// https://syzkaller.appspot.com/bug?id=cdb658d8cbeff62a4d998e94be26bd578507e32c // 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 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; } static void setup_gadgetfs(); static void setup_binderfs(); static void setup_fusectl(); static void sandbox_common_mount_tmpfs(void) { write_file("/proc/sys/fs/mount-max", "100000"); if (mkdir("./syz-tmp", 0777)) exit(1); if (mount("", "./syz-tmp", "tmpfs", 0, NULL)) exit(1); if (mkdir("./syz-tmp/newroot", 0777)) exit(1); if (mkdir("./syz-tmp/newroot/dev", 0700)) exit(1); unsigned bind_mount_flags = MS_BIND | MS_REC | MS_PRIVATE; if (mount("/dev", "./syz-tmp/newroot/dev", NULL, bind_mount_flags, NULL)) exit(1); if (mkdir("./syz-tmp/newroot/proc", 0700)) exit(1); if (mount("syz-proc", "./syz-tmp/newroot/proc", "proc", 0, NULL)) exit(1); if (mkdir("./syz-tmp/newroot/selinux", 0700)) exit(1); const char* selinux_path = "./syz-tmp/newroot/selinux"; if (mount("/selinux", selinux_path, NULL, bind_mount_flags, NULL)) { if (errno != ENOENT) exit(1); if (mount("/sys/fs/selinux", selinux_path, NULL, bind_mount_flags, NULL) && errno != ENOENT) exit(1); } if (mkdir("./syz-tmp/newroot/sys", 0700)) exit(1); if (mount("/sys", "./syz-tmp/newroot/sys", 0, bind_mount_flags, NULL)) exit(1); if (mount("/sys/kernel/debug", "./syz-tmp/newroot/sys/kernel/debug", NULL, bind_mount_flags, NULL) && errno != ENOENT) exit(1); if (mount("/sys/fs/smackfs", "./syz-tmp/newroot/sys/fs/smackfs", NULL, bind_mount_flags, NULL) && errno != ENOENT) exit(1); if (mount("/proc/sys/fs/binfmt_misc", "./syz-tmp/newroot/proc/sys/fs/binfmt_misc", NULL, bind_mount_flags, NULL) && errno != ENOENT) exit(1); if (mkdir("./syz-tmp/newroot/syz-inputs", 0700)) exit(1); if (mount("/syz-inputs", "./syz-tmp/newroot/syz-inputs", NULL, bind_mount_flags | MS_RDONLY, NULL) && errno != ENOENT) exit(1); if (mkdir("./syz-tmp/pivot", 0777)) exit(1); if (syscall(SYS_pivot_root, "./syz-tmp", "./syz-tmp/pivot")) { if (chdir("./syz-tmp")) exit(1); } else { if (chdir("/")) exit(1); if (umount2("./pivot", MNT_DETACH)) exit(1); } if (chroot("./newroot")) exit(1); if (chdir("/")) exit(1); setup_gadgetfs(); setup_binderfs(); setup_fusectl(); } static void setup_gadgetfs() { if (mkdir("/dev/gadgetfs", 0777)) { } if (mount("gadgetfs", "/dev/gadgetfs", "gadgetfs", 0, NULL)) { } } static void setup_fusectl() { if (mount(0, "/sys/fs/fuse/connections", "fusectl", 0, 0)) { } } static void setup_binderfs() { if (mkdir("/dev/binderfs", 0777)) { } if (mount("binder", "/dev/binderfs", "binder", 0, NULL)) { } if (symlink("/dev/binderfs", "./binderfs")) { } } static void loop(); static void sandbox_common() { prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0); if (getppid() == 1) exit(1); 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 = 128 << 20; setrlimit(RLIMIT_CORE, &rlim); rlim.rlim_cur = rlim.rlim_max = 256; setrlimit(RLIMIT_NOFILE, &rlim); if (unshare(CLONE_NEWNS)) { } if (mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, NULL)) { } 