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// SPDX-License-Identifier: GPL-2.0
/*
* This file contains common generic and tag-based KASAN code.
*
* Copyright (c) 2014 Samsung Electronics Co., Ltd.
* Author: Andrey Ryabinin <ryabinin.a.a@gmail.com>
*
* Some code borrowed from https://github.com/xairy/kasan-prototype by
* Andrey Konovalov <andreyknvl@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.
*
*/
#include <common.h>
#include <linux/kasan.h>
#include <linux/kernel.h>
#include "kasan.h"
int kasan_depth;
void kasan_enable_current(void)
{
kasan_depth++;
}
void kasan_disable_current(void)
{
kasan_depth--;
}
#undef memset
void *memset(void *addr, int c, size_t len)
{
if (!check_memory_region((unsigned long)addr, len, true, _RET_IP_))
return NULL;
return __memset(addr, c, len);
}
#ifdef __HAVE_ARCH_MEMMOVE
#undef memmove
void *memmove(void *dest, const void *src, size_t len)
{
if (!check_memory_region((unsigned long)src, len, false, _RET_IP_) ||
!check_memory_region((unsigned long)dest, len, true, _RET_IP_))
return NULL;
return __memmove(dest, src, len);
}
#endif
#undef memcpy
void *memcpy(void *dest, const void *src, size_t len)
{
if (!check_memory_region((unsigned long)src, len, false, _RET_IP_) ||
!check_memory_region((unsigned long)dest, len, true, _RET_IP_))
return NULL;
return __memcpy(dest, src, len);
}
/*
* Poisons the shadow memory for 'size' bytes starting from 'addr'.
* Memory addresses should be aligned to KASAN_SHADOW_SCALE_SIZE.
*/
void kasan_poison_shadow(const void *address, size_t size, u8 value)
{
void *shadow_start, *shadow_end;
/*
* Perform shadow offset calculation based on untagged address, as
* some of the callers (e.g. kasan_poison_object_data) pass tagged
* addresses to this function.
*/
address = reset_tag(address);
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)
{
u8 tag = get_tag(address);
/*
* Perform shadow offset calculation based on untagged address, as
* some of the callers (e.g. kasan_unpoison_object_data) pass tagged
* addresses to this function.
*/
address = reset_tag(address);
kasan_poison_shadow(address, size, tag);
if (size & KASAN_SHADOW_MASK) {
u8 *shadow = (u8 *)kasan_mem_to_shadow(address + size);
if (IS_ENABLED(CONFIG_KASAN_SW_TAGS))
*shadow = tag;
else
*shadow = size & KASAN_SHADOW_MASK;
}
}
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