[mirror_ubuntu-zesty-kernel.git] / mm / kasan / kasan.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
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 <ryabinin.a.a@gmail.com>
0b24becc AR	6	*
	7	* Some of code borrowed from https://github.com/xairy/linux by
	8	* Andrey Konovalov <adech.fo@gmail.com>
	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
	89	if (likely(((addr + 1) & KASAN_SHADOW_MASK) != 0))
	90	return false;
	91
	92	return unlikely((u8 )shadow_addr);
	93	}
	94
	95	return false;
	96	}
	97
	98	static __always_inline bool memory_is_poisoned_4(unsigned long addr)
	99	{
	100	u16 shadow_addr = (u16 )kasan_mem_to_shadow((void *)addr);
101
102	if (unlikely(*shadow_addr)) {
103	if (memory_is_poisoned_1(addr + 3))
104	return true;
105
106	if (likely(((addr + 3) & KASAN_SHADOW_MASK) >= 3))
107	return false;
108
109	return unlikely((u8 )shadow_addr);
110	}
111
112	return false;
113	}
114
115	static __always_inline bool memory_is_poisoned_8(unsigned long addr)
116	{
117	u16 shadow_addr = (u16 )kasan_mem_to_shadow((void *)addr);
118
119	if (unlikely(*shadow_addr)) {
120	if (memory_is_poisoned_1(addr + 7))
121	return true;
122
123	if (likely(((addr + 7) & KASAN_SHADOW_MASK) >= 7))
124	return false;
125
126	return unlikely((u8 )shadow_addr);
127	}
128
129	return false;
130	}
131
132	static __always_inline bool memory_is_poisoned_16(unsigned long addr)
133	{
134	u32 shadow_addr = (u32 )kasan_mem_to_shadow((void *)addr);
135
136	if (unlikely(*shadow_addr)) {
137	u16 shadow_first_bytes = (u16 )shadow_addr;
138	s8 last_byte = (addr + 15) & KASAN_SHADOW_MASK;
139
140	if (unlikely(shadow_first_bytes))
141	return true;
142
143	if (likely(!last_byte))
144	return false;
145
146	return memory_is_poisoned_1(addr + 15);
147	}
148
149	return false;
150	}
151
152	static __always_inline unsigned long bytes_is_zero(const u8 *start,
153	size_t size)
154	{
155	while (size) {
156	if (unlikely(*start))
157	return (unsigned long)start;
158	start++;
159	size--;
160	}
161
162	return 0;
163	}
164
165	static __always_inline unsigned long memory_is_zero(const void *start,
166	const void *end)
167	{
168	unsigned int words;
169	unsigned long ret;
170	unsigned int prefix = (unsigned long)start % 8;
171
172	if (end - start <= 16)
173	return bytes_is_zero(start, end - start);
174
175	if (prefix) {
176	prefix = 8 - prefix;
177	ret = bytes_is_zero(start, prefix);
178	if (unlikely(ret))
179	return ret;
180	start += prefix;
181	}
182
183	words = (end - start) / 8;
184	while (words) {
185	if (unlikely((u64 )start))
186	return bytes_is_zero(start, 8);
187	start += 8;
188	words--;
189	}
190
191	return bytes_is_zero(start, (end - start) % 8);
192	}
193
194	static __always_inline bool memory_is_poisoned_n(unsigned long addr,
195	size_t size)
196	{
197	unsigned long ret;
198
199	ret = memory_is_zero(kasan_mem_to_shadow((void *)addr),
200	kasan_mem_to_shadow((void *)addr + size - 1) + 1);
201
202	if (unlikely(ret)) {
203	unsigned long last_byte = addr + size - 1;
204	s8 last_shadow = (s8 )kasan_mem_to_shadow((void *)last_byte);
205
206	if (unlikely(ret != (unsigned long)last_shadow \|\|
