1
2#define _GNU_SOURCE
3
4#include <sys/ptrace.h>
5#include <sys/types.h>
6#include <sys/wait.h>
7#include <sys/syscall.h>
8#include <sys/user.h>
9#include <unistd.h>
10#include <errno.h>
11#include <stddef.h>
12#include <stdio.h>
13#include <err.h>
14#include <string.h>
15#include <asm/ptrace-abi.h>
16#include <sys/auxv.h>
17
18
19#ifdef __x86_64__
20# define user_syscall_nr orig_rax
21# define user_arg0 rdi
22# define user_arg1 rsi
23# define user_arg2 rdx
24# define user_arg3 r10
25# define user_arg4 r8
26# define user_arg5 r9
27# define user_ip rip
28# define user_ax rax
29#else
30# define user_syscall_nr orig_eax
31# define user_arg0 ebx
32# define user_arg1 ecx
33# define user_arg2 edx
34# define user_arg3 esi
35# define user_arg4 edi
36# define user_arg5 ebp
37# define user_ip eip
38# define user_ax eax
39#endif
40
41static int nerrs = 0;
42
43struct syscall_args32 {
44 uint32_t nr, arg0, arg1, arg2, arg3, arg4, arg5;
45};
46
47#ifdef __i386__
48extern void sys32_helper(struct syscall_args32 *, void *);
49extern void int80_and_ret(void);
50#endif
51
52
53
54
55static void do_full_int80(struct syscall_args32 *args)
56{
57#ifdef __x86_64__
58 register unsigned long bp asm("bp") = args->arg5;
59 asm volatile ("int $0x80"
60 : "+a" (args->nr),
61 "+b" (args->arg0), "+c" (args->arg1), "+d" (args->arg2),
62 "+S" (args->arg3), "+D" (args->arg4), "+r" (bp)
63 : : "r8", "r9", "r10", "r11");
64 args->arg5 = bp;
65#else
66 sys32_helper(args, int80_and_ret);
67#endif
68}
69
70#ifdef __i386__
71static void (*vsyscall32)(void);
72
73
74
75
76
77
78static void do_full_vsyscall32(struct syscall_args32 *args)
79{
80 sys32_helper(args, vsyscall32);
81}
82#endif
83
84static siginfo_t wait_trap(pid_t chld)
85{
86 siginfo_t si;
87 if (waitid(P_PID, chld, &si, WEXITED|WSTOPPED) != 0)
88 err(1, "waitid");
89 if (si.si_pid != chld)
90 errx(1, "got unexpected pid in event\n");
91 if (si.si_code != CLD_TRAPPED)
92 errx(1, "got unexpected event type %d\n", si.si_code);
93 return si;
94}
95
96static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
97 int flags)
98{
99 struct sigaction sa;
100 memset(&sa, 0, sizeof(sa));
101 sa.sa_sigaction = handler;
102 sa.sa_flags = SA_SIGINFO | flags;
103 sigemptyset(&sa.sa_mask);
104 if (sigaction(sig, &sa, 0))
105 err(1, "sigaction");
106}
107
108static void setsigign(int sig, int flags)
109{
110 struct sigaction sa;
111 memset(&sa, 0, sizeof(sa));
112 sa.sa_sigaction = (void *)SIG_IGN;
113 sa.sa_flags = flags;
114 sigemptyset(&sa.sa_mask);
115 if (sigaction(sig, &sa, 0))
116 err(1, "sigaction");
117}
118
119static void clearhandler(int sig)
120{
121 struct sigaction sa;
122 memset(&sa, 0, sizeof(sa));
123 sa.sa_handler = SIG_DFL;
124 sigemptyset(&sa.sa_mask);
125 if (sigaction(sig, &sa, 0))
126 err(1, "sigaction");
127}
128
129#ifdef __x86_64__
130# define REG_BP REG_RBP
131#else
132# define REG_BP REG_EBP
133#endif
134
135static void empty_handler(int sig, siginfo_t *si, void *ctx_void)
136{
137}
138
139static void test_sys32_regs(void (*do_syscall)(struct syscall_args32 *))
