1// SPDX-License-Identifier: GPL-2.0
2/*
3 * KUnit test of proc sysctl.
4 */
5
6#include <kunit/test.h>
7#include <linux/sysctl.h>
8
9#define KUNIT_PROC_READ 0
10#define KUNIT_PROC_WRITE 1
11
12/*
13 * Test that proc_dointvec will not try to use a NULL .data field even when the
14 * length is non-zero.
15 */
16static void sysctl_test_api_dointvec_null_tbl_data(struct kunit *test)
17{
18 struct ctl_table null_data_table = {
19 .procname = "foo",
20 /*
21 * Here we are testing that proc_dointvec behaves correctly when
22 * we give it a NULL .data field. Normally this would point to a
23 * piece of memory where the value would be stored.
24 */
25 .data = NULL,
26 .maxlen = sizeof(int),
27 .mode = 0644,
28 .proc_handler = proc_dointvec,
29 .extra1 = SYSCTL_ZERO,
30 .extra2 = SYSCTL_ONE_HUNDRED,
31 };
32 /*
33 * proc_dointvec expects a buffer in user space, so we allocate one. We
34 * also need to cast it to __user so sparse doesn't get mad.
35 */
36 void __user *buffer = (void __user *)kunit_kzalloc(test, size: sizeof(int),
37 GFP_USER);
38 size_t len;
39 loff_t pos;
40
41 /*
42 * We don't care what the starting length is since proc_dointvec should
43 * not try to read because .data is NULL.
44 */
45 len = 1234;
46 KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&null_data_table,
47 KUNIT_PROC_READ, buffer, &len,
48 &pos));
49 KUNIT_EXPECT_EQ(test, 0, len);
50
51 /*
52 * See above.
53 */
54 len = 1234;
55 KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&null_data_table,
56 KUNIT_PROC_WRITE, buffer, &len,
57 &pos));
58 KUNIT_EXPECT_EQ(test, 0, len);
59}
60
61/*
62 * Similar to the previous test, we create a struct ctrl_table that has a .data
63 * field that proc_dointvec cannot do anything with; however, this time it is
64 * because we tell proc_dointvec that the size is 0.
65 */
66static void sysctl_test_api_dointvec_table_maxlen_unset(struct kunit *test)
67{
68 int data = 0;
69 struct ctl_table data_maxlen_unset_table = {
70 .procname = "foo",
71 .data = &data,
72 /*
73 * So .data is no longer NULL, but we tell proc_dointvec its
74 * length is 0, so it still shouldn't try to use it.
75 */
76 .maxlen = 0,
77 .mode = 0644,
78 .proc_handler = proc_dointvec,
79 .extra1 = SYSCTL_ZERO,
80 .extra2 = SYSCTL_ONE_HUNDRED,
81 };
82 void __user *buffer = (void __user *)kunit_kzalloc(test, size: sizeof(int),
83 GFP_USER);
84 size_t len;
85 loff_t pos;
86
87 /*
88 * As before, we don't care what buffer length is because proc_dointvec
89 * cannot do anything because its internal .data buffer has zero length.
90 */
91 len = 1234;
92 KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&data_maxlen_unset_table,
93 KUNIT_PROC_READ, buffer, &len,
94 &pos));
95 KUNIT_EXPECT_EQ(test, 0, len);
96
97 /*
98 * See previous comment.
99 */
100 len = 1234;
101 KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&data_maxlen_unset_table,
102 KUNIT_PROC_WRITE, buffer, &len,
103 &pos));
104 KUNIT_EXPECT_EQ(test, 0, len);
105}
106
107/*
108 * Here we provide a valid struct ctl_table, but we try to read and write from
109 * it using a buffer of zero length, so it should still fail in a similar way as
110 * before.
111 */
112static void sysctl_test_api_dointvec_table_len_is_zero(struct kunit *test)
113{
114 int data = 0;
115 /* Good table. */
116 struct ctl_table table = {
117 .procname = "foo",
118 .data = &data,
119 .maxlen = sizeof(int),
120 .mode = 0644,
121 .proc_handler = proc_dointvec,
122 .extra1 = SYSCTL_ZERO,
123 .extra2 = SYSCTL_ONE_HUNDRED,
124 };
125 void __user *buffer = (void __user *)kunit_kzalloc(test, size: sizeof(int),
126 GFP_USER);
127 /*
128 * However, now our read/write buffer has zero length.
129 */
130 size_t len = 0;
131 loff_t pos;
132
133 KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_READ, buffer,
134 &len, &pos));
135 KUNIT_EXPECT_EQ(test, 0, len);
136
137 KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_WRITE, buffer,
138 &len, &pos));
139 KUNIT_EXPECT_EQ(test, 0, len);
140}
141
142/*
143 * Test that proc_dointvec refuses to read when the file position is non-zero.
