aboutsummaryrefslogtreecommitdiff
path: root/kernel/sysctl-test.c
blob: 664ded05dd7a1969df37b42a857fd7e178b828ce (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
// SPDX-License-Identifier: GPL-2.0
/*
 * KUnit test of proc sysctl.
 */

#include <kunit/test.h>
#include <linux/sysctl.h>

#define KUNIT_PROC_READ 0
#define KUNIT_PROC_WRITE 1

static int i_zero;
static int i_one_hundred = 100;

/*
 * Test that proc_dointvec will not try to use a NULL .data field even when the
 * length is non-zero.
 */
static void sysctl_test_api_dointvec_null_tbl_data(struct kunit *test)
{
	struct ctl_table null_data_table = {
		.procname = "foo",
		/*
		 * Here we are testing that proc_dointvec behaves correctly when
		 * we give it a NULL .data field. Normally this would point to a
		 * piece of memory where the value would be stored.
		 */
		.data		= NULL,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec,
		.extra1		= &i_zero,
		.extra2         = &i_one_hundred,
	};
	/*
	 * proc_dointvec expects a buffer in user space, so we allocate one. We
	 * also need to cast it to __user so sparse doesn't get mad.
	 */
	void __user *buffer = (void __user *)kunit_kzalloc(test, sizeof(int),
							   GFP_USER);
	size_t len;
	loff_t pos;

	/*
	 * We don't care what the starting length is since proc_dointvec should
	 * not try to read because .data is NULL.
	 */
	len = 1234;
	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&null_data_table,
					       KUNIT_PROC_READ, buffer, &len,
					       &pos));
	KUNIT_EXPECT_EQ(test, 0, len);

	/*
	 * See above.
	 */
	len = 1234;
	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&null_data_table,
					       KUNIT_PROC_WRITE, buffer, &len,
					       &pos));
	KUNIT_EXPECT_EQ(test, 0, len);
}

/*
 * Similar to the previous test, we create a struct ctrl_table that has a .data
 * field that proc_dointvec cannot do anything with; however, this time it is
 * because we tell proc_dointvec that the size is 0.
 */
static void sysctl_test_api_dointvec_table_maxlen_unset(struct kunit *test)
{
	int data = 0;
	struct ctl_table data_maxlen_unset_table = {
		.procname = "foo",
		.data		= &data,
		/*
		 * So .data is no longer NULL, but we tell proc_dointvec its
		 * length is 0, so it still shouldn't try to use it.
		 */
		.maxlen		= 0,
		.mode		= 0644,
		.proc_handler	= proc_dointvec,
		.extra1		= &i_zero,
		.extra2         = &i_one_hundred,
	};
	void __user *buffer = (void __user *)kunit_kzalloc(test, sizeof(int),
							   GFP_USER);
	size_t len;
	loff_t pos;

	/*
	 * As before, we don't care what buffer length is because proc_dointvec
	 * cannot do anything because its internal .data buffer has zero length.
	 */
	len = 1234;
	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&data_maxlen_unset_table,
					       KUNIT_PROC_READ, buffer, &len,
					       &pos));
	KUNIT_EXPECT_EQ(test, 0, len);

	/*
	 * See previous comment.
	 */
	len = 1234;
	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&data_maxlen_unset_table,
					       KUNIT_PROC_WRITE, buffer, &len,
					       &pos));
	KUNIT_EXPECT_EQ(test, 0, len);
}

/*
 * Here we provide a valid struct ctl_table, but we try to read and write from
 * it using a buffer of zero length, so it should still fail in a similar way as
 * before.
 */
static void sysctl_test_api_dointvec_table_len_is_zero(struct kunit *test)
{
	int data = 0;
	/* Good table. */
	struct ctl_table table = {
		.procname = "foo",
		.data		= &data,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec,
		.extra1		= &i_zero,
		.extra2         = &i_one_hundred,
	};
	void __user *buffer = (void __user *)kunit_kzalloc(test, sizeof(int),
							   GFP_USER);
	/*
	 * However, now our read/write buffer has zero length.
	 */
	size_t len = 0;
	loff_t pos;

	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_READ, buffer,
					       &len, &pos));
	KUNIT_EXPECT_EQ(test, 0, len);

