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8#define _GNU_SOURCE
9#include <sys/prctl.h>
10#include <sys/sysinfo.h>
11#include <sys/syscall.h>
12#include <signal.h>
13
14#include <asm/unistd.h>
15#include "../kselftest_harness.h"
16
17#ifndef PR_SET_SYSCALL_USER_DISPATCH
18# define PR_SET_SYSCALL_USER_DISPATCH 59
19# define PR_SYS_DISPATCH_OFF 0
20# define PR_SYS_DISPATCH_ON 1
21# define SYSCALL_DISPATCH_FILTER_ALLOW 0
22# define SYSCALL_DISPATCH_FILTER_BLOCK 1
23#endif
24
25#ifndef SYS_USER_DISPATCH
26# define SYS_USER_DISPATCH 2
27#endif
28
29#ifdef __NR_syscalls
30# define MAGIC_SYSCALL_1 (__NR_syscalls + 1)
31#else
32# define MAGIC_SYSCALL_1 (0xff00)
33#endif
34
35#define SYSCALL_DISPATCH_ON(x) ((x) = SYSCALL_DISPATCH_FILTER_BLOCK)
36#define SYSCALL_DISPATCH_OFF(x) ((x) = SYSCALL_DISPATCH_FILTER_ALLOW)
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59TEST_SIGNAL(dispatch_trigger_sigsys, SIGSYS)
60{
61 char sel = SYSCALL_DISPATCH_FILTER_ALLOW;
62 struct sysinfo info;
63 int ret;
64
65 ret = sysinfo(&info);
66 ASSERT_EQ(0, ret);
67
68 ret = prctl(PR_SET_SYSCALL_USER_DISPATCH, PR_SYS_DISPATCH_ON, 0, 0, &sel);
69 ASSERT_EQ(0, ret) {
70 TH_LOG("Kernel does not support CONFIG_SYSCALL_USER_DISPATCH");
71 }
72
73 SYSCALL_DISPATCH_ON(sel);
74
75 sysinfo(&info);
76
77 EXPECT_FALSE(true) {
78 TH_LOG("Unreachable!");
79 }
80}
81
82TEST(bad_prctl_param)
83{
84 char sel = SYSCALL_DISPATCH_FILTER_ALLOW;
85 int op;
86
87
88 op = -1;
89 prctl(PR_SET_SYSCALL_USER_DISPATCH, op, 0, 0, &sel);
90 ASSERT_EQ(EINVAL, errno);
91
92
93 op = PR_SYS_DISPATCH_OFF;
94
95
96 prctl(PR_SET_SYSCALL_USER_DISPATCH, op, 0x1, 0x0, 0);
97 EXPECT_EQ(EINVAL, errno);
98
99
100 prctl(PR_SET_SYSCALL_USER_DISPATCH, op, 0x0, 0xff, 0);
101 EXPECT_EQ(EINVAL, errno);
102
103
104 prctl(PR_SET_SYSCALL_USER_DISPATCH, op, 0x0, 0x0, &sel);
105 EXPECT_EQ(EINVAL, errno);
106
107
108 errno = 0;
109 prctl(PR_SET_SYSCALL_USER_DISPATCH, op, 0x0, 0x0, 0x0);
110 EXPECT_EQ(0, errno);
111
112
113 op = PR_SYS_DISPATCH_ON;
114
115
116 prctl(PR_SET_SYSCALL_USER_DISPATCH, op, 0x1, 0x0, &sel);
117 EXPECT_EQ(EINVAL, errno);
118 prctl(PR_SET_SYSCALL_USER_DISPATCH, op, -1L, 0x0, &sel);
119 EXPECT_EQ(EINVAL, errno);
120
121
122 prctl(PR_SET_SYSCALL_USER_DISPATCH, op, 0x0, 0x1, (void *) -1);
123 ASSERT_EQ(EFAULT, errno);
124
125
126
127
128 prctl(PR_SET_SYSCALL_USER_DISPATCH, PR_SYS_DISPATCH_ON, 1, -1L, &sel);
129 ASSERT_EQ(EINVAL, errno) {
130 TH_LOG("Should reject bad syscall range");
131 }
132
133
134
135
136 prctl(PR_SET_SYSCALL_USER_DISPATCH, PR_SYS_DISPATCH_ON, -1L, 0x1, &sel);
137 ASSERT_EQ(EINVAL, errno) {
138 TH_LOG("Should reject bad syscall range");
139 }
140}
141
142
143
144
145
146char glob_sel;
147int nr_syscalls_emulated;
148int si_code;
149int si_errno;
150
151static void handle_sigsys(int sig, siginfo_t *info, void *ucontext)
152{
153 si_code = info->si_code;
154 si_errno = info->si_errno;
155
156 if (info->si_syscall == MAGIC_SYSCALL_1)
157 nr_syscalls_emulated++;
158
159
160 SYSCALL_DISPATCH_OFF(glob_sel);
161}
162
163TEST(dispatch_and_return)
164{
165 long ret;
166 struct sigaction act;
167 sigset_t mask;
168