140{
141 struct syscall_args32 args = {
142 .nr = 224,
143 .arg0 = 10, .arg1 = 11, .arg2 = 12,
144 .arg3 = 13, .arg4 = 14, .arg5 = 15,
145 };
146
147 do_syscall(&args);
148
149 if (args.nr != getpid() ||
150 args.arg0 != 10 || args.arg1 != 11 || args.arg2 != 12 ||
151 args.arg3 != 13 || args.arg4 != 14 || args.arg5 != 15) {
152 printf("[FAIL]\tgetpid() failed to preserve regs\n");
153 nerrs++;
154 } else {
155 printf("[OK]\tgetpid() preserves regs\n");
156 }
157
158 sethandler(SIGUSR1, empty_handler, 0);
159
160 args.nr = 37;
161 args.arg0 = getpid();
162 args.arg1 = SIGUSR1;
163 do_syscall(&args);
164 if (args.nr != 0 ||
165 args.arg0 != getpid() || args.arg1 != SIGUSR1 || args.arg2 != 12 ||
166 args.arg3 != 13 || args.arg4 != 14 || args.arg5 != 15) {
167 printf("[FAIL]\tkill(getpid(), SIGUSR1) failed to preserve regs\n");
168 nerrs++;
169 } else {
170 printf("[OK]\tkill(getpid(), SIGUSR1) preserves regs\n");
171 }
172 clearhandler(SIGUSR1);
173}
174
175static void test_ptrace_syscall_restart(void)
176{
177 printf("[RUN]\tptrace-induced syscall restart\n");
178 pid_t chld = fork();
179 if (chld < 0)
180 err(1, "fork");
181
182 if (chld == 0) {
183 if (ptrace(PTRACE_TRACEME, 0, 0, 0) != 0)
184 err(1, "PTRACE_TRACEME");
185
186 printf("\tChild will make one syscall\n");
187 raise(SIGSTOP);
188
189 syscall(SYS_gettid, 10, 11, 12, 13, 14, 15);
190 _exit(0);
191 }
192
193 int status;
194
195
196 if (waitpid(chld, &status, 0) != chld || !WIFSTOPPED(status))
197 err(1, "waitpid");
198
199 struct user_regs_struct regs;
200
201 printf("[RUN]\tSYSEMU\n");
202 if (ptrace(PTRACE_SYSEMU, chld, 0, 0) != 0)
203 err(1, "PTRACE_SYSEMU");
204 wait_trap(chld);
205
206 if (ptrace(PTRACE_GETREGS, chld, 0, ®s) != 0)
207 err(1, "PTRACE_GETREGS");
208
209 if (regs.user_syscall_nr != SYS_gettid ||
210 regs.user_arg0 != 10 || regs.user_arg1 != 11 ||
211 regs.user_arg2 != 12 || regs.user_arg3 != 13 ||
212 regs.user_arg4 != 14 || regs.user_arg5 != 15) {
213 printf("[FAIL]\tInitial args are wrong (nr=%lu, args=%lu %lu %lu %lu %lu %lu)\n", (unsigned long)regs.user_syscall_nr, (unsigned long)regs.user_arg0, (unsigned long)regs.user_arg1, (unsigned long)regs.user_arg2, (unsigned long)regs.user_arg3, (unsigned long)regs.user_arg4, (unsigned long)regs.user_arg5);
214 nerrs++;
215 } else {
216 printf("[OK]\tInitial nr and args are correct\n");
217 }
218
219 printf("[RUN]\tRestart the syscall (ip = 0x%lx)\n",
220 (unsigned long)regs.user_ip);
221
222
223
224
225
226
227
228 regs.user_ax = regs.user_syscall_nr;
229 regs.user_ip -= 2;
230 if (ptrace(PTRACE_SETREGS, chld, 0, ®s) != 0)
231 err(1, "PTRACE_SETREGS");
232
233 if (ptrace(PTRACE_SYSEMU, chld, 0, 0) != 0)
234 err(1, "PTRACE_SYSEMU");
235 wait_trap(chld);
236
237 if (ptrace(PTRACE_GETREGS, chld, 0, ®s) != 0)
238 err(1, "PTRACE_GETREGS");
239
240 if (regs.user_syscall_nr != SYS_gettid ||
241 regs.user_arg0 != 10 || regs.user_arg1 != 11 ||
242 regs.user_arg2 != 12 || regs.user_arg3 != 13 ||
243 regs.user_arg4 != 14 || regs.user_arg5 != 15) {