	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_WRITE, buffer,
					       &len, &pos));
	KUNIT_EXPECT_EQ(test, 0, len);
}

/*
 * Test that proc_dointvec refuses to read when the file position is non-zero.
 */
static void sysctl_test_api_dointvec_table_read_but_position_set(
		struct kunit *test)
{
	int data = 0;
	/* Good table. */
	struct ctl_table table = {
		.procname = "foo",
		.data		= &data,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec,
		.extra1		= &i_zero,
		.extra2         = &i_one_hundred,
	};
	void __user *buffer = (void __user *)kunit_kzalloc(test, sizeof(int),
							   GFP_USER);
	/*
	 * We don't care about our buffer length because we start off with a
	 * non-zero file position.
	 */
	size_t len = 1234;
	/*
	 * proc_dointvec should refuse to read into the buffer since the file
	 * pos is non-zero.
	 */
	loff_t pos = 1;

	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_READ, buffer,
					       &len, &pos));
	KUNIT_EXPECT_EQ(test, 0, len);
}

/*
 * Test that we can read a two digit number in a sufficiently size buffer.
 * Nothing fancy.
 */
static void sysctl_test_dointvec_read_happy_single_positive(struct kunit *test)
{
	int data = 0;
	/* Good table. */
	struct ctl_table table = {
		.procname = "foo",
		.data		= &data,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec,
		.extra1		= &i_zero,
		.extra2         = &i_one_hundred,
	};
	size_t len = 4;
	loff_t pos = 0;
	char *buffer = kunit_kzalloc(test, len, GFP_USER);
	char __user *user_buffer = (char __user *)buffer;
	/* Store 13 in the data field. */
	*((int *)table.data) = 13;

	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_READ,
					       user_buffer, &len, &pos));
	KUNIT_ASSERT_EQ(test, 3, len);
	buffer[len] = '\0';
	/* And we read 13 back out. */
	KUNIT_EXPECT_STREQ(test, "13\n", buffer);
}

/*
 * Same as previous test, just now with negative numbers.
 */
static void sysctl_test_dointvec_read_happy_single_negative(struct kunit *test)
{
	int data = 0;
	/* Good table. */
	struct ctl_table table = {
		.procname = "foo",
		.data		= &data,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec,
		.extra1		= &i_zero,
		.extra2         = &i_one_hundred,
	};
	size_t len = 5;
	loff_t pos = 0;
	char *buffer = kunit_kzalloc(test, len, GFP_USER);
	char __user *user_buffer = (char __user *)buffer;
	*((int *)table.data) = -16;

	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_READ,
					       user_buffer, &len, &pos));
	KUNIT_ASSERT_EQ(test, 4, len);
	buffer[len] = '\0';
	KUNIT_EXPECT_STREQ(test, "-16\n", buffer);
}

/*
 * Test that a simple positive write works.
 */
static void sysctl_test_dointvec_write_happy_single_positive(struct kunit *test)
{
	int data = 0;
	/* Good table. */
	struct ctl_table table = {
		.procname = "foo",
		.data		= &data,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec,
		.extra1		= &i_zero,
		.extra2         = &i_one_hundred,
	};
	char input[] = "9";
	size_t len = sizeof(input) - 1;
	loff_t pos = 0;
	char *buffer = kunit_kzalloc(test, len, GFP_USER);
	char __user *user_buffer = (char __user *)buffer;

	memcpy(buffer, input, len);

	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_WRITE,
					       user_buffer, &len, &pos));
	KUNIT_EXPECT_EQ(test, sizeof(input) - 1, len);
	KUNIT_EXPECT_EQ(test, sizeof(input) - 1, pos);
	KUNIT_EXPECT_EQ(test, 9, *((int *)table.data));
}

/*
 * Same as previous test, but now with negative numbers.
 */
static void sysctl_test_dointvec_write_happy_single_negative(struct kunit *test)
{
	int data = 0;
	struct ctl_table table = {
		.procname = "foo",
		.data		= &data,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec,
		.extra1		= &i_zero,
		.extra2         = &i_one_hundred,
	};
	char input[] = "-9";
	size_t len = sizeof(input) - 1;
	loff_t pos = 0;
	char *buffer = kunit_kzalloc(test, len, GFP_USER);
	char __user *user_buffer = (char __user *)buffer;

	memcpy(buffer, input, len);