207	((last_byte & KASAN_SHADOW_MASK) >= *last_shadow)))
208	return true;
209	}
210	return false;
211	}
212
213	static __always_inline bool memory_is_poisoned(unsigned long addr, size_t size)
214	{
215	if (__builtin_constant_p(size)) {
216	switch (size) {
217	case 1:
218	return memory_is_poisoned_1(addr);
219	case 2:
220	return memory_is_poisoned_2(addr);
221	case 4:
222	return memory_is_poisoned_4(addr);
223	case 8:
224	return memory_is_poisoned_8(addr);
225	case 16:
226	return memory_is_poisoned_16(addr);
227	default:
228	BUILD_BUG();
229	}
230	}
231
232	return memory_is_poisoned_n(addr, size);
233	}
234
235
236	static __always_inline void check_memory_region(unsigned long addr,
237	size_t size, bool write)
238	{
239	struct kasan_access_info info;
240
241	if (unlikely(size == 0))
242	return;
243
244	if (unlikely((void *)addr <
245	kasan_shadow_to_mem((void *)KASAN_SHADOW_START))) {
246	info.access_addr = (void *)addr;
247	info.access_size = size;
248	info.is_write = write;
249	info.ip = _RET_IP_;
250	kasan_report_user_access(&info);
251	return;
252	}
253
254	if (likely(!memory_is_poisoned(addr, size)))
255	return;
256
257	kasan_report(addr, size, write, _RET_IP_);
258	}
259
393f203f AR	260	void __asan_loadN(unsigned long addr, size_t size);
	261	void __asan_storeN(unsigned long addr, size_t size);
	262
	263	#undef memset
	264	void memset(void addr, int c, size_t len)
	265	{
	266	__asan_storeN((unsigned long)addr, len);
	267
	268	return __memset(addr, c, len);
	269	}
	270
	271	#undef memmove
	272	void memmove(void dest, const void *src, size_t len)
	273	{
	274	__asan_loadN((unsigned long)src, len);
	275	__asan_storeN((unsigned long)dest, len);
	276
	277	return __memmove(dest, src, len);
	278	}
	279
	280	#undef memcpy
	281	void memcpy(void dest, const void *src, size_t len)
	282	{
	283	__asan_loadN((unsigned long)src, len);
	284	__asan_storeN((unsigned long)dest, len);
	285
	286	return __memcpy(dest, src, len);
	287	}
	288
b8c73fc2 AR	289	void kasan_alloc_pages(struct page *page, unsigned int order)
	290	{
	291	if (likely(!PageHighMem(page)))
	292	kasan_unpoison_shadow(page_address(page), PAGE_SIZE << order);
	293	}
	294
	295	void kasan_free_pages(struct page *page, unsigned int order)
	296	{
	297	if (likely(!PageHighMem(page)))
	298	kasan_poison_shadow(page_address(page),
	299	PAGE_SIZE << order,
	300	KASAN_FREE_PAGE);
	301	}
	302
0316bec2 AR	303	void kasan_poison_slab(struct page *page)
	304	{
	305	kasan_poison_shadow(page_address(page),
	306	PAGE_SIZE << compound_order(page),
	307	KASAN_KMALLOC_REDZONE);
	308	}
	309
	310	void kasan_unpoison_object_data(struct kmem_cache cache, void object)
	311	{
	312	kasan_unpoison_shadow(object, cache->object_size);
	313	}
	314
	315	void kasan_poison_object_data(struct kmem_cache cache, void object)
	316	{
	317	kasan_poison_shadow(object,
	318	round_up(cache->object_size, KASAN_SHADOW_SCALE_SIZE),
	319	KASAN_KMALLOC_REDZONE);
	320	}
	321
	322	void kasan_slab_alloc(struct kmem_cache cache, void object)
	323	{
	324	kasan_kmalloc(cache, object, cache->object_size);
	325	}
	326
