72 lines
1.7 KiB
C
72 lines
1.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* This file contains hardware tag-based KASAN specific error reporting code.
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*
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* Copyright (c) 2020 Google, Inc.
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* Author: Andrey Konovalov <andreyknvl@google.com>
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*/
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#include <linux/kasan.h>
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#include <linux/kernel.h>
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#include <linux/memory.h>
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#include <linux/mm.h>
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#include <linux/string.h>
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#include <linux/types.h>
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#include "kasan.h"
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const void *kasan_find_first_bad_addr(const void *addr, size_t size)
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{
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/*
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* Hardware Tag-Based KASAN only calls this function for normal memory
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* accesses, and thus addr points precisely to the first bad address
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* with an invalid (and present) memory tag. Therefore:
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* 1. Return the address as is without walking memory tags.
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* 2. Skip the addr_has_metadata check.
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*/
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return kasan_reset_tag(addr);
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}
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size_t kasan_get_alloc_size(void *object, struct kmem_cache *cache)
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{
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size_t size = 0;
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int i = 0;
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u8 memory_tag;
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/*
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* Skip the addr_has_metadata check, as this function only operates on
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* slab memory, which must have metadata.
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*/
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/*
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* The loop below returns 0 for freed objects, for which KASAN cannot
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* calculate the allocation size based on the metadata.
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*/
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while (size < cache->object_size) {
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memory_tag = hw_get_mem_tag(object + i * KASAN_GRANULE_SIZE);
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if (memory_tag != KASAN_TAG_INVALID)
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size += KASAN_GRANULE_SIZE;
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else
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return size;
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i++;
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}
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return cache->object_size;
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}
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void kasan_metadata_fetch_row(char *buffer, void *row)
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{
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int i;
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for (i = 0; i < META_BYTES_PER_ROW; i++)
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buffer[i] = hw_get_mem_tag(row + i * KASAN_GRANULE_SIZE);
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}
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void kasan_print_tags(u8 addr_tag, const void *addr)
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{
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u8 memory_tag = hw_get_mem_tag((void *)addr);
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pr_err("Pointer tag: [%02x], memory tag: [%02x]\n",
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addr_tag, memory_tag);
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}
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