1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * A ptrace test for testing PTRACE_SYSEMU, PTRACE_SETREGS and
4 * PTRACE_GETREG. This test basically create a child process that executes
5 * syscalls and the parent process check if it is being traced appropriated.
6 *
7 * This test is heavily based on tools/testing/selftests/x86/ptrace_syscall.c
8 * test, and it was adapted to run on Powerpc by
9 * Breno Leitao <leitao@debian.org>
10 */
11 #define _GNU_SOURCE
12
13 #include <sys/ptrace.h>
14 #include <sys/types.h>
15 #include <sys/wait.h>
16 #include <sys/syscall.h>
17 #include <sys/user.h>
18 #include <unistd.h>
19 #include <errno.h>
20 #include <stddef.h>
21 #include <stdio.h>
22 #include <err.h>
23 #include <string.h>
24 #include <sys/auxv.h>
25 #include "utils.h"
26
27 /* Bitness-agnostic defines for user_regs_struct fields. */
28 #define user_syscall_nr gpr[0]
29 #define user_arg0 gpr[3]
30 #define user_arg1 gpr[4]
31 #define user_arg2 gpr[5]
32 #define user_arg3 gpr[6]
33 #define user_arg4 gpr[7]
34 #define user_arg5 gpr[8]
35 #define user_ip nip
36
37 #define PTRACE_SYSEMU 0x1d
38
39 static int nerrs;
40
41 static void wait_trap(pid_t chld)
42 {
43 siginfo_t si;
44
45 if (waitid(P_PID, chld, &si, WEXITED|WSTOPPED) != 0)
46 err(1, "waitid");
47 if (si.si_pid != chld)
48 errx(1, "got unexpected pid in event\n");
49 if (si.si_code != CLD_TRAPPED)
50 errx(1, "got unexpected event type %d\n", si.si_code);
51 }
52
53 static void test_ptrace_syscall_restart(void)
54 {
55 int status;
56 struct pt_regs regs;
57 pid_t chld;
58
59 printf("[RUN]\tptrace-induced syscall restart\n");
60
61 chld = fork();
62 if (chld < 0)
63 err(1, "fork");
64
65 /*
66 * Child process is running 4 syscalls after ptrace.
67 *
68 * 1) getpid()
69 * 2) gettid()
70 * 3) tgkill() -> Send SIGSTOP
71 * 4) gettid() -> Where the tests will happen essentially
72 */
73 if (chld == 0) {
74 if (ptrace(PTRACE_TRACEME, 0, 0, 0) != 0)
75 err(1, "PTRACE_TRACEME");
76
77 pid_t pid = getpid(), tid = syscall(SYS_gettid);
78
79 printf("\tChild will make one syscall\n");
80 syscall(SYS_tgkill, pid, tid, SIGSTOP);
81
82 syscall(SYS_gettid, 10, 11, 12, 13, 14, 15);
83 _exit(0);
84 }
85 /* Parent process below */
86
87 /* Wait for SIGSTOP sent by tgkill above. */
88 if (waitpid(chld, &status, 0) != chld || !WIFSTOPPED(status))
89 err(1, "waitpid");
90
91 printf("[RUN]\tSYSEMU\n");
92 if (ptrace(PTRACE_SYSEMU, chld, 0, 0) != 0)
93 err(1, "PTRACE_SYSEMU");
94 wait_trap(chld);
95
96 if (ptrace(PTRACE_GETREGS, chld, 0, ®s) != 0)
97 err(1, "PTRACE_GETREGS");
98
99 /*
100 * Ptrace trapped prior to executing the syscall, thus r3 still has
101 * the syscall number instead of the sys_gettid() result
102 */
103 if (regs.user_syscall_nr != SYS_gettid ||
104 regs.user_arg0 != 10 || regs.user_arg1 != 11 ||
105 regs.user_arg2 != 12 || regs.user_arg3 != 13 ||
106 regs.user_arg4 != 14 || regs.user_arg5 != 15) {
107 printf("[FAIL]\tInitial args are wrong (nr=%lu, args=%lu %lu %lu %lu %lu %lu)\n",
108 (unsigned long)regs.user_syscall_nr,
109 (unsigned long)regs.user_arg0,
110 (unsigned long)regs.user_arg1,
111 (unsigned long)regs.user_arg2,
112 (unsigned long)regs.user_arg3,
113 (unsigned long)regs.user_arg4,
114 (unsigned long)regs.user_arg5);
115 nerrs++;
116 } else {
117 printf("[OK]\tInitial nr and args are correct\n"); }
118
119 printf("[RUN]\tRestart the syscall (ip = 0x%lx)\n",
120 (unsigned long)regs.user_ip);
121
122 /*
123 * Rewind to retry the same syscall again. This will basically test
124 * the rewind process together with PTRACE_SETREGS and PTRACE_GETREGS.
