// 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 <linux/export.h>
#include <linux/init.h>
#include <linux/kasan.h>
#include <linux/kernel.h>
#include <linux/kmemleak.h>
#include <linux/linkage.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/sched/task_stack.h>
#include <linux/slab.h>
#include <linux/stacktrace.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/vmalloc.h>
#include <linux/bug.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#include "kasan.h"
#include "../slab.h"
static inline depot_stack_handle_t save_stack(gfp_t flags)
{
unsigned long entries[KASAN_STACK_DEPTH];
unsigned int nr_entries;
nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 0);
nr_entries = filter_irq_stacks(entries, nr_entries);
return stack_depot_save(entries, nr_entries, flags);
}
static inline void set_track(struct kasan_track *track, gfp_t flags)
{
track->pid = current->pid;
track->stack = save_stack(flags);
}
void kasan_enable_current(void)
{
current->kasan_depth++;
}
void kasan_disable_current(void)
{
current->kasan_depth--;
}
bool __kasan_check_read(const volatile void *p, unsigned int size)
{
return check_memory_region((unsigned long)p, size, false, _RET_IP_);
}
EXPORT_SYMBOL(__kasan_check_read);
bool __kasan_check_write(const volatile void *p, unsigned int size)
{
return check_memory_region((unsigned long)p, size, true, _RET_IP_);
}
EXPORT_SYMBOL(__kasan_check_write);
#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;
}
}
static void __kasan_unpoison_stack(struct task_struct *task, const void *sp)
{
void *base = task_stack_page(task);
size_t size = sp - base;
kasan_unpoison_shadow(base, size);
}
/* Unpoison the entire stack for a task. */
void kasan_unpoison_task_stack(struct task_struct *task)
{
__kasan_unpoison_stack(task, task_stack_page(task) + THREAD_SIZE);
}
/* Unpoison the stack for the current task