	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_WRITE,
					       user_buffer, &len, &pos));
	KUNIT_EXPECT_EQ(test, sizeof(input) - 1, len);
	KUNIT_EXPECT_EQ(test, sizeof(input) - 1, pos);
	KUNIT_EXPECT_EQ(test, -9, *((int *)table.data));
}

/*
 * Test that writing a value smaller than the minimum possible value is not
 * allowed.
 */
static void sysctl_test_api_dointvec_write_single_less_int_min(
		struct kunit *test)
{
	int data = 0;
	struct ctl_table table = {
		.procname = "foo",
		.data		= &data,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec,
		.extra1		= &i_zero,
		.extra2         = &i_one_hundred,
	};
	size_t max_len = 32, len = max_len;
	loff_t pos = 0;
	char *buffer = kunit_kzalloc(test, max_len, GFP_USER);
	char __user *user_buffer = (char __user *)buffer;
	unsigned long abs_of_less_than_min = (unsigned long)INT_MAX
					     - (INT_MAX + INT_MIN) + 1;

	/*
	 * We use this rigmarole to create a string that contains a value one
	 * less than the minimum accepted value.
	 */
	KUNIT_ASSERT_LT(test,
			(size_t)snprintf(buffer, max_len, "-%lu",
					 abs_of_less_than_min),
			max_len);

	KUNIT_EXPECT_EQ(test, -EINVAL, proc_dointvec(&table, KUNIT_PROC_WRITE,
						     user_buffer, &len, &pos));
	KUNIT_EXPECT_EQ(test, max_len, len);
	KUNIT_EXPECT_EQ(test, 0, *((int *)table.data));
}

/*
 * Test that writing the maximum possible value works.
 */
static void sysctl_test_api_dointvec_write_single_greater_int_max(
		struct kunit *test)
{
	int data = 0;
	struct ctl_table table = {
		.procname = "foo",
		.data		= &data,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec,
		.extra1		= &i_zero,
		.extra2         = &i_one_hundred,
	};
	size_t max_len = 32, len = max_len;
	loff_t pos = 0;
	char *buffer = kunit_kzalloc(test, max_len, GFP_USER);
	char __user *user_buffer = (char __user *)buffer;
	unsigned long greater_than_max = (unsigned long)INT_MAX + 1;

	KUNIT_ASSERT_GT(test, greater_than_max, (unsigned long)INT_MAX);
	KUNIT_ASSERT_LT(test, (size_t)snprintf(buffer, max_len, "%lu",
					       greater_than_max),
			max_len);
	KUNIT_EXPECT_EQ(test, -EINVAL, proc_dointvec(&table, KUNIT_PROC_WRITE,
						     user_buffer, &len, &pos));
	KUNIT_ASSERT_EQ(test, max_len, len);
	KUNIT_EXPECT_EQ(test, 0, *((int *)table.data));
}

static struct kunit_case sysctl_test_cases[] = {
	KUNIT_CASE(sysctl_test_api_dointvec_null_tbl_data),
	KUNIT_CASE(sysctl_test_api_dointvec_table_maxlen_unset),
	KUNIT_CASE(sysctl_test_api_dointvec_table_len_is_zero),
	KUNIT_CASE(sysctl_test_api_dointvec_table_read_but_position_set),
	KUNIT_CASE(sysctl_test_dointvec_read_happy_single_positive),
	KUNIT_CASE(sysctl_test_dointvec_read_happy_single_negative),
	KUNIT_CASE(sysctl_test_dointvec_write_happy_single_positive),
	KUNIT_CASE(sysctl_test_dointvec_write_happy_single_negative),
	KUNIT_CASE(sysctl_test_api_dointvec_write_single_less_int_min),
	KUNIT_CASE(sysctl_test_api_dointvec_write_single_greater_int_max),
	{}
};

static struct kunit_suite sysctl_test_suite = {
	.name = "sysctl_test",
	.test_cases = sysctl_test_cases,
};

kunit_test_suites(&sysctl_test_suite);

MODULE_LICENSE("GPL v2");