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); sandbox_common(); drop_caps(); if (unshare(CLONE_NEWNET)) { } write_file("/proc/sys/net/ipv4/ping_group_range", "0 65535"); sandbox_common_mount_tmpfs(); loop(); exit(1); } static const char* setup_usb() { if (chmod("/dev/raw-gadget", 0666)) return "failed to chmod /dev/raw-gadget"; return NULL; } static void setup_sysctl() { int cad_pid = fork(); if (cad_pid < 0) exit(1); if (cad_pid == 0) { for (;;) sleep(100); } char tmppid[32]; snprintf(tmppid, sizeof(tmppid), "%d", cad_pid); struct { const char* name; const char* data; } files[] = { {"/sys/kernel/debug/x86/nmi_longest_ns", "10000000000"}, {"/proc/sys/kernel/hung_task_check_interval_secs", "20"}, {"/proc/sys/net/core/bpf_jit_kallsyms", "1"}, {"/proc/sys/net/core/bpf_jit_harden", "0"}, {"/proc/sys/kernel/kptr_restrict", "0"}, {"/proc/sys/kernel/softlockup_all_cpu_backtrace", "1"}, {"/proc/sys/fs/mount-max", "100"}, {"/proc/sys/vm/oom_dump_tasks", "0"}, {"/proc/sys/debug/exception-trace", "0"}, {"/proc/sys/kernel/printk", "7 4 1 3"}, {"/proc/sys/kernel/keys/gc_delay", "1"}, {"/proc/sys/vm/oom_kill_allocating_task", "1"}, {"/sys/kernel/debug/failslab/task-filter", "Y"}, {"/sys/kernel/debug/fail_page_alloc/task-filter", "Y"}, {"/sys/kernel/debug/fail_futex/task-filter", "Y"}, {"/sys/kernel/debug/fail_usercopy/task-filter", "Y"}, {"/sys/kernel/debug/fail_make_request/task-filter", "Y"}, {"/sys/kernel/debug/fail_io_timeout/task-filter", "Y"}, {"/sys/kernel/debug/fail_iommufd/task-filter", "Y"}, {"/proc/sys/kernel/ctrl-alt-del", "0"}, {"/proc/sys/kernel/cad_pid", tmppid}, }; for (size_t i = 0; i < sizeof(files) / sizeof(files[0]); i++) { if (!write_file(files[i].name, files[i].data)) { } } kill(cad_pid, SIGKILL); while (waitpid(cad_pid, NULL, 0) != cad_pid) ; } uint64_t r[1] = {0xffffffffffffffff}; void loop(void) { intptr_t res = 0; if (write(1, "executing program\n", sizeof("executing program\n") - 1)) { } // getsockopt$TIPC_DEST_DROPPABLE arguments: [ // fd: sock_tipc (resource) // level: const = 0x10f (4 bytes) // opt: const = 0x81 (4 bytes) // val: ptr[out, int32] { // int32 = 0x0 (4 bytes) // } // len: ptr[inout, bytesize] { // bytesize = 0x4 (4 bytes) // } // ] *(uint32_t*)0x2000000000c0 = 4; syscall(__NR_getsockopt, /*fd=*/(intptr_t)-1, /*level=*/0x10f, /*opt=*/0x81, /*val=*/0x200000000080ul, /*len=*/0x2000000000c0ul); // add_key$user arguments: [ // type: ptr[in, buffer] { // buffer: {75 73 65 72 00} (length 0x5) // } // desc: ptr[in, key_desc] { // key_desc { // prefix: buffer: {73 79 7a} (length 0x3) // id: proc = 0xffffffffffffffff (1 bytes) // z: const = 0x0 (1 bytes) // } // } // payload: ptr[in, buffer] { // buffer: {} (length 0x0) // } // paylen: len = 0xc9 (8 bytes) // keyring: keyring (resource) // ] // returns user_key memcpy((void*)0x2000000003c0, "user\000", 5); memcpy((void*)0x200000000440, "syz", 3); *(uint8_t*)0x200000000443 = 0; *(uint8_t*)0x200000000444 = 