On Sun, Jun 20, 2021 at 2:48 PM Kuan-Ying Lee
<Kuan-Ying.Lee@xxxxxxxxxxxx> wrote:
>
> 1. Move kasan_get_free_track() and kasan_set_free_info()
> into tags.c
Please mention that the patch doesn't only move but also combines
these functions for SW_TAGS and HW_TAGS modes.
> --- /dev/null
> +++ b/mm/kasan/report_tags.h
> @@ -0,0 +1,55 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (c) 2014 Samsung Electronics Co., Ltd.
> + * Copyright (c) 2020 Google, Inc.
> + */
> +#ifndef __MM_KASAN_REPORT_TAGS_H
> +#define __MM_KASAN_REPORT_TAGS_H
> +
> +#include "kasan.h"
> +#include "../slab.h"
> +
> +const char *kasan_get_bug_type(struct kasan_access_info *info)
As mentioned by Alex, don't put this implementation into a header. Put
it into report_tags.c. The declaration is already in kasan.h.
> +{
> +#ifdef CONFIG_KASAN_TAGS_IDENTIFY
> + struct kasan_alloc_meta *alloc_meta;
> + struct kmem_cache *cache;
> + struct page *page;
> + const void *addr;
> + void *object;
> + u8 tag;
> + int i;
> +
> + tag = get_tag(info->access_addr);
> + addr = kasan_reset_tag(info->access_addr);
> + page = kasan_addr_to_page(addr);
> + if (page && PageSlab(page)) {
> + cache = page->slab_cache;
> + object = nearest_obj(cache, page, (void *)addr);
> + alloc_meta = kasan_get_alloc_meta(cache, object);
> +
> + if (alloc_meta) {
> + for (i = 0; i < KASAN_NR_FREE_STACKS; i++) {
> + if (alloc_meta->free_pointer_tag[i] == tag)
> + return "use-after-free";
> + }
> + }
> + return "out-of-bounds";
> + }
> +#endif
> +
> + /*
> + * If access_size is a negative number, then it has reason to be
> + * defined as out-of-bounds bug type.
> + *
> + * Casting negative numbers to size_t would indeed turn up as
> + * a large size_t and its value will be larger than ULONG_MAX/2,
> + * so that this can qualify as out-of-bounds.
> + */
> + if (info->access_addr + info->access_size < info->access_addr)
> + return "out-of-bounds";
> +
> + return "invalid-access";
> +}
