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