);
	224
	225	if (unlikely(ret != (unsigned long)last_shadow \|\|
e0d57714	226	((long)(last_byte & KASAN_SHADOW_MASK) >= *last_shadow)))
0b24becc AR	227	return true;
	228	}
	229	return false;
	230	}
	231
	232	static __always_inline bool memory_is_poisoned(unsigned long addr, size_t size)
	233	{
	234	if (__builtin_constant_p(size)) {
	235	switch (size) {
	236	case 1:
	237	return memory_is_poisoned_1(addr);
	238	case 2:
	239	return memory_is_poisoned_2(addr);
	240	case 4:
	241	return memory_is_poisoned_4(addr);
	242	case 8:
	243	return memory_is_poisoned_8(addr);
	244	case 16:
	245	return memory_is_poisoned_16(addr);
	246	default:
	247	BUILD_BUG();
	248	}
	249	}
	250
	251	return memory_is_poisoned_n(addr, size);
	252	}
	253
	254
	255	static __always_inline void check_memory_region(unsigned long addr,
	256	size_t size, bool write)
	257	{
0b24becc AR	258	if (unlikely(size == 0))
	259	return;
	260
	261	if (unlikely((void *)addr <
	262	kasan_shadow_to_mem((void *)KASAN_SHADOW_START))) {
e9121076	263	kasan_report(addr, size, write, _RET_IP_);
0b24becc AR	264	return;
	265	}
	266
	267	if (likely(!memory_is_poisoned(addr, size)))
	268	return;
	269
	270	kasan_report(addr, size, write, _RET_IP_);
	271	}
	272
393f203f AR	273	void __asan_loadN(unsigned long addr, size_t size);
	274	void __asan_storeN(unsigned long addr, size_t size);
	275
	276	#undef memset
	277	void memset(void addr, int c, size_t len)
	278	{
	279	__asan_storeN((unsigned long)addr, len);
	280
	281	return __memset(addr, c, len);
	282	}
	283
	284	#undef memmove
	285	void memmove(void dest, const void *src, size_t len)
	286	{
	287	__asan_loadN((unsigned long)src, len);
	288	__asan_storeN((unsigned long)dest, len);
	289
	290	return __memmove(dest, src, len);
	291	}
	292
	293	#undef memcpy
	294	void memcpy(void dest, const void *src, size_t len)
	295	{
	296	__asan_loadN((unsigned long)src, len);
	297	__asan_storeN((unsigned long)dest, len);
	298
	299	return __memcpy(dest, src, len);
	300	}
	301
b8c73fc2 AR	302	void kasan_alloc_pages(struct page *page, unsigned int order)
	303	{
	304	if (likely(!PageHighMem(page)))
	305	kasan_unpoison_shadow(page_address(page), PAGE_SIZE << order);
	306	}
	307
	308	void kasan_free_pages(struct page *page, unsigned int order)
	309	{
	310	if (likely(!PageHighMem(page)))
	311	kasan_poison_shadow(page_address(page),
	312	PAGE_SIZE << order,
	313	KASAN_FREE_PAGE);
	314	}
	315
0316bec2 AR	316	void kasan_poison_slab(struct page *page)
	317	{
	318	kasan_poison_shadow(page_address(page),
	319	PAGE_SIZE << compound_order(page),
	320	KASAN_KMALLOC_REDZONE);
	321	}
	322
	323	void kasan_unpoison_object_data(struct kmem_cache cache, void object)
	324	{
	325	kasan_unpoison_shadow(object, cache->object_size);
	326	}
	327
	328	void kasan_poison_object_data(struct kmem_cache cache, void object)
	329	{
	330	kasan_poison_shadow(object,
	331	round_up(cache->object_size, KASAN_SHADOW_SCALE_SIZE),
	332	KASAN_KMALLOC_REDZONE);
	333	}
	334
	335	void kasan_slab_alloc(struct kmem_cache cache, void object)
	336	{
	337	kasan_kmalloc(cache, object, cache->object_size);
	338	}
	339
