1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * This file contains software tag-based KASAN specific error reporting code. |
4 | * |
5 | * Copyright (c) 2014 Samsung Electronics Co., Ltd. |
6 | * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com> |
7 | * |
8 | * Some code borrowed from https://github.com/xairy/kasan-prototype by |
9 | * Andrey Konovalov <andreyknvl@gmail.com> |
10 | */ |
11 | |
12 | #include <linux/bitops.h> |
13 | #include <linux/ftrace.h> |
14 | #include <linux/init.h> |
15 | #include <linux/kernel.h> |
16 | #include <linux/mm.h> |
17 | #include <linux/printk.h> |
18 | #include <linux/sched.h> |
19 | #include <linux/sched/task_stack.h> |
20 | #include <linux/slab.h> |
21 | #include <linux/stackdepot.h> |
22 | #include <linux/stacktrace.h> |
23 | #include <linux/string.h> |
24 | #include <linux/types.h> |
25 | #include <linux/kasan.h> |
26 | #include <linux/module.h> |
27 | |
28 | #include <asm/sections.h> |
29 | |
30 | #include "kasan.h" |
31 | #include "../slab.h" |
32 | |
33 | const void *kasan_find_first_bad_addr(const void *addr, size_t size) |
34 | { |
35 | u8 tag = get_tag(addr); |
36 | void *p = kasan_reset_tag(addr); |
37 | void *end = p + size; |
38 | |
39 | if (!addr_has_metadata(addr: p)) |
40 | return p; |
41 | |
42 | while (p < end && tag == *(u8 *)kasan_mem_to_shadow(p)) |
43 | p += KASAN_GRANULE_SIZE; |
44 | |
45 | return p; |
46 | } |
47 | |
48 | size_t kasan_get_alloc_size(void *object, struct kmem_cache *cache) |
49 | { |
50 | size_t size = 0; |
51 | u8 *shadow; |
52 | |
53 | /* |
54 | * Skip the addr_has_metadata check, as this function only operates on |
55 | * slab memory, which must have metadata. |
56 | */ |
57 | |
58 | /* |
59 | * The loop below returns 0 for freed objects, for which KASAN cannot |
60 | * calculate the allocation size based on the metadata. |
61 | */ |
62 | shadow = (u8 *)kasan_mem_to_shadow(object); |
63 | while (size < cache->object_size) { |
64 | if (*shadow != KASAN_TAG_INVALID) |
65 | size += KASAN_GRANULE_SIZE; |
66 | else |
67 | return size; |
68 | shadow++; |
69 | } |
70 | |
71 | return cache->object_size; |
72 | } |
73 | |
74 | void kasan_metadata_fetch_row(char *buffer, void *row) |
75 | { |
76 | memcpy(buffer, kasan_mem_to_shadow(row), META_BYTES_PER_ROW); |
77 | } |
78 | |
79 | void kasan_print_tags(u8 addr_tag, const void *addr) |
80 | { |
81 | u8 *shadow = (u8 *)kasan_mem_to_shadow(addr); |
82 | |
83 | pr_err("Pointer tag: [%02x], memory tag: [%02x]\n" , addr_tag, *shadow); |
84 | } |
85 | |
86 | #ifdef CONFIG_KASAN_STACK |
87 | void kasan_print_address_stack_frame(const void *addr) |
88 | { |
89 | if (WARN_ON(!object_is_on_stack(addr))) |
90 | return; |
91 | |
92 | pr_err("The buggy address belongs to stack of task %s/%d\n" , |
93 | current->comm, task_pid_nr(current)); |
94 | } |
95 | #endif |
96 | |