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e4aebf06 AG |
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 | } |