169 glob_sel = 0;
170 nr_syscalls_emulated = 0;
171 si_code = 0;
172 si_errno = 0;
173
174 memset(&act, 0, sizeof(act));
175 sigemptyset(&mask);
176
177 act.sa_sigaction = handle_sigsys;
178 act.sa_flags = SA_SIGINFO;
179 act.sa_mask = mask;
180
181 ret = sigaction(SIGSYS, &act, NULL);
182 ASSERT_EQ(0, ret);
183
184
185 SYSCALL_DISPATCH_OFF(glob_sel);
186
187 ret = prctl(PR_SET_SYSCALL_USER_DISPATCH, PR_SYS_DISPATCH_ON, 0, 0, &glob_sel);
188 ASSERT_EQ(0, ret) {
189 TH_LOG("Kernel does not support CONFIG_SYSCALL_USER_DISPATCH");
190 }
191
192
193 SYSCALL_DISPATCH_OFF(glob_sel);
194 ret = syscall(MAGIC_SYSCALL_1);
195 EXPECT_EQ(-1, ret) {
196 TH_LOG("Dispatch triggered unexpectedly");
197 }
198
199
200 nr_syscalls_emulated = 0;
201 SYSCALL_DISPATCH_ON(glob_sel);
202
203 ret = syscall(MAGIC_SYSCALL_1);
204 EXPECT_EQ(MAGIC_SYSCALL_1, ret) {
205 TH_LOG("Failed to intercept syscall");
206 }
207 EXPECT_EQ(1, nr_syscalls_emulated) {
208 TH_LOG("Failed to emulate syscall");
209 }
210 ASSERT_EQ(SYS_USER_DISPATCH, si_code) {
211 TH_LOG("Bad si_code in SIGSYS");
212 }
213 ASSERT_EQ(0, si_errno) {
214 TH_LOG("Bad si_errno in SIGSYS");
215 }
216}
217
218TEST_SIGNAL(bad_selector, SIGSYS)
219{
220 long ret;
221 struct sigaction act;
222 sigset_t mask;
223 struct sysinfo info;
224
225 glob_sel = SYSCALL_DISPATCH_FILTER_ALLOW;
226 nr_syscalls_emulated = 0;
227 si_code = 0;
228 si_errno = 0;
229
230 memset(&act, 0, sizeof(act));
231 sigemptyset(&mask);
232
233 act.sa_sigaction = handle_sigsys;
234 act.sa_flags = SA_SIGINFO;
235 act.sa_mask = mask;
236
237 ret = sigaction(SIGSYS, &act, NULL);
238 ASSERT_EQ(0, ret);
239
240
241 SYSCALL_DISPATCH_OFF(glob_sel);
242
243 ret = prctl(PR_SET_SYSCALL_USER_DISPATCH, PR_SYS_DISPATCH_ON, 0, 0, &glob_sel);
244 ASSERT_EQ(0, ret) {
245 TH_LOG("Kernel does not support CONFIG_SYSCALL_USER_DISPATCH");
246 }
247
248 glob_sel = -1;
249
250 sysinfo(&info);
251
252
253
254
255
256 EXPECT_FALSE(true) {
257 TH_LOG("Unreachable!");
258 }
259}
260
261TEST(disable_dispatch)
262{
263 int ret;
264 struct sysinfo info;
265 char sel = 0;
266
267 ret = prctl(PR_SET_SYSCALL_USER_DISPATCH, PR_SYS_DISPATCH_ON, 0, 0, &sel);
268 ASSERT_EQ(0, ret) {
269 TH_LOG("Kernel does not support CONFIG_SYSCALL_USER_DISPATCH");
270 }
271
272
273 SYSCALL_DISPATCH_OFF(glob_sel);
274
275 ret = prctl(PR_SET_SYSCALL_USER_DISPATCH, PR_SYS_DISPATCH_OFF, 0, 0, 0);
276 EXPECT_EQ(0, ret) {
277 TH_LOG("Failed to unset syscall user dispatch");
278 }
279
280
281 SYSCALL_DISPATCH_ON(glob_sel);
282
283 ret = syscall(__NR_sysinfo, &info);
284 EXPECT_EQ(0, ret) {
285 TH_LOG("Dispatch triggered unexpectedly");
286 }
287}
288
289TEST(direct_dispatch_range)
290{
291 int ret = 0;
292 struct sysinfo info;
293 char sel = SYSCALL_DISPATCH_FILTER_ALLOW;
294
295
296
297
298
299 ret = prctl(PR_SET_SYSCALL_USER_DISPATCH, PR_SYS_DISPATCH_ON, 0, -1L, &sel);
300 ASSERT_EQ(0, ret) {
301 TH_LOG("Kernel does not support CONFIG_SYSCALL_USER_DISPATCH");
302 }
303
304 SYSCALL_DISPATCH_ON(sel);
305
306 ret = sysinfo(&info);
307 ASSERT_EQ(0, ret) {
308 TH_LOG("Dispatch triggered unexpectedly");
309 }
310}
311
312TEST_HARNESS_MAIN
313