// https://syzkaller.appspot.com/bug?id=a74718ca902617e6aa7327aa008b25844eccf2d3 // autogenerated by syzkaller (https://github.com/google/syzkaller) #define _GNU_SOURCE #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include unsigned long long procid; static void kill_and_wait(int pid, int* status) { kill(pid, SIGKILL); while (waitpid(-1, status, 0) != pid) { } } static void sleep_ms(uint64_t ms) { usleep(ms * 1000); } static uint64_t current_time_ms(void) { struct timespec ts; if (clock_gettime(CLOCK_MONOTONIC, &ts)) exit(1); return (uint64_t)ts.tv_sec * 1000 + (uint64_t)ts.tv_nsec / 1000000; } static void use_temporary_dir(void) { char tmpdir_template[] = "./syzkaller.XXXXXX"; char* tmpdir = mkdtemp(tmpdir_template); if (!tmpdir) exit(1); if (chmod(tmpdir, 0777)) exit(1); if (chdir(tmpdir)) exit(1); } static void remove_dir(const char* dir) { DIR* dp; struct dirent* ep; dp = opendir(dir); if (dp == NULL) exit(1); while ((ep = readdir(dp))) { if (strcmp(ep->d_name, ".") == 0 || strcmp(ep->d_name, "..") == 0) continue; char filename[FILENAME_MAX]; snprintf(filename, sizeof(filename), "%s/%s", dir, ep->d_name); struct stat st; if (lstat(filename, &st)) exit(1); if (S_ISDIR(st.st_mode)) { remove_dir(filename); continue; } if (unlink(filename)) exit(1); } closedir(dp); if (rmdir(dir)) exit(1); } #define __syscall syscall static void sandbox_common() { if (setsid() == -1) exit(1); struct rlimit rlim; rlim.rlim_cur = rlim.rlim_max = 8 << 20; setrlimit(RLIMIT_MEMLOCK, &rlim); rlim.rlim_cur = rlim.rlim_max = 1 << 20; setrlimit(RLIMIT_FSIZE, &rlim); rlim.rlim_cur = rlim.rlim_max = 1 << 20; setrlimit(RLIMIT_STACK, &rlim); rlim.rlim_cur = rlim.rlim_max = 0; setrlimit(RLIMIT_CORE, &rlim); rlim.rlim_cur = rlim.rlim_max = 256; setrlimit(RLIMIT_NOFILE, &rlim); } static void loop(); static int wait_for_loop(int pid) { if (pid < 0) exit(1); int status = 0; while (waitpid(-1, &status, WUNTRACED) != pid) { } return WEXITSTATUS(status); } static int do_sandbox_setuid(void) { int pid = fork(); if (pid != 0) return wait_for_loop(pid); sandbox_common(); char pwbuf[1024]; struct passwd *pw, pwres; if (getpwnam_r("nobody", &pwres, pwbuf, sizeof(pwbuf), &pw) != 0 || !pw) exit(1); if (setgroups(0, NULL)) exit(1); if (setgid(pw->pw_gid)) exit(1); if (setuid(pw->pw_uid)) exit(1); loop(); exit(1); } static void execute_one(void); #define WAIT_FLAGS 0 static void loop(void) { int iter; for (iter = 0;; iter++) { char cwdbuf[32]; sprintf(cwdbuf, "./%d", iter); if (mkdir(cwdbuf, 0777)) exit(1); int pid = fork(); if (pid < 0) exit(1); if (pid == 0) { if (chdir(cwdbuf)) exit(1); execute_one(); exit(0); } int status = 0; uint64_t start = current_time_ms(); for (;;) { if (waitpid(-1, &status, WNOHANG | WAIT_FLAGS) == pid) break; sleep_ms(1); if (current_time_ms() - start < 5 * 1000) continue; kill_and_wait(pid, &status); break; } remove_dir(cwdbuf); } } void execute_one(void) { memcpy((void*)0x20000480, "./file0\000", 8); syscall(SYS_open, 0x20000480, 0x80000000000206, 0xfffffffffffffffd); memcpy((void*)0x20000000, "./file1\000", 8); syscall(SYS_mkdir, 0x20000000, 4); } int main(void) { syscall(SYS_mmap, 0x20000000, 0x1000000, 3, 0x1012, -1, 0, 0); for (procid = 0; procid < 2; procid++) { if (fork() == 0) { use_temporary_dir(); do_sandbox_setuid(); } } sleep(1000000); return 0; }