144 */
145static void sysctl_test_api_dointvec_table_read_but_position_set(
146 struct kunit *test)
147{
148 int data = 0;
149 /* Good table. */
150 struct ctl_table table = {
151 .procname = "foo",
152 .data = &data,
153 .maxlen = sizeof(int),
154 .mode = 0644,
155 .proc_handler = proc_dointvec,
156 .extra1 = SYSCTL_ZERO,
157 .extra2 = SYSCTL_ONE_HUNDRED,
158 };
159 void __user *buffer = (void __user *)kunit_kzalloc(test, size: sizeof(int),
160 GFP_USER);
161 /*
162 * We don't care about our buffer length because we start off with a
163 * non-zero file position.
164 */
165 size_t len = 1234;
166 /*
167 * proc_dointvec should refuse to read into the buffer since the file
168 * pos is non-zero.
169 */
170 loff_t pos = 1;
171
172 KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_READ, buffer,
173 &len, &pos));
174 KUNIT_EXPECT_EQ(test, 0, len);
175}
176
177/*
178 * Test that we can read a two digit number in a sufficiently size buffer.
179 * Nothing fancy.
180 */
181static void sysctl_test_dointvec_read_happy_single_positive(struct kunit *test)
182{
183 int data = 0;
184 /* Good table. */
185 struct ctl_table table = {
186 .procname = "foo",
187 .data = &data,
188 .maxlen = sizeof(int),
189 .mode = 0644,
190 .proc_handler = proc_dointvec,
191 .extra1 = SYSCTL_ZERO,
192 .extra2 = SYSCTL_ONE_HUNDRED,
193 };
194 size_t len = 4;
195 loff_t pos = 0;
196 char *buffer = kunit_kzalloc(test, size: len, GFP_USER);
197 char __user *user_buffer = (char __user *)buffer;
198 /* Store 13 in the data field. */
199 *((int *)table.data) = 13;
200
201 KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_READ,
202 user_buffer, &len, &pos));
203 KUNIT_ASSERT_EQ(test, 3, len);
204 buffer[len] = '\0';
205 /* And we read 13 back out. */
206 KUNIT_EXPECT_STREQ(test, "13\n", buffer);
207}
208
209/*
210 * Same as previous test, just now with negative numbers.
211 */
212static void sysctl_test_dointvec_read_happy_single_negative(struct kunit *test)
213{
214 int data = 0;
215 /* Good table. */
216 struct ctl_table table = {
217 .procname = "foo",
218 .data = &data,
219 .maxlen = sizeof(int),
220 .mode = 0644,
221 .proc_handler = proc_dointvec,
222 .extra1 = SYSCTL_ZERO,
223 .extra2 = SYSCTL_ONE_HUNDRED,
224 };
225 size_t len = 5;
226 loff_t pos = 0;
227 char *buffer = kunit_kzalloc(test, size: len, GFP_USER);
228 char __user *user_buffer = (char __user *)buffer;
229 *((int *)table.data) = -16;
230
231 KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_READ,
232 user_buffer, &len, &pos));
233 KUNIT_ASSERT_EQ(test, 4, len);
234 buffer[len] = '\0';
235 KUNIT_EXPECT_STREQ(test, "-16\n", buffer);
236}
237
238/*
239 * Test that a simple positive write works.
240 */
241static void sysctl_test_dointvec_write_happy_single_positive(struct kunit *test)
242{
243 int data = 0;
244 /* Good table. */
245 struct ctl_table table = {
246 .procname = "foo",
247 .data = &data,
248 .maxlen = sizeof(int),
249 .mode = 0644,
250 .proc_handler = proc_dointvec,
251 .extra1 = SYSCTL_ZERO,
252 .extra2 = SYSCTL_ONE_HUNDRED,
253 };
254 char input[] = "9";
255 size_t len = sizeof(input) - 1;
256 loff_t pos = 0;
257 char *buffer = kunit_kzalloc(test, size: len, GFP_USER);
258 char __user *user_buffer = (char __user *)buffer;
259
260 memcpy(buffer, input, len);
261
262 KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_WRITE,
263 user_buffer, &len, &pos));
264 KUNIT_EXPECT_EQ(test, sizeof(input) - 1, len);
265 KUNIT_EXPECT_EQ(test, sizeof(input) - 1, pos);
266 KUNIT_EXPECT_EQ(test, 9, *((int *)table.data));
267}
268
269/*
270 * Same as previous test, but now with negative numbers.
