// https://syzkaller.appspot.com/bug?id=c92aa0a33fd6b7bd312ad063d4d13d525417cb36 // 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 #include #include #include #include #include #include #include static unsigned long long procid; 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 bool write_file(const char* file, const char* what, ...) { char buf[1024]; va_list args; va_start(args, what); vsnprintf(buf, sizeof(buf), what, args); va_end(args); buf[sizeof(buf) - 1] = 0; int len = strlen(buf); int fd = open(file, O_WRONLY | O_CLOEXEC); if (fd == -1) return false; if (write(fd, buf, len) != len) { int err = errno; close(fd); errno = err; return false; } close(fd); return true; } #define MAX_FDS 30 static void setup_common() { if (mount(0, "/sys/fs/fuse/connections", "fusectl", 0, 0)) { } } static void loop(); static void sandbox_common() { prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0); setpgrp(); setsid(); struct rlimit rlim; rlim.rlim_cur = rlim.rlim_max = (200 << 20); setrlimit(RLIMIT_AS, &rlim); rlim.rlim_cur = rlim.rlim_max = 32 << 20; setrlimit(RLIMIT_MEMLOCK, &rlim); rlim.rlim_cur = rlim.rlim_max = 136 << 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); if (unshare(CLONE_NEWNS)) { } if (unshare(CLONE_NEWIPC)) { } if (unshare(0x02000000)) { } if (unshare(CLONE_NEWUTS)) { } if (unshare(CLONE_SYSVSEM)) { } typedef struct { const char* name; const char* value; } sysctl_t; static const sysctl_t sysctls[] = { {"/proc/sys/kernel/shmmax", "16777216"}, {"/proc/sys/kernel/shmall", "536870912"}, {"/proc/sys/kernel/shmmni", "1024"}, {"/proc/sys/kernel/msgmax", "8192"}, {"/proc/sys/kernel/msgmni", "1024"}, {"/proc/sys/kernel/msgmnb", "1024"}, {"/proc/sys/kernel/sem", "1024 1048576 500 1024"}, }; unsigned i; for (i = 0; i < sizeof(sysctls) / sizeof(sysctls[0]); i++) write_file(sysctls[i].name, sysctls[i].value); } static int wait_for_loop(int pid) { if (pid < 0) exit(1); int status = 0; while (waitpid(-1, &status, __WALL) != pid) { } return WEXITSTATUS(status); } static void drop_caps(void) { struct __user_cap_header_struct cap_hdr = {}; struct __user_cap_data_struct cap_data[2] = {}; cap_hdr.version = _LINUX_CAPABILITY_VERSION_3; cap_hdr.pid = getpid(); if (syscall(SYS_capget, &cap_hdr, &cap_data)) exit(1); const int drop = (1 << CAP_SYS_PTRACE) | (1 << CAP_SYS_NICE); cap_data[0].effective &= ~drop; cap_data[0].permitted &= ~drop; cap_data[0].inheritable &= ~drop; if (syscall(SYS_capset, &cap_hdr, &cap_data)) exit(1); } static int do_sandbox_none(void) { if (unshare(CLONE_NEWPID)) { } int pid = fork(); if (pid != 0) return wait_for_loop(pid); setup_common(); sandbox_common(); drop_caps(); if (unshare(CLONE_NEWNET)) { } loop(); exit(1); } #define