244 printf("[FAIL]\tRestart nr or args are wrong (nr=%lu, args=%lu %lu %lu %lu %lu %lu)\n", (unsigned long)regs.user_syscall_nr, (unsigned long)regs.user_arg0, (unsigned long)regs.user_arg1, (unsigned long)regs.user_arg2, (unsigned long)regs.user_arg3, (unsigned long)regs.user_arg4, (unsigned long)regs.user_arg5);
245 nerrs++;
246 } else {
247 printf("[OK]\tRestarted nr and args are correct\n");
248 }
249
250 printf("[RUN]\tChange nr and args and restart the syscall (ip = 0x%lx)\n",
251 (unsigned long)regs.user_ip);
252
253 regs.user_ax = SYS_getpid;
254 regs.user_arg0 = 20;
255 regs.user_arg1 = 21;
256 regs.user_arg2 = 22;
257 regs.user_arg3 = 23;
258 regs.user_arg4 = 24;
259 regs.user_arg5 = 25;
260 regs.user_ip -= 2;
261
262 if (ptrace(PTRACE_SETREGS, chld, 0, ®s) != 0)
263 err(1, "PTRACE_SETREGS");
264
265 if (ptrace(PTRACE_SYSEMU, chld, 0, 0) != 0)
266 err(1, "PTRACE_SYSEMU");
267 wait_trap(chld);
268
269 if (ptrace(PTRACE_GETREGS, chld, 0, ®s) != 0)
270 err(1, "PTRACE_GETREGS");
271
272 if (regs.user_syscall_nr != SYS_getpid ||
273 regs.user_arg0 != 20 || regs.user_arg1 != 21 || regs.user_arg2 != 22 ||
274 regs.user_arg3 != 23 || regs.user_arg4 != 24 || regs.user_arg5 != 25) {
275 printf("[FAIL]\tRestart nr or args are wrong (nr=%lu, args=%lu %lu %lu %lu %lu %lu)\n", (unsigned long)regs.user_syscall_nr, (unsigned long)regs.user_arg0, (unsigned long)regs.user_arg1, (unsigned long)regs.user_arg2, (unsigned long)regs.user_arg3, (unsigned long)regs.user_arg4, (unsigned long)regs.user_arg5);
276 nerrs++;
277 } else {
278 printf("[OK]\tReplacement nr and args are correct\n");
279 }
280
281 if (ptrace(PTRACE_CONT, chld, 0, 0) != 0)
282 err(1, "PTRACE_CONT");
283 if (waitpid(chld, &status, 0) != chld)
284 err(1, "waitpid");
285 if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
286 printf("[FAIL]\tChild failed\n");
287 nerrs++;
288 } else {
289 printf("[OK]\tChild exited cleanly\n");
290 }
291}
292
293static void test_restart_under_ptrace(void)
294{
295 printf("[RUN]\tkernel syscall restart under ptrace\n");
296 pid_t chld = fork();
297 if (chld < 0)
298 err(1, "fork");
299
300 if (chld == 0) {
301 if (ptrace(PTRACE_TRACEME, 0, 0, 0) != 0)
302 err(1, "PTRACE_TRACEME");
303
304 printf("\tChild will take a nap until signaled\n");
305 setsigign(SIGUSR1, SA_RESTART);
306 raise(SIGSTOP);
307
308 syscall(SYS_pause, 0, 0, 0, 0, 0, 0);
309 _exit(0);
310 }
311
312 int status;
313
314
315 if (waitpid(chld, &status, 0) != chld || !WIFSTOPPED(status))
316 err(1, "waitpid");
317
318 struct user_regs_struct regs;
319
320 printf("[RUN]\tSYSCALL\n");
321 if (ptrace(PTRACE_SYSCALL, chld, 0, 0) != 0)
322 err(1, "PTRACE_SYSCALL");
323 wait_trap(chld);
324
325
326
327 if (ptrace(PTRACE_GETREGS, chld, 0, ®s) != 0)
328 err(1, "PTRACE_GETREGS");
329
330 if (regs.user_syscall_nr != SYS_pause ||
331 regs.user_arg0 != 0 || regs.user_arg1 != 0 ||
332 regs.user_arg2 != 0 || regs.user_arg3 != 0 ||
333 regs.user_arg4 != 0 || regs.user_arg5 != 0) {