	327	void kasan_slab_free(struct kmem_cache cache, void object)
	328	{
	329	unsigned long size = cache->object_size;
	330	unsigned long rounded_up_size = round_up(size, KASAN_SHADOW_SCALE_SIZE);
	331
	332	/* RCU slabs could be legally used after free within the RCU period */
	333	if (unlikely(cache->flags & SLAB_DESTROY_BY_RCU))
	334	return;
	335
	336	kasan_poison_shadow(object, rounded_up_size, KASAN_KMALLOC_FREE);
	337	}
	338
	339	void kasan_kmalloc(struct kmem_cache cache, const void object, size_t size)
	340	{
	341	unsigned long redzone_start;
	342	unsigned long redzone_end;
	343
	344	if (unlikely(object == NULL))
	345	return;
	346
	347	redzone_start = round_up((unsigned long)(object + size),
	348	KASAN_SHADOW_SCALE_SIZE);
	349	redzone_end = round_up((unsigned long)object + cache->object_size,
	350	KASAN_SHADOW_SCALE_SIZE);
	351
	352	kasan_unpoison_shadow(object, size);
	353	kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start,
	354	KASAN_KMALLOC_REDZONE);
	355	}
	356	EXPORT_SYMBOL(kasan_kmalloc);
	357
	358	void kasan_kmalloc_large(const void *ptr, size_t size)
	359	{
	360	struct page *page;
	361	unsigned long redzone_start;
	362	unsigned long redzone_end;
	363
	364	if (unlikely(ptr == NULL))
	365	return;
	366
367	page = virt_to_page(ptr);
368	redzone_start = round_up((unsigned long)(ptr + size),
369	KASAN_SHADOW_SCALE_SIZE);
370	redzone_end = (unsigned long)ptr + (PAGE_SIZE << compound_order(page));
371
372	kasan_unpoison_shadow(ptr, size);
373	kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start,
374	KASAN_PAGE_REDZONE);
375	}
376
377	void kasan_krealloc(const void *object, size_t size)
378	{
379	struct page *page;
380
381	if (unlikely(object == ZERO_SIZE_PTR))
382	return;
383
384	page = virt_to_head_page(object);
385
386	if (unlikely(!PageSlab(page)))
387	kasan_kmalloc_large(object, size);
388	else
389	kasan_kmalloc(page->slab_cache, object, size);
390	}
391
92393615 AR	392	void kasan_kfree(void *ptr)
	393	{
	394	struct page *page;
	395
	396	page = virt_to_head_page(ptr);
	397
	398	if (unlikely(!PageSlab(page)))
	399	kasan_poison_shadow(ptr, PAGE_SIZE << compound_order(page),
	400	KASAN_FREE_PAGE);
	401	else
	402	kasan_slab_free(page->slab_cache, ptr);
	403	}
	404
0316bec2 AR	405	void kasan_kfree_large(const void *ptr)
	406	{
	407	struct page *page = virt_to_page(ptr);
	408
	409	kasan_poison_shadow(ptr, PAGE_SIZE << compound_order(page),
	410	KASAN_FREE_PAGE);
	411	}
	412
bebf56a1 AR	413	int kasan_module_alloc(void *addr, size_t size)
	414	{
	415	void *ret;
	416	size_t shadow_size;
	417	unsigned long shadow_start;
	418
	419	shadow_start = (unsigned long)kasan_mem_to_shadow(addr);
	420	shadow_size = round_up(size >> KASAN_SHADOW_SCALE_SHIFT,
	421	PAGE_SIZE);
	422
	423	if (WARN_ON(!PAGE_ALIGNED(shadow_start)))
	424	return -EINVAL;
	425
	426	ret = __vmalloc_node_range(shadow_size, 1, shadow_start,
	427	shadow_start + shadow_size,
	428	GFP_KERNEL \| __GFP_HIGHMEM \| __GFP_ZERO,
	429	PAGE_KERNEL, VM_NO_GUARD, NUMA_NO_NODE,
	430	__builtin_return_address(0));
a5af5aa8 AR	431
	432	if (ret) {
	433	find_vm_area(addr)->flags \|= VM_KASAN;
