// https://syzkaller.appspot.com/bug?id=978ae680d1ca9607d2c5ba63b734e3012a122ac4 // 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 #ifndef __NR_bpf #define __NR_bpf 321 #endif static __thread int clone_ongoing; static __thread int skip_segv; static __thread jmp_buf segv_env; static void segv_handler(int sig, siginfo_t* info, void* ctx) { if (__atomic_load_n(&clone_ongoing, __ATOMIC_RELAXED) != 0) { exit(sig); } uintptr_t addr = (uintptr_t)info->si_addr; const uintptr_t prog_start = 1 << 20; const uintptr_t prog_end = 100 << 20; int skip = __atomic_load_n(&skip_segv, __ATOMIC_RELAXED) != 0; int valid = addr < prog_start || addr > prog_end; if (skip && valid) { _longjmp(segv_env, 1); } exit(sig); } static void install_segv_handler(void) { struct sigaction sa; memset(&sa, 0, sizeof(sa)); sa.sa_handler = SIG_IGN; syscall(SYS_rt_sigaction, 0x20, &sa, NULL, 8); syscall(SYS_rt_sigaction, 0x21, &sa, NULL, 8); memset(&sa, 0, sizeof(sa)); sa.sa_sigaction = segv_handler; sa.sa_flags = SA_NODEFER | SA_SIGINFO; sigaction(SIGSEGV, &sa, NULL); sigaction(SIGBUS, &sa, NULL); } #define NONFAILING(...) \ ({ \ int ok = 1; \ __atomic_fetch_add(&skip_segv, 1, __ATOMIC_SEQ_CST); \ if (_setjmp(segv_env) == 0) { \ __VA_ARGS__; \ } else \ ok = 0; \ __atomic_fetch_sub(&skip_segv, 1, __ATOMIC_SEQ_CST); \ ok; \ }) 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_binfmt_misc() { if (mount(0, "/proc/sys/fs/binfmt_misc", "binfmt_misc", 0, 0) && errno != EBUSY) { return NULL; } if (!write_file("/proc/sys/fs/binfmt_misc/register", ":syz0:M:0:\x01::./file0:") || !write_file("/proc/sys/fs/binfmt_misc/register", ":syz1:M:1:\x02::./file0:POC")) return "write(/proc/sys/fs/binfmt_misc/register) failed"; return NULL; } 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"}, {"/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)) { } // bpf$PROG_LOAD arguments: [ // cmd: const = 0x5 (8 bytes) // arg: ptr[in, bpf_prog_t[flags[bpf_prog_type, int32], // bpf_prog_attach_types, bpf_btf_id[opt], fd_bpf_prog[opt]]] { // bpf_prog_t[flags[bpf_prog_type, int32], bpf_prog_attach_types, // bpf_btf_id[opt], fd_bpf_prog[opt]] { // type: bpf_prog_type = 0x11 (4 bytes) // ninsn: bytesize8 = 0xb (4 bytes) // insns: ptr[inout, array[ANYUNION]] { // array[ANYUNION] { // union ANYUNION { // ANYBLOB: buffer: {18 00 00 00 00 00 00 00 00 00 00 00 00 00 00 // 00 18 01 00 00 20 20 70 25 00 00 00 00 00 20 20 20 7b 1a f8 ff // 00 00 00 00 bf a1 00 00 00 00 00 00 07 01 00 00 f8 ff ff ff b7 // 02 00 00 00 00 00 00 b7 03 00 00 00 00 00 00 85 00 00 00 04 00 // 00 00 95} (length 0x51) // } // } // } // license: ptr[in, buffer] { // buffer: {47 50 4c 00} (length 0x4) // } // loglev: int32 = 0x0 (4 bytes) // logsize: len = 0x0 (4 bytes) // log: nil // kern_version: bpf_kern_version = 0x40f00 (4 bytes) // flags: bpf_prog_load_flags = 0x0 (4 bytes) // prog_name: buffer: {00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00} // (length 0x10) prog_ifindex: ifindex (resource) expected_attach_type: // union bpf_prog_attach_types { // fallback: bpf_attach_types = 0x1d (4 bytes) // } // btf_fd: fd_btf (resource) // func_info_rec_size: const = 0x0 (4 bytes) // func_info: nil // func_info_cnt: len = 0x0 (4 bytes) // line_info_rec_size: const = 0x0 (4 bytes) // line_info: nil // line_info_cnt: len = 0x0 (4 bytes) // attach_btf_id: bpf_btf_id (resource) // attach_prog_fd: fd_bpf_prog (resource) // core_relo_cnt: len = 0x0 (4 bytes) // fd_array: nil // core_relos: nil // core_relo_rec_size: const = 0x0 (4 bytes) // log_true_size: int32 = 0x0 (4 bytes) // prog_token_fd: union _bpf_prog_t[flags[bpf_prog_type, int32], // bpf_prog_attach_types, bpf_btf_id[opt], // fd_bpf_prog[opt]]_prog_token_fd_wrapper { // void: buffer: {} (length 0x0) // } // pad: union _bpf_prog_t[flags[bpf_prog_type, int32], // bpf_prog_attach_types, bpf_btf_id[opt], // fd_bpf_prog[opt]]_pad_wrapper { // value: const = 0x0 (4 