	340	void kasan_slab_free(struct kmem_cache cache, void object)
	341	{
	342	unsigned long size = cache->object_size;
	343	unsigned long rounded_up_size = round_up(size, KASAN_SHADOW_SCALE_SIZE);
	344
	345	/* RCU slabs could be legally used after free within the RCU period */
	346	if (unlikely(cache->flags & SLAB_DESTROY_BY_RCU))
	347	return;
	348
	349	kasan_poison_shadow(object, rounded_up_size, KASAN_KMALLOC_FREE);
	350	}
	351
	352	void kasan_kmalloc(struct kmem_cache cache, const void object, size_t size)
	353	{
	354	unsigned long redzone_start;
	355	unsigned long redzone_end;
	356
	357	if (unlikely(object == NULL))
	358	return;
	359
	360	redzone_start = round_up((unsigned long)(object + size),
	361	KASAN_SHADOW_SCALE_SIZE);
	362	redzone_end = round_up((unsigned long)object + cache->object_size,
	363	KASAN_SHADOW_SCALE_SIZE);
	364
	365	kasan_unpoison_shadow(object, size);
	366	kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start,
	367	KASAN_KMALLOC_REDZONE);
	368	}
	369	EXPORT_SYMBOL(kasan_kmalloc);
	370
	371	void kasan_kmalloc_large(const void *ptr, size_t size)
	372	{
	373	struct page *page;
	374	unsigned long redzone_start;
	375	unsigned long redzone_end;
	376
	377	if (unlikely(ptr == NULL))
	378	return;
	379
380	page = virt_to_page(ptr);
381	redzone_start = round_up((unsigned long)(ptr + size),
382	KASAN_SHADOW_SCALE_SIZE);
383	redzone_end = (unsigned long)ptr + (PAGE_SIZE << compound_order(page));
384
385	kasan_unpoison_shadow(ptr, size);
386	kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start,
387	KASAN_PAGE_REDZONE);
388	}
389
390	void kasan_krealloc(const void *object, size_t size)
391	{
392	struct page *page;
393
394	if (unlikely(object == ZERO_SIZE_PTR))
395	return;
396
397	page = virt_to_head_page(object);
398
399	if (unlikely(!PageSlab(page)))
400	kasan_kmalloc_large(object, size);
401	else
402	kasan_kmalloc(page->slab_cache, object, size);
403	}
404
92393615 AR	405	void kasan_kfree(void *ptr)
	406	{
	407	struct page *page;
	408
	409	page = virt_to_head_page(ptr);
	410
	411	if (unlikely(!PageSlab(page)))
	412	kasan_poison_shadow(ptr, PAGE_SIZE << compound_order(page),
	413	KASAN_FREE_PAGE);
	414	else
	415	kasan_slab_free(page->slab_cache, ptr);
	416	}
	417
0316bec2 AR	418	void kasan_kfree_large(const void *ptr)
	419	{
	420	struct page *page = virt_to_page(ptr);
	421
	422	kasan_poison_shadow(ptr, PAGE_SIZE << compound_order(page),
	423	KASAN_FREE_PAGE);
	424	}
	425
bebf56a1 AR	426	int kasan_module_alloc(void *addr, size_t size)
	427	{
	428	void *ret;
	429	size_t shadow_size;
	430	unsigned long shadow_start;
	431
	432	shadow_start = (unsigned long)kasan_mem_to_shadow(addr);
	433	shadow_size = round_up(size >> KASAN_SHADOW_SCALE_SHIFT,
	434	PAGE_SIZE);
	435
	436	if (WARN_ON(!PAGE_ALIGNED(shadow_start)))
	437	return -EINVAL;
	438
	439	ret = __vmalloc_node_range(shadow_size, 1, shadow_start,
	440	shadow_start + shadow_size,
	441	GFP_KERNEL \| __GFP_HIGHMEM \| __GFP_ZERO,
	442	PAGE_KERNEL, VM_NO_GUARD, NUMA_NO_NODE,
	443	__builtin_return_address(0));
a5af5aa8 AR	444
	445	if (ret) {
	446	find_vm_area(addr)->flags \|= VM_KASAN;