FS_IOC_SETFLAGS _IOW('f', 2, long) static void remove_dir(const char* dir) { DIR* dp; struct dirent* ep; int iter = 0; retry: dp = opendir(dir); if (dp == NULL) { if (errno == EMFILE) { exit(1); } 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; } int i; for (i = 0;; i++) { if (unlink(filename) == 0) break; if (errno == EPERM) { int fd = open(filename, O_RDONLY); if (fd != -1) { long flags = 0; if (ioctl(fd, FS_IOC_SETFLAGS, &flags) == 0) { } close(fd); continue; } } if (errno == EROFS) { break; } if (errno != EBUSY || i > 100) exit(1); } } closedir(dp); int i; for (i = 0;; i++) { if (rmdir(dir) == 0) break; if (i < 100) { if (errno == EPERM) { int fd = open(dir, O_RDONLY); if (fd != -1) { long flags = 0; if (ioctl(fd, FS_IOC_SETFLAGS, &flags) == 0) { } close(fd); continue; } } if (errno == EROFS) { break; } if (errno == EBUSY) { continue; } if (errno == ENOTEMPTY) { if (iter < 100) { iter++; goto retry; } } } exit(1); } } static void kill_and_wait(int pid, int* status) { kill(-pid, SIGKILL); kill(pid, SIGKILL); int i; for (i = 0; i < 100; i++) { if (waitpid(-1, status, WNOHANG | __WALL) == pid) return; usleep(1000); } DIR* dir = opendir("/sys/fs/fuse/connections"); if (dir) { for (;;) { struct dirent* ent = readdir(dir); if (!ent) break; if (strcmp(ent->d_name, ".") == 0 || strcmp(ent->d_name, "..") == 0) continue; char abort[300]; snprintf(abort, sizeof(abort), "/sys/fs/fuse/connections/%s/abort", ent->d_name); int fd = open(abort, O_WRONLY); if (fd == -1) { continue; } if (write(fd, abort, 1) < 0) { } close(fd); } closedir(dir); } else { } while (waitpid(-1, status, __WALL) != pid) { } } static void setup_test() { prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0); setpgrp(); write_file("/proc/self/oom_score_adj", "1000"); } static void close_fds() { int fd; for (fd = 3; fd < MAX_FDS; fd++) close(fd); } static void execute_one(void); #define WAIT_FLAGS __WALL 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); setup_test(); execute_one(); close_fds(); 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); } } #ifndef __NR_sched_setattr #define __NR_sched_setattr 314 #endif uint64_t r[1] = {0xffffffffffffffff}; void execute_one(void) { intptr_t res = 0; res = syscall(__NR_socket, 0x2000000000000021ul, 2ul, 2); if (res != -1) r[0] = res; *(uint16_t*)0x20000080 = 0x21; *(uint16_t*)0x20000082 = 0; *(uint16_t*)0x20000084 = 2; *(uint16_t*)0x20000086 = 0x10; *(uint16_t*)0x20000088 = 2; *(uint16_t*)0x2000008a = htobe16(0x4e24); *(uint8_t*)0x2000008c = 0xac; *(uint8_t*)0x2000008d = 0x14; *(uint8_t*)0x2000008e = 0x14; *(uint8_t*)0x2000008f = 0x1e; syscall(__NR_connect, r[0], 0x20000080ul, 0x24ul); *(uint64_t*)0x20005c00 = 0; *(uint32_t*)0x20005c08 = 0; *(uint64_t*)0x20005c10 = 0; *(uint64_t*)0x20005c18 = 0; *(uint64_t*)0x20005c20 = 0x200000c0; memcpy((void*)0x200000c0, "\x18\x00\x00\x00\x00\x00\x00\x00\x10\x01\x00\x00\x01\x00\x00\x00\x77" "\x00\x00\x00\x00\x00\x00\x00\xf4\x1b\x25\xe4\x16\xd5\x89\x37\xe7\xe8" "\x99\xe0\x52\x48\x43\xc9\x57\x7f\x89\xf7\x1e\xbd\xdf\x07\x77\x98\xb4" "\x7a\xb4\x4c\x34\xe1\x6f\x19\xd6\x94\xb9\xc1\x3b\x9e\xe9\xd6\xae\x41" "\xa7\x69\x07\x47\x7a\x20\x91\x22\xad\xca\x7e\x54\x54\xb7\xde\xc9\xd9" "\xa6\x73\x05\xc0\x4a\x8c\xcf\xfc\xa5\x6c\xcb\xca\xbd\xb2\x5c\xc9\x46" "\x28\x34\x8a\x24\x59\x3c\x6f\xbd\xf2\x00\x79\x6a\x8f\xd2\x17\x36\x01" "\x00\x00\x00\x01\x00\x00\x00\x3a\xc4\x3b\x77\x47\x1b\xe9\x14\x70\x7d" "\x2c\x35\x45\xb8\x12\xf7\xf5\x8f\x43\x67\x06\xf1\x7b\x26\xae\x32\x2c" "\x65\xd6\x9e\x51\x52\x8f\x24\x36\x61\x0c\x52\xb7\x24\x99\x31\x41\xa5" "\xcb\x7a\x0a\x9c\x50\xca\x0a\x16\x78\x7a\x4d\x0c\x82\xb7\x25\x6c\x49" "\xaa\xc9\x6b\x00\x00\x00\x04\x21\x50\xa4\x05\x8a\x8e\x43\x47\xe1\x3f" "\x94\xbe\x6d\x87\xfc\x7e\xcd\xaf\x00\x00\x00\x00\x00\x00\x00\x00\x00" "\x00\x00\x92\x4c\x68\x5b\x7a\xe5\xfb\x30\x1c\x55\x2d\x50\xda\x9f\x92" "\xa3\x86\xaf\xac\xda\xca\x3f\xcf\x55\x92\x3c\x1d\xf3\xdf\x70\xb1\xd7" "\xa1\x80\x9d\x4e\x2c\x87\xc2\x24\x0f\x3f\x40\x18\xf5\x4e\x28\x22\xec" "\xf0\xf8\x99\xca\x92\x62\x61\x3e\x28\xc5\x69\xc0\x37\xa4\x6e\x95\x3e" "\x1a\xc7\x3b\xf9\x94\xdb\x37\x10\xac\xa4\xd0\x9b\x98\x37\xf6\x0d\x5e" "\xfe\xc2\x3c\x09\x66\x13\x39\xb3\xc7\x26\xc0\xa0\xc8\xb9\xf4\xfa\x48" "\xe1\xbd\xd0\xfd\xfc\xe8\x24\x4f\xfd\xd9\x54\xac\x75\x00\xf6\xe0\x82" "\x53\x42\x80\x8a\x9f\x21\x2a\x5c\x7c\x4d\xc3\xd8\x68\x0e\x03\x70\x83" "\xb8\xa4\xc1\x2a\x1a\x15\x81\x9d\x52\x66\x95\x2c\xde\x6d\xfa\x68\xb0" "\x6c\x1b\x7f\xd2\xdf\x4c\x86\xa8\x56\xa3\x57\xc2\xef\xd5\xa1\x9e\x5e" "\xef\x58\x42\xbe\xf6\x9e\x3b\x69\xce\xfb\x34\xa1\xdb\xc1\xb3\x9d\x9c" "\xbe\x46\x9e\xbc\x5e\x17\xcd\x33\x65\x8b\x6c\x7b\x91\x78\x6b\xaa\xa8", 425); *(uint64_t*)0x20005c28 = 0x18; *(uint32_t*)0x20005c30 = 0; *(uint32_t*)0x20005c38 = 0; syscall(__NR_sendmmsg, r[0], 0x20005c00ul, 1ul, 0ul); syscall(__NR_sched_setattr, 0, 0ul, 0ul); memcpy((void*)0x20000000, "./file0\000", 8); syscall(__NR_mkdir, 0x20000000ul, 0ul); memcpy((void*)0x20000180, "./file0\000", 8); syscall(__NR_mount, 0x20000000ul, 0x20000180ul, 0ul, 0x2a05809ul, 0ul); memcpy((void*)0x20000380, "./file0\000", 8); memcpy((void*)0x20000340, "./file0\000", 8); syscall(__NR_pivot_root, 0x20000380ul, 0x20000340ul); } int main(void) { syscall(__NR_mmap, 0x20000000ul, 0x1000000ul, 3ul, 0x32ul, -1, 0ul); for (procid = 0; procid < 6; procid++) { if (fork() == 0) { use_temporary_dir(); do_sandbox_none(); } } sleep(1000000); return 0; }