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 | |