	447	return 0;
	448	}
	449
	450	return -ENOMEM;
bebf56a1 AR	451	}
bebf56a1 AR	452
a5af5aa8	453	void kasan_free_shadow(const struct vm_struct *vm)
bebf56a1	454	{
a5af5aa8 AR	455	if (vm->flags & VM_KASAN)
a5af5aa8 AR	456	vfree(kasan_mem_to_shadow(vm->addr));
bebf56a1 AR	457	}
	458
	459	static void register_global(struct kasan_global *global)
	460	{
	461	size_t aligned_size = round_up(global->size, KASAN_SHADOW_SCALE_SIZE);
	462
	463	kasan_unpoison_shadow(global->beg, global->size);
	464
	465	kasan_poison_shadow(global->beg + aligned_size,
	466	global->size_with_redzone - aligned_size,
	467	KASAN_GLOBAL_REDZONE);
	468	}
	469
	470	void __asan_register_globals(struct kasan_global *globals, size_t size)
	471	{
	472	int i;
	473
	474	for (i = 0; i < size; i++)
	475	register_global(&globals[i]);
	476	}
	477	EXPORT_SYMBOL(__asan_register_globals);
	478
	479	void __asan_unregister_globals(struct kasan_global *globals, size_t size)
	480	{
	481	}
	482	EXPORT_SYMBOL(__asan_unregister_globals);
	483
0b24becc AR	484	#define DEFINE_ASAN_LOAD_STORE(size) \
	485	void __asan_load##size(unsigned long addr) \
	486	{ \
	487	check_memory_region(addr, size, false); \
	488	} \
	489	EXPORT_SYMBOL(__asan_load##size); \
	490	__alias(__asan_load##size) \
	491	void __asan_load##size##_noabort(unsigned long); \
	492	EXPORT_SYMBOL(__asan_load##size##_noabort); \
	493	void __asan_store##size(unsigned long addr) \
	494	{ \
	495	check_memory_region(addr, size, true); \
	496	} \
	497	EXPORT_SYMBOL(__asan_store##size); \
	498	__alias(__asan_store##size) \
	499	void __asan_store##size##_noabort(unsigned long); \
	500	EXPORT_SYMBOL(__asan_store##size##_noabort)
	501
	502	DEFINE_ASAN_LOAD_STORE(1);
	503	DEFINE_ASAN_LOAD_STORE(2);
	504	DEFINE_ASAN_LOAD_STORE(4);
	505	DEFINE_ASAN_LOAD_STORE(8);
	506	DEFINE_ASAN_LOAD_STORE(16);
	507
	508	void __asan_loadN(unsigned long addr, size_t size)
	509	{
	510	check_memory_region(addr, size, false);
	511	}
	512	EXPORT_SYMBOL(__asan_loadN);
	513
	514	__alias(__asan_loadN)
	515	void __asan_loadN_noabort(unsigned long, size_t);
	516	EXPORT_SYMBOL(__asan_loadN_noabort);
	517
	518	void __asan_storeN(unsigned long addr, size_t size)
	519	{
	520	check_memory_region(addr, size, true);
	521	}
	522	EXPORT_SYMBOL(__asan_storeN);
	523
	524	__alias(__asan_storeN)
	525	void __asan_storeN_noabort(unsigned long, size_t);
	526	EXPORT_SYMBOL(__asan_storeN_noabort);
	527
	528	/* to shut up compiler complaints */
	529	void __asan_handle_no_return(void) {}
	530	EXPORT_SYMBOL(__asan_handle_no_return);
786a8959 AR	531
	532	#ifdef CONFIG_MEMORY_HOTPLUG
	533	static int kasan_mem_notifier(struct notifier_block *nb,
	534	unsigned long action, void *data)
	535	{
	536	return (action == MEM_GOING_ONLINE) ? NOTIFY_BAD : NOTIFY_OK;
	537	}
	538
	539	static int __init kasan_memhotplug_init(void)
	540	{
25add7ec	541	pr_err("WARNING: KASAN doesn't support memory hot-add\n");
786a8959 AR	542	pr_err("Memory hot-add will be disabled\n");
	543
	544	hotplug_memory_notifier(kasan_mem_notifier, 0);
	545
	546	return 0;
	547	}
	548
	549	module_init(kasan_memhotplug_init);
	550	#endif