// SPDX-License-Identifier: GPL-2.0
/*
 * This file contains software tag-based KASAN specific error reporting 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>
 */

#include <linux/bitops.h>
#include <linux/ftrace.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/printk.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/slab.h>
#include <linux/stackdepot.h>
#include <linux/stacktrace.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/kasan.h>
#include <linux/module.h>

#include <asm/sections.h>

#include "kasan.h"
#include "../slab.h"

const void *kasan_find_first_bad_addr(const void *addr, size_t size)
{
        u8 tag = get_tag(addr);
        void *p = kasan_reset_tag(addr);
        void *end = p + size;

        if (!addr_has_metadata(p))
                return p;

        while (p < end && tag == *(u8 *)kasan_mem_to_shadow(p))
                p += KASAN_GRANULE_SIZE;

        return p;
}

size_t kasan_get_alloc_size(void *object, struct kmem_cache *cache)
{
        size_t size = 0;
        u8 *shadow;

        /*
         * Skip the addr_has_metadata check, as this function only operates on
         * slab memory, which must have metadata.
         */

        /*
         * The loop below returns 0 for freed objects, for which KASAN cannot
         * calculate the allocation size based on the metadata.
         */
        shadow = (u8 *)kasan_mem_to_shadow(object);
        while (size < cache->object_size) {
                if (*shadow != KASAN_TAG_INVALID)
                        size += KASAN_GRANULE_SIZE;
                else
                        return size;
                shadow++;
        }

        return cache->object_size;
}

void kasan_metadata_fetch_row(char *buffer, void *row)
{
        memcpy(buffer, kasan_mem_to_shadow(row), META_BYTES_PER_ROW);
}

void kasan_print_tags(u8 addr_tag, const void *addr)
{
        u8 *shadow = (u8 *)kasan_mem_to_shadow(addr);

        pr_err("Pointer tag: [%02x], memory tag: [%02x]\n", addr_tag, *shadow);
}

#ifdef CONFIG_KASAN_STACK
void kasan_print_address_stack_frame(const void *addr)
{
        if (WARN_ON(!object_is_on_stack(addr)))
                return;

        pr_err("The buggy address belongs to stack of task %s/%d\n",
               current->comm, task_pid_nr(current));
}
#endif