0; syscall(__NR_add_key, /*type=*/0x2000000003c0ul, /*desc=*/0x200000000440ul, /*payload=*/0x2000000000c0ul, /*paylen=*/0xc9ul, /*keyring=*/0xfffffffd); // mkdirat arguments: [ // fd: fd_dir (resource) // path: ptr[in, buffer] { // buffer: {2e 2f 6d 6e 74 00} (length 0x6) // } // mode: open_mode = 0x1ff (8 bytes) // ] memcpy((void*)0x200000000440, "./mnt\000", 6); syscall( __NR_mkdirat, /*fd=*/0xffffff9c, /*path=*/0x200000000440ul, /*mode=S_IXOTH|S_IWOTH|S_IROTH|S_IXGRP|S_IWGRP|S_IRGRP|S_IXUSR|S_IWUSR|0x100*/ 0x1fful); // mount arguments: [ // src: ptr[in, blockdev_filename] { // union blockdev_filename { // filename: buffer: {00} (length 0x1) // } // } // dst: ptr[in, buffer] { // buffer: {2e 2f 6d 6e 74 00} (length 0x6) // } // type: ptr[in, buffer] { // buffer: {65 63 72 79 70 74 66 73 00} (length 0x9) // } // flags: mount_flags = 0x0 (8 bytes) // data: ptr[in, buffer] { // buffer: {65 63 72 79 70 74 66 73 5f 73 69 67 3d 73 79 7a 2c 65 63 72 // 79 70 74 66 73 5f 66 6e 65 6b 5f 73 69 67 3d 73 79 7a 2c 65 63 72 79 // 70 74 66 73 5f 63 69 70 68 65 72 3d 61 65 73 2c 65 63 72 79 70 74 66 // 73 5f 6b 65 79 5f 62 79 74 65 73 3d 31 36 00} (length 0x51) // } // ] memset((void*)0x200000000400, 0, 1); memcpy((void*)0x200000000000, "./mnt\000", 6); memcpy((void*)0x200000000480, "ecryptfs\000", 9); memcpy((void*)0x200000000500, "ecryptfs_sig=syz,ecryptfs_fnek_sig=syz,ecryptfs_cipher=aes,ecryptfs_" "key_bytes=16\000", 81); syscall(__NR_mount, /*src=*/0x200000000400ul, /*dst=*/0x200000000000ul, /*type=*/0x200000000480ul, /*flags=*/0ul, /*data=*/0x200000000500ul); // open$dir arguments: [ // file: ptr[in, buffer] { // buffer: {2e 2f 6d 6e 74 00} (length 0x6) // } // flags: open_flags = 0x18000 (8 bytes) // mode: open_mode = 0x9 (8 bytes) // ] // returns fd_dir memcpy((void*)0x200000000040, "./mnt\000", 6); res = syscall(__NR_open, /*file=*/0x200000000040ul, /*flags=O_LARGEFILE|O_DIRECTORY*/ 0x18000ul, /*mode=S_IXOTH|S_IXGRP*/ 9ul); if (res != -1) r[0] = res; // mkdirat arguments: [ // fd: fd_dir (resource) // path: ptr[in, buffer] { // buffer: {2e 2f 6d 6e 74 00} (length 0x6) // } // mode: open_mode = 0x2 (8 bytes) // ] memcpy((void*)0x200000000100, "./mnt\000", 6); syscall(__NR_mkdirat, /*fd=*/r[0], /*path=*/0x200000000100ul, /*mode=S_IWOTH*/ 2ul); } int main(void) { syscall(__NR_mmap, /*addr=*/0x1ffffffff000ul, /*len=*/0x1000, /*prot=*/0ul, /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul, /*fd=*/(intptr_t)-1, /*offset=*/0ul); syscall(__NR_mmap, /*addr=*/0x200000000000ul, /*len=*/0x1000000, /*prot=PROT_WRITE|PROT_READ|PROT_EXEC*/ 7ul, /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul, /*fd=*/(intptr_t)-1, /*offset=*/0ul); syscall(__NR_mmap, /*addr=*/0x200001000000ul, /*len=*/0x1000, /*prot=*/0ul, /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul, /*fd=*/(intptr_t)-1, /*offset=*/0ul); setup_sysctl(); const char* reason; (void)reason; if ((reason = setup_usb())) printf("the reproducer may not work as expected: USB injection setup " "failed: %s\n", reason); do_sandbox_none(); return 0; }