bytes) // } // } // } // size: len = 0x94 (8 bytes) // ] // returns fd_bpf_prog NONFAILING(*(uint32_t*)0x2000000000c0 = 0x11); NONFAILING(*(uint32_t*)0x2000000000c4 = 0xb); NONFAILING(*(uint64_t*)0x2000000000c8 = 0x200000000180); NONFAILING(memcpy( (void*)0x200000000180, "\x18\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x18\x01" "\x00\x00\x20\x20\x70\x25\x00\x00\x00\x00\x00\x20\x20\x20\x7b\x1a\xf8\xff" "\x00\x00\x00\x00\xbf\xa1\x00\x00\x00\x00\x00\x00\x07\x01\x00\x00\xf8\xff" "\xff\xff\xb7\x02\x00\x00\x00\x00\x00\x00\xb7\x03\x00\x00\x00\x00\x00\x00" "\x85\x00\x00\x00\x04\x00\x00\x00\x95", 81)); NONFAILING(*(uint64_t*)0x2000000000d0 = 0x200000000040); NONFAILING(memcpy((void*)0x200000000040, "GPL\000", 4)); NONFAILING(*(uint32_t*)0x2000000000d8 = 0); NONFAILING(*(uint32_t*)0x2000000000dc = 0); NONFAILING(*(uint64_t*)0x2000000000e0 = 0); NONFAILING(*(uint32_t*)0x2000000000e8 = 0x40f00); NONFAILING(*(uint32_t*)0x2000000000ec = 0); NONFAILING(memset((void*)0x2000000000f0, 0, 16)); NONFAILING(*(uint32_t*)0x200000000100 = 0); NONFAILING(*(uint32_t*)0x200000000104 = 0x1d); NONFAILING(*(uint32_t*)0x200000000108 = -1); NONFAILING(*(uint32_t*)0x20000000010c = 0); NONFAILING(*(uint64_t*)0x200000000110 = 0); NONFAILING(*(uint32_t*)0x200000000118 = 0); NONFAILING(*(uint32_t*)0x20000000011c = 0); NONFAILING(*(uint64_t*)0x200000000120 = 0); NONFAILING(*(uint32_t*)0x200000000128 = 0); NONFAILING(*(uint32_t*)0x20000000012c = 0); NONFAILING(*(uint32_t*)0x200000000130 = 0); NONFAILING(*(uint32_t*)0x200000000134 = 0); NONFAILING(*(uint64_t*)0x200000000138 = 0); NONFAILING(*(uint64_t*)0x200000000140 = 0); NONFAILING(*(uint32_t*)0x200000000148 = 0); NONFAILING(*(uint32_t*)0x20000000014c = 0); NONFAILING(*(uint32_t*)0x200000000150 = 0); res = syscall(__NR_bpf, /*cmd=*/5ul, /*arg=*/0x2000000000c0ul, /*size=*/0x94ul); if (res != -1) r[0] = res; // bpf$BPF_PROG_TEST_RUN arguments: [ // cmd: const = 0xa (8 bytes) // arg: ptr[in, bpf_test_prog_arg] { // bpf_test_prog_arg { // prog: fd_bpf_prog (resource) // retval: const = 0x0 (4 bytes) // insizedata: len = 0x0 (4 bytes) // outsizedata: len = 0x0 (4 bytes) // indata: nil // outdata: nil // repeat: int32 = 0x0 (4 bytes) // dur: const = 0x0 (4 bytes) // insizectx: len = 0x0 (4 bytes) // outsizectx: len = 0x0 (4 bytes) // inctx: nil // outctx: nil // flags: bpf_prog_test_run_flags = 0x7 (4 bytes) // cpu: const = 0x0 (4 bytes) // batch_size: int32 = 0x0 (4 bytes) // pad = 0x0 (4 bytes) // } // } // size: len = 0x50 (8 bytes) // ] NONFAILING(*(uint32_t*)0x200000000380 = r[0]); NONFAILING(*(uint32_t*)0x200000000384 = 0); NONFAILING(*(uint32_t*)0x200000000388 = 0); NONFAILING(*(uint32_t*)0x20000000038c = 0); NONFAILING(*(uint64_t*)0x200000000390 = 0); NONFAILING(*(uint64_t*)0x200000000398 = 0); NONFAILING(*(uint32_t*)0x2000000003a0 = 0); NONFAILING(*(uint32_t*)0x2000000003a4 = 0); NONFAILING(*(uint32_t*)0x2000000003a8 = 0); NONFAILING(*(uint32_t*)0x2000000003ac = 0); NONFAILING(*(uint64_t*)0x2000000003b0 = 0); NONFAILING(*(uint64_t*)0x2000000003b8 = 0); NONFAILING(*(uint32_t*)0x2000000003c0 = 7); NONFAILING(*(uint32_t*)0x2000000003c4 = 0); NONFAILING(*(uint32_t*)0x2000000003c8 = 0); syscall(__NR_bpf, /*cmd=*/0xaul, /*arg=*/0x200000000380ul, /*size=*/0x50ul); } int main(void) { syscall(__NR_mmap, /*addr=*/0x1ffffffff000ul, /*len=*/0x1000ul, /*prot=*/0ul, /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul, /*fd=*/(intptr_t)-1, /*offset=*/0ul); syscall(__NR_mmap, /*addr=*/0x200000000000ul, /*len=*/0x1000000ul, /*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=*/0x1000ul, /*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_binfmt_misc())) printf("the reproducer may not work as expected: binfmt_misc setup failed: " "%s\n", reason); if ((reason = setup_usb())) printf("the reproducer may not work as expected: USB injection setup " "failed: %s\n", reason); install_segv_handler(); do_sandbox_none(); return 0; }