1/*
2 *
3 * Copyright (c) 2014 Samsung Electronics Co., Ltd.
4 * Author: Andrey Ryabinin <a.ryabinin@samsung.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 */
11
12#define pr_fmt(fmt) "kasan test: %s " fmt, __func__
13
14#include <linux/kernel.h>
15#include <linux/printk.h>
16#include <linux/slab.h>
17#include <linux/string.h>
18#include <linux/module.h>
19
20static noinline void __init kmalloc_oob_right(void)
21{
22	char *ptr;
23	size_t size = 123;
24
25	pr_info("out-of-bounds to right\n");
26	ptr = kmalloc(size, GFP_KERNEL);
27	if (!ptr) {
28		pr_err("Allocation failed\n");
29		return;
30	}
31
32	ptr[size] = 'x';
33	kfree(ptr);
34}
35
36static noinline void __init kmalloc_oob_left(void)
37{
38	char *ptr;
39	size_t size = 15;
40
41	pr_info("out-of-bounds to left\n");
42	ptr = kmalloc(size, GFP_KERNEL);
43	if (!ptr) {
44		pr_err("Allocation failed\n");
45		return;
46	}
47
48	*ptr = *(ptr - 1);
49	kfree(ptr);
50}
51
52static noinline void __init kmalloc_node_oob_right(void)
53{
54	char *ptr;
55	size_t size = 4096;
56
57	pr_info("kmalloc_node(): out-of-bounds to right\n");
58	ptr = kmalloc_node(size, GFP_KERNEL, 0);
59	if (!ptr) {
60		pr_err("Allocation failed\n");
61		return;
62	}
63
64	ptr[size] = 0;
65	kfree(ptr);
66}
67
68static noinline void __init kmalloc_large_oob_rigth(void)
69{
70	char *ptr;
71	size_t size = KMALLOC_MAX_CACHE_SIZE + 10;
72
73	pr_info("kmalloc large allocation: out-of-bounds to right\n");
74	ptr = kmalloc(size, GFP_KERNEL);
75	if (!ptr) {
76		pr_err("Allocation failed\n");
77		return;
78	}
79
80	ptr[size] = 0;
81	kfree(ptr);
82}
83
84static noinline void __init kmalloc_oob_krealloc_more(void)
85{
86	char *ptr1, *ptr2;
87	size_t size1 = 17;
88	size_t size2 = 19;
89
90	pr_info("out-of-bounds after krealloc more\n");
91	ptr1 = kmalloc(size1, GFP_KERNEL);
92	ptr2 = krealloc(ptr1, size2, GFP_KERNEL);
93	if (!ptr1 || !ptr2) {
94		pr_err("Allocation failed\n");
95		kfree(ptr1);
96		return;
97	}
98
99	ptr2[size2] = 'x';
100	kfree(ptr2);
101}
102
103static noinline void __init kmalloc_oob_krealloc_less(void)
104{
105	char *ptr1, *ptr2;
106	size_t size1 = 17;
107	size_t size2 = 15;
108
109	pr_info("out-of-bounds after krealloc less\n");
110	ptr1 = kmalloc(size1, GFP_KERNEL);
111	ptr2 = krealloc(ptr1, size2, GFP_KERNEL);
112	if (!ptr1 || !ptr2) {
113		pr_err("Allocation failed\n");
114		kfree(ptr1);
115		return;
116	}
117	ptr2[size1] = 'x';
118	kfree(ptr2);
119}
120
121static noinline void __init kmalloc_oob_16(void)
122{
123	struct {
124		u64 words[2];
125	} *ptr1, *ptr2;
126
127	pr_info("kmalloc out-of-bounds for 16-bytes access\n");
128	ptr1 = kmalloc(sizeof(*ptr1) - 3, GFP_KERNEL);
129	ptr2 = kmalloc(sizeof(*ptr2), GFP_KERNEL);
130	if (!ptr1 || !ptr2) {
131		pr_err("Allocation failed\n");
132		kfree(ptr1);
133		kfree(ptr2);
134		return;
135	}
136	*ptr1 = *ptr2;
137	kfree(ptr1);
138	kfree(ptr2);
139}
140
