1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * Author: Alexey Gladkov <gladkov.alexey@gmail.com> |
4 | */ |
5 | #define _GNU_SOURCE |
6 | #include <sys/types.h> |
7 | #include <sys/wait.h> |
8 | #include <sys/time.h> |
9 | #include <sys/resource.h> |
10 | #include <sys/prctl.h> |
11 | #include <sys/stat.h> |
12 | |
13 | #include <unistd.h> |
14 | #include <stdlib.h> |
15 | #include <stdio.h> |
16 | #include <string.h> |
17 | #include <sched.h> |
18 | #include <signal.h> |
19 | #include <limits.h> |
20 | #include <fcntl.h> |
21 | #include <errno.h> |
22 | #include <err.h> |
23 | |
24 | #define NR_CHILDS 2 |
25 | |
26 | static char *service_prog; |
27 | static uid_t user = 60000; |
28 | static uid_t group = 60000; |
29 | |
30 | static void setrlimit_nproc(rlim_t n) |
31 | { |
32 | pid_t pid = getpid(); |
33 | struct rlimit limit = { |
34 | .rlim_cur = n, |
35 | .rlim_max = n |
36 | }; |
37 | |
38 | warnx("(pid=%d): Setting RLIMIT_NPROC=%ld" , pid, n); |
39 | |
40 | if (setrlimit(RLIMIT_NPROC, &limit) < 0) |
41 | err(EXIT_FAILURE, "(pid=%d): setrlimit(RLIMIT_NPROC)" , pid); |
42 | } |
43 | |
44 | static pid_t fork_child(void) |
45 | { |
46 | pid_t pid = fork(); |
47 | |
48 | if (pid < 0) |
49 | err(EXIT_FAILURE, "fork" ); |
50 | |
51 | if (pid > 0) |
52 | return pid; |
53 | |
54 | pid = getpid(); |
55 | |
56 | warnx("(pid=%d): New process starting ..." , pid); |
57 | |
58 | if (prctl(PR_SET_PDEATHSIG, SIGKILL) < 0) |
59 | err(EXIT_FAILURE, "(pid=%d): prctl(PR_SET_PDEATHSIG)" , pid); |
60 | |
61 | signal(SIGUSR1, SIG_DFL); |
62 | |
63 | warnx("(pid=%d): Changing to uid=%d, gid=%d" , pid, user, group); |
64 | |
65 | if (setgid(group) < 0) |
66 | err(EXIT_FAILURE, "(pid=%d): setgid(%d)" , pid, group); |
67 | if (setuid(user) < 0) |
68 | err(EXIT_FAILURE, "(pid=%d): setuid(%d)" , pid, user); |
69 | |
70 | warnx("(pid=%d): Service running ..." , pid); |
71 | |
72 | warnx("(pid=%d): Unshare user namespace" , pid); |
73 | if (unshare(CLONE_NEWUSER) < 0) |
74 | err(EXIT_FAILURE, "unshare(CLONE_NEWUSER)" ); |
75 | |
76 | char *const argv[] = { "service" , NULL }; |
77 | char *const envp[] = { "I_AM_SERVICE=1" , NULL }; |
78 | |
79 | warnx("(pid=%d): Executing real service ..." , pid); |
80 | |
81 | execve(service_prog, argv, envp); |
82 | err(EXIT_FAILURE, "(pid=%d): execve" , pid); |
83 | } |
84 | |
85 | int main(int argc, char **argv) |
86 | { |
87 | size_t i; |
88 | pid_t child[NR_CHILDS]; |
89 | int wstatus[NR_CHILDS]; |
90 | int childs = NR_CHILDS; |
91 | pid_t pid; |
92 | |
93 | if (getenv("I_AM_SERVICE" )) { |
94 | pause(); |
95 | exit(EXIT_SUCCESS); |
96 | } |
97 | |
98 | service_prog = argv[0]; |
99 | pid = getpid(); |
100 | |
101 | warnx("(pid=%d) Starting testcase" , pid); |
102 | |
103 | /* |
104 | * This rlimit is not a problem for root because it can be exceeded. |
105 | */ |
106 | setrlimit_nproc(1); |
107 | |
108 | for (i = 0; i < NR_CHILDS; i++) { |
109 | child[i] = fork_child(); |
110 | wstatus[i] = 0; |
111 | usleep(250000); |
112 | } |
113 | |
114 | while (1) { |
115 | for (i = 0; i < NR_CHILDS; i++) { |
116 | if (child[i] <= 0) |
117 | continue; |
118 | |
119 | errno = 0; |
120 | pid_t ret = waitpid(child[i], &wstatus[i], WNOHANG); |
121 | |
122 | if (!ret || (!WIFEXITED(wstatus[i]) && !WIFSIGNALED(wstatus[i]))) |
123 | continue; |
124 | |
125 | if (ret < 0 && errno != ECHILD) |
126 | warn("(pid=%d): waitpid(%d)" , pid, child[i]); |
127 | |
128 | child[i] *= -1; |
129 | childs -= 1; |
130 | } |
131 | |
132 | if (!childs) |
133 | break; |
134 | |
135 | usleep(250000); |
136 | |
137 | for (i = 0; i < NR_CHILDS; i++) { |
138 | if (child[i] <= 0) |
139 | continue; |
140 | kill(child[i], SIGUSR1); |
141 | } |
142 | } |
143 | |
144 | for (i = 0; i < NR_CHILDS; i++) { |
145 | if (WIFEXITED(wstatus[i])) |
146 | warnx("(pid=%d): pid %d exited, status=%d" , |
147 | pid, -child[i], WEXITSTATUS(wstatus[i])); |
148 | else if (WIFSIGNALED(wstatus[i])) |
149 | warnx("(pid=%d): pid %d killed by signal %d" , |
150 | pid, -child[i], WTERMSIG(wstatus[i])); |
151 | |
152 | if (WIFSIGNALED(wstatus[i]) && WTERMSIG(wstatus[i]) == SIGUSR1) |
153 | continue; |
154 | |
155 | warnx("(pid=%d): Test failed" , pid); |
156 | exit(EXIT_FAILURE); |
157 | } |
158 | |
159 | warnx("(pid=%d): Test passed" , pid); |
160 | exit(EXIT_SUCCESS); |
161 | } |
162 | |