	434	return 0;
	435	}
	436
	437	return -ENOMEM;
bebf56a1 AR	438	}
bebf56a1 AR	439
a5af5aa8	440	void kasan_free_shadow(const struct vm_struct *vm)
bebf56a1	441	{
a5af5aa8 AR	442	if (vm->flags & VM_KASAN)
a5af5aa8 AR	443	vfree(kasan_mem_to_shadow(vm->addr));
bebf56a1 AR	444	}
	445
	446	static void register_global(struct kasan_global *global)
	447	{
	448	size_t aligned_size = round_up(global->size, KASAN_SHADOW_SCALE_SIZE);
	449
	450	kasan_unpoison_shadow(global->beg, global->size);
	451
	452	kasan_poison_shadow(global->beg + aligned_size,
	453	global->size_with_redzone - aligned_size,
	454	KASAN_GLOBAL_REDZONE);
	455	}
	456
	457	void __asan_register_globals(struct kasan_global *globals, size_t size)
	458	{
	459	int i;
	460
	461	for (i = 0; i < size; i++)
	462	register_global(&globals[i]);
	463	}
	464	EXPORT_SYMBOL(__asan_register_globals);
	465
	466	void __asan_unregister_globals(struct kasan_global *globals, size_t size)
	467	{
	468	}
	469	EXPORT_SYMBOL(__asan_unregister_globals);
	470
0b24becc AR	471	#define DEFINE_ASAN_LOAD_STORE(size) \
	472	void __asan_load##size(unsigned long addr) \
	473	{ \
	474	check_memory_region(addr, size, false); \
	475	} \
	476	EXPORT_SYMBOL(__asan_load##size); \
	477	__alias(__asan_load##size) \
	478	void __asan_load##size##_noabort(unsigned long); \
	479	EXPORT_SYMBOL(__asan_load##size##_noabort); \
	480	void __asan_store##size(unsigned long addr) \
	481	{ \
	482	check_memory_region(addr, size, true); \
	483	} \
	484	EXPORT_SYMBOL(__asan_store##size); \
	485	__alias(__asan_store##size) \
	486	void __asan_store##size##_noabort(unsigned long); \
	487	EXPORT_SYMBOL(__asan_store##size##_noabort)
	488
	489	DEFINE_ASAN_LOAD_STORE(1);
	490	DEFINE_ASAN_LOAD_STORE(2);
	491	DEFINE_ASAN_LOAD_STORE(4);
	492	DEFINE_ASAN_LOAD_STORE(8);
	493	DEFINE_ASAN_LOAD_STORE(16);
	494
	495	void __asan_loadN(unsigned long addr, size_t size)
	496	{
	497	check_memory_region(addr, size, false);
	498	}
	499	EXPORT_SYMBOL(__asan_loadN);
	500
	501	__alias(__asan_loadN)
	502	void __asan_loadN_noabort(unsigned long, size_t);
	503	EXPORT_SYMBOL(__asan_loadN_noabort);
	504
	505	void __asan_storeN(unsigned long addr, size_t size)
	506	{
	507	check_memory_region(addr, size, true);
	508	}
	509	EXPORT_SYMBOL(__asan_storeN);
	510
	511	__alias(__asan_storeN)
	512	void __asan_storeN_noabort(unsigned long, size_t);
	513	EXPORT_SYMBOL(__asan_storeN_noabort);
	514
	515	/* to shut up compiler complaints */
	516	void __asan_handle_no_return(void) {}
	517	EXPORT_SYMBOL(__asan_handle_no_return);
786a8959 AR	518
	519	#ifdef CONFIG_MEMORY_HOTPLUG
	520	static int kasan_mem_notifier(struct notifier_block *nb,
	521	unsigned long action, void *data)
	522	{
	523	return (action == MEM_GOING_ONLINE) ? NOTIFY_BAD : NOTIFY_OK;
	524	}
	525
	526	static int __init kasan_memhotplug_init(void)
	527	{
	528	pr_err("WARNING: KASan doesn't support memory hot-add\n");
	529	pr_err("Memory hot-add will be disabled\n");
	530
	531	hotplug_memory_notifier(kasan_mem_notifier, 0);
	532
	533	return 0;
	534	}
	535
	536	module_init(kasan_memhotplug_init);
	537	#endif