141static noinline void __init kmalloc_oob_in_memset(void)
142{
143	char *ptr;
144	size_t size = 666;
145
146	pr_info("out-of-bounds in memset\n");
147	ptr = kmalloc(size, GFP_KERNEL);
148	if (!ptr) {
149		pr_err("Allocation failed\n");
150		return;
151	}
152
153	memset(ptr, 0, size+5);
154	kfree(ptr);
155}
156
157static noinline void __init kmalloc_uaf(void)
158{
159	char *ptr;
160	size_t size = 10;
161
162	pr_info("use-after-free\n");
163	ptr = kmalloc(size, GFP_KERNEL);
164	if (!ptr) {
165		pr_err("Allocation failed\n");
166		return;
167	}
168
169	kfree(ptr);
170	*(ptr + 8) = 'x';
171}
172
173static noinline void __init kmalloc_uaf_memset(void)
174{
175	char *ptr;
176	size_t size = 33;
177
178	pr_info("use-after-free in memset\n");
179	ptr = kmalloc(size, GFP_KERNEL);
180	if (!ptr) {
181		pr_err("Allocation failed\n");
182		return;
183	}
184
185	kfree(ptr);
186	memset(ptr, 0, size);
187}
188
189static noinline void __init kmalloc_uaf2(void)
190{
191	char *ptr1, *ptr2;
192	size_t size = 43;
193
194	pr_info("use-after-free after another kmalloc\n");
195	ptr1 = kmalloc(size, GFP_KERNEL);
196	if (!ptr1) {
197		pr_err("Allocation failed\n");
198		return;
199	}
200
201	kfree(ptr1);
202	ptr2 = kmalloc(size, GFP_KERNEL);
203	if (!ptr2) {
204		pr_err("Allocation failed\n");
205		return;
206	}
207
208	ptr1[40] = 'x';
209	kfree(ptr2);
210}
211
212static noinline void __init kmem_cache_oob(void)
213{
214	char *p;
215	size_t size = 200;
216	struct kmem_cache *cache = kmem_cache_create("test_cache",
217						size, 0,
218						0, NULL);
219	if (!cache) {
220		pr_err("Cache allocation failed\n");
221		return;
222	}
223	pr_info("out-of-bounds in kmem_cache_alloc\n");
224	p = kmem_cache_alloc(cache, GFP_KERNEL);
225	if (!p) {
226		pr_err("Allocation failed\n");
227		kmem_cache_destroy(cache);
228		return;
229	}
230
231	*p = p[size];
232	kmem_cache_free(cache, p);
233	kmem_cache_destroy(cache);
234}
235
236static char global_array[10];
237
238static noinline void __init kasan_global_oob(void)
239{
240	volatile int i = 3;
241	char *p = &global_array[ARRAY_SIZE(global_array) + i];
242
243	pr_info("out-of-bounds global variable\n");
244	*(volatile char *)p;
245}
246
247static noinline void __init kasan_stack_oob(void)
248{
249	char stack_array[10];
250	volatile int i = 0;
251	char *p = &stack_array[ARRAY_SIZE(stack_array) + i];
252
253	pr_info("out-of-bounds on stack\n");
254	*(volatile char *)p;
255}
256
257static int __init kmalloc_tests_init(void)
258{
259	kmalloc_oob_right();
260	kmalloc_oob_left();
261	kmalloc_node_oob_right();
262	kmalloc_large_oob_rigth();
263	kmalloc_oob_krealloc_more();
264	kmalloc_oob_krealloc_less();
265	kmalloc_oob_16();
266	kmalloc_oob_in_memset();
267	kmalloc_uaf();
268	kmalloc_uaf_memset();
269	kmalloc_uaf2();
270	kmem_cache_oob();
271	kasan_stack_oob();
272	kasan_global_oob();
273	return -EAGAIN;
274}
275
276module_init(kmalloc_tests_init);
277MODULE_LICENSE("GPL");
278