334 printf("[FAIL]\tInitial args are wrong (nr=%lu, args=%lu %lu %lu %lu %lu %lu)\n", (unsigned long)regs.user_syscall_nr, (unsigned long)regs.user_arg0, (unsigned long)regs.user_arg1, (unsigned long)regs.user_arg2, (unsigned long)regs.user_arg3, (unsigned long)regs.user_arg4, (unsigned long)regs.user_arg5);
335 nerrs++;
336 } else {
337 printf("[OK]\tInitial nr and args are correct\n");
338 }
339
340
341 kill(chld, SIGUSR1);
342
343
344 printf("[RUN]\tSYSCALL\n");
345 if (ptrace(PTRACE_SYSCALL, chld, 0, 0) != 0)
346 err(1, "PTRACE_SYSCALL");
347 wait_trap(chld);
348
349 if (ptrace(PTRACE_GETREGS, chld, 0, ®s) != 0)
350 err(1, "PTRACE_GETREGS");
351
352 if (regs.user_syscall_nr != SYS_pause ||
353 regs.user_arg0 != 0 || regs.user_arg1 != 0 ||
354 regs.user_arg2 != 0 || regs.user_arg3 != 0 ||
355 regs.user_arg4 != 0 || regs.user_arg5 != 0) {
356 printf("[FAIL]\tArgs after SIGUSR1 are wrong (nr=%lu, args=%lu %lu %lu %lu %lu %lu)\n", (unsigned long)regs.user_syscall_nr, (unsigned long)regs.user_arg0, (unsigned long)regs.user_arg1, (unsigned long)regs.user_arg2, (unsigned long)regs.user_arg3, (unsigned long)regs.user_arg4, (unsigned long)regs.user_arg5);
357 nerrs++;
358 } else {
359 printf("[OK]\tArgs after SIGUSR1 are correct (ax = %ld)\n",
360 (long)regs.user_ax);
361 }
362
363
364 if (ptrace(PTRACE_SETREGS, chld, 0, ®s) != 0)
365 err(1, "PTRACE_SETREGS");
366
367
368 if (ptrace(PTRACE_CONT, chld, 0, 0) != 0)
369 err(1, "PTRACE_CONT");
370 if (waitpid(chld, &status, 0) != chld)
371 err(1, "waitpid");
372 if (!WIFSTOPPED(status)) {
373 printf("[FAIL]\tChild was stopped for SIGUSR1 (status = 0x%x)\n", status);
374 nerrs++;
375 } else {
376 printf("[OK]\tChild got SIGUSR1\n");
377 }
378
379
380 printf("[RUN]\tStep again\n");
381 if (ptrace(PTRACE_SYSCALL, chld, 0, 0) != 0)
382 err(1, "PTRACE_SYSCALL");
383 wait_trap(chld);
384
385
386
387 if (ptrace(PTRACE_GETREGS, chld, 0, ®s) != 0)
388 err(1, "PTRACE_GETREGS");
389
390 if (regs.user_syscall_nr != SYS_pause ||
391 regs.user_arg0 != 0 || regs.user_arg1 != 0 ||
392 regs.user_arg2 != 0 || regs.user_arg3 != 0 ||
393 regs.user_arg4 != 0 || regs.user_arg5 != 0) {
394 printf("[FAIL]\tpause did not restart (nr=%lu, args=%lu %lu %lu %lu %lu %lu)\n", (unsigned long)regs.user_syscall_nr, (unsigned long)regs.user_arg0, (unsigned long)regs.user_arg1, (unsigned long)regs.user_arg2, (unsigned long)regs.user_arg3, (unsigned long)regs.user_arg4, (unsigned long)regs.user_arg5);
395 nerrs++;
396 } else {
397 printf("[OK]\tpause(2) restarted correctly\n");
398 }
399
400
401 kill(chld, SIGKILL);
402 if (waitpid(chld, &status, 0) != chld)
403 err(1, "waitpid");
404}
405
406int main()
407{
408 printf("[RUN]\tCheck int80 return regs\n");
409 test_sys32_regs(do_full_int80);
410
411#if defined(__i386__) && (!defined(__GLIBC__) || __GLIBC__ > 2 || __GLIBC_MINOR__ >= 16)
412 vsyscall32 = (void *)getauxval(AT_SYSINFO);
413 printf("[RUN]\tCheck AT_SYSINFO return regs\n");
414 test_sys32_regs(do_full_vsyscall32);
415#endif
416
417 test_ptrace_syscall_restart();
418
419 test_restart_under_ptrace();
420
421 return 0;
422}
423