125 */
126 regs.user_ip -= 4;
127 if (ptrace(PTRACE_SETREGS, chld, 0, ®s) != 0)
128 err(1, "PTRACE_SETREGS");
129
130 if (ptrace(PTRACE_SYSEMU, chld, 0, 0) != 0)
131 err(1, "PTRACE_SYSEMU");
132 wait_trap(chld);
133
134 if (ptrace(PTRACE_GETREGS, chld, 0, ®s) != 0)
135 err(1, "PTRACE_GETREGS");
136
137 if (regs.user_syscall_nr != SYS_gettid ||
138 regs.user_arg0 != 10 || regs.user_arg1 != 11 ||
139 regs.user_arg2 != 12 || regs.user_arg3 != 13 ||
140 regs.user_arg4 != 14 || regs.user_arg5 != 15) {
141 printf("[FAIL]\tRestart nr or args are wrong (nr=%lu, args=%lu %lu %lu %lu %lu %lu)\n",
142 (unsigned long)regs.user_syscall_nr,
143 (unsigned long)regs.user_arg0,
144 (unsigned long)regs.user_arg1,
145 (unsigned long)regs.user_arg2,
146 (unsigned long)regs.user_arg3,
147 (unsigned long)regs.user_arg4,
148 (unsigned long)regs.user_arg5);
149 nerrs++;
150 } else {
151 printf("[OK]\tRestarted nr and args are correct\n");
152 }
153
154 printf("[RUN]\tChange nr and args and restart the syscall (ip = 0x%lx)\n",
155 (unsigned long)regs.user_ip);
156
157 /*
158 * Inject a new syscall (getpid) in the same place the previous
159 * syscall (gettid), rewind and re-execute.
160 */
161 regs.user_syscall_nr = SYS_getpid;
162 regs.user_arg0 = 20;
163 regs.user_arg1 = 21;
164 regs.user_arg2 = 22;
165 regs.user_arg3 = 23;
166 regs.user_arg4 = 24;
167 regs.user_arg5 = 25;
168 regs.user_ip -= 4;
169
170 if (ptrace(PTRACE_SETREGS, chld, 0, ®s) != 0)
171 err(1, "PTRACE_SETREGS");
172
173 if (ptrace(PTRACE_SYSEMU, chld, 0, 0) != 0)
174 err(1, "PTRACE_SYSEMU");
175 wait_trap(chld);
176
177 if (ptrace(PTRACE_GETREGS, chld, 0, ®s) != 0)
178 err(1, "PTRACE_GETREGS");
179
180 /* Check that ptrace stopped at the new syscall that was
181 * injected, and guarantee that it haven't executed, i.e, user_args
182 * contain the arguments and not the syscall return value, for
183 * instance.
184 */
185 if (regs.user_syscall_nr != SYS_getpid
186 || regs.user_arg0 != 20 || regs.user_arg1 != 21
187 || regs.user_arg2 != 22 || regs.user_arg3 != 23
188 || regs.user_arg4 != 24 || regs.user_arg5 != 25) {
189
190 printf("[FAIL]\tRestart nr or args are wrong (nr=%lu, args=%lu %lu %lu %lu %lu %lu)\n",
191 (unsigned long)regs.user_syscall_nr,
192 (unsigned long)regs.user_arg0,
193 (unsigned long)regs.user_arg1,
194 (unsigned long)regs.user_arg2,
195 (unsigned long)regs.user_arg3,
196 (unsigned long)regs.user_arg4,
197 (unsigned long)regs.user_arg5);
198 nerrs++;
199 } else {
200 printf("[OK]\tReplacement nr and args are correct\n");
201 }
202
203 if (ptrace(PTRACE_CONT, chld, 0, 0) != 0)
204 err(1, "PTRACE_CONT");
205
206 if (waitpid(chld, &status, 0) != chld)
207 err(1, "waitpid");
208
209 /* Guarantee that the process executed properly, returning 0 */
210 if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
211 printf("[FAIL]\tChild failed\n");
212 nerrs++;
213 } else {
214 printf("[OK]\tChild exited cleanly\n");
215 }
216 }
217
218 int ptrace_syscall(void)
219 {
220 test_ptrace_syscall_restart();
221
222 return nerrs;
223 }
224
225 int main(void)
226 {
227 return test_harness(ptrace_syscall, "ptrace_syscall");
228 }
229
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