271 */
272static void sysctl_test_dointvec_write_happy_single_negative(struct kunit *test)
273{
274 int data = 0;
275 struct ctl_table table = {
276 .procname = "foo",
277 .data = &data,
278 .maxlen = sizeof(int),
279 .mode = 0644,
280 .proc_handler = proc_dointvec,
281 .extra1 = SYSCTL_ZERO,
282 .extra2 = SYSCTL_ONE_HUNDRED,
283 };
284 char input[] = "-9";
285 size_t len = sizeof(input) - 1;
286 loff_t pos = 0;
287 char *buffer = kunit_kzalloc(test, size: len, GFP_USER);
288 char __user *user_buffer = (char __user *)buffer;
289
290 memcpy(buffer, input, len);
291
292 KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_WRITE,
293 user_buffer, &len, &pos));
294 KUNIT_EXPECT_EQ(test, sizeof(input) - 1, len);
295 KUNIT_EXPECT_EQ(test, sizeof(input) - 1, pos);
296 KUNIT_EXPECT_EQ(test, -9, *((int *)table.data));
297}
298
299/*
300 * Test that writing a value smaller than the minimum possible value is not
301 * allowed.
302 */
303static void sysctl_test_api_dointvec_write_single_less_int_min(
304 struct kunit *test)
305{
306 int data = 0;
307 struct ctl_table table = {
308 .procname = "foo",
309 .data = &data,
310 .maxlen = sizeof(int),
311 .mode = 0644,
312 .proc_handler = proc_dointvec,
313 .extra1 = SYSCTL_ZERO,
314 .extra2 = SYSCTL_ONE_HUNDRED,
315 };
316 size_t max_len = 32, len = max_len;
317 loff_t pos = 0;
318 char *buffer = kunit_kzalloc(test, size: max_len, GFP_USER);
319 char __user *user_buffer = (char __user *)buffer;
320 unsigned long abs_of_less_than_min = (unsigned long)INT_MAX
321 - (INT_MAX + INT_MIN) + 1;
322
323 /*
324 * We use this rigmarole to create a string that contains a value one
325 * less than the minimum accepted value.
326 */
327 KUNIT_ASSERT_LT(test,
328 (size_t)snprintf(buffer, max_len, "-%lu",
329 abs_of_less_than_min),
330 max_len);
331
332 KUNIT_EXPECT_EQ(test, -EINVAL, proc_dointvec(&table, KUNIT_PROC_WRITE,
333 user_buffer, &len, &pos));
334 KUNIT_EXPECT_EQ(test, max_len, len);
335 KUNIT_EXPECT_EQ(test, 0, *((int *)table.data));
336}
337
338/*
339 * Test that writing the maximum possible value works.
340 */
341static void sysctl_test_api_dointvec_write_single_greater_int_max(
342 struct kunit *test)
343{
344 int data = 0;
345 struct ctl_table table = {
346 .procname = "foo",
347 .data = &data,
348 .maxlen = sizeof(int),
349 .mode = 0644,
350 .proc_handler = proc_dointvec,
351 .extra1 = SYSCTL_ZERO,
352 .extra2 = SYSCTL_ONE_HUNDRED,
353 };
354 size_t max_len = 32, len = max_len;
355 loff_t pos = 0;
356 char *buffer = kunit_kzalloc(test, size: max_len, GFP_USER);
357 char __user *user_buffer = (char __user *)buffer;
358 unsigned long greater_than_max = (unsigned long)INT_MAX + 1;
359
360 KUNIT_ASSERT_GT(test, greater_than_max, (unsigned long)INT_MAX);
361 KUNIT_ASSERT_LT(test, (size_t)snprintf(buffer, max_len, "%lu",
362 greater_than_max),
363 max_len);
364 KUNIT_EXPECT_EQ(test, -EINVAL, proc_dointvec(&table, KUNIT_PROC_WRITE,
365 user_buffer, &len, &pos));
366 KUNIT_ASSERT_EQ(test, max_len, len);
367 KUNIT_EXPECT_EQ(test, 0, *((int *)table.data));
368}
369
370static struct kunit_case sysctl_test_cases[] = {
371 KUNIT_CASE(sysctl_test_api_dointvec_null_tbl_data),
372 KUNIT_CASE(sysctl_test_api_dointvec_table_maxlen_unset),
373 KUNIT_CASE(sysctl_test_api_dointvec_table_len_is_zero),
374 KUNIT_CASE(sysctl_test_api_dointvec_table_read_but_position_set),
375 KUNIT_CASE(sysctl_test_dointvec_read_happy_single_positive),
376 KUNIT_CASE(sysctl_test_dointvec_read_happy_single_negative),
377 KUNIT_CASE(sysctl_test_dointvec_write_happy_single_positive),
378 KUNIT_CASE(sysctl_test_dointvec_write_happy_single_negative),
379 KUNIT_CASE(sysctl_test_api_dointvec_write_single_less_int_min),
380 KUNIT_CASE(sysctl_test_api_dointvec_write_single_greater_int_max),
381 {}
382};
383
384static struct kunit_suite sysctl_test_suite = {
385 .name = "sysctl_test",
386 .test_cases = sysctl_test_cases,
387};
388
389kunit_test_suites(&sysctl_test_suite);
390
391MODULE_DESCRIPTION("KUnit test of proc sysctl");
392MODULE_LICENSE("GPL v2");
393

source code of linux/kernel/sysctl-test.c