// https://syzkaller.appspot.com/bug?id=3c1f47967b7cbd399d3ba3e65f297a29aa1c5f92 // autogenerated by syzkaller (http://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 __attribute__((noreturn)) static void doexit(int status) { volatile unsigned i; syscall(__NR_exit_group, status); for (i = 0;; i++) { } } #include #include #include #include #include #include #include const int kFailStatus = 67; const int kRetryStatus = 69; static void fail(const char* msg, ...) { int e = errno; va_list args; va_start(args, msg); vfprintf(stderr, msg, args); va_end(args); fprintf(stderr, " (errno %d)\n", e); doexit((e == ENOMEM || e == EAGAIN) ? kRetryStatus : kFailStatus); } static void use_temporary_dir() { char tmpdir_template[] = "./syzkaller.XXXXXX"; char* tmpdir = mkdtemp(tmpdir_template); if (!tmpdir) fail("failed to mkdtemp"); if (chmod(tmpdir, 0777)) fail("failed to chmod"); if (chdir(tmpdir)) fail("failed to chdir"); } static uintptr_t syz_open_dev(uintptr_t a0, uintptr_t a1, uintptr_t a2) { if (a0 == 0xc || a0 == 0xb) { char buf[128]; sprintf(buf, "/dev/%s/%d:%d", a0 == 0xc ? "char" : "block", (uint8_t)a1, (uint8_t)a2); return open(buf, O_RDWR, 0); } else { char buf[1024]; char* hash; strncpy(buf, (char*)a0, sizeof(buf)); buf[sizeof(buf) - 1] = 0; while ((hash = strchr(buf, '#'))) { *hash = '0' + (char)(a1 % 10); a1 /= 10; } return open(buf, a2, 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 = 128 << 20; setrlimit(RLIMIT_AS, &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); #define CLONE_NEWCGROUP 0x02000000 unshare(CLONE_NEWNS); unshare(CLONE_NEWIPC); unshare(CLONE_NEWCGROUP); unshare(CLONE_NEWNET); unshare(CLONE_NEWUTS); unshare(CLONE_SYSVSEM); } 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) { close(fd); return false; } close(fd); return true; } static int real_uid; static int real_gid; __attribute__((aligned(64 << 10))) static char sandbox_stack[1 << 20]; static int namespace_sandbox_proc(void* arg) { sandbox_common(); write_file("/proc/self/setgroups", "deny"); if (!write_file("/proc/self/uid_map", "0 %d 1\n", real_uid)) fail("write of /proc/self/uid_map failed"); if (!write_file("/proc/self/gid_map", "0 %d 1\n", real_gid)) fail("write of /proc/self/gid_map failed"); if (mkdir("./syz-tmp", 0777)) fail("mkdir(syz-tmp) failed"); if (mount("", "./syz-tmp", "tmpfs", 0, NULL)) fail("mount(tmpfs) failed"); if (mkdir("./syz-tmp/newroot", 0777)) fail("mkdir failed"); if (mkdir("./syz-tmp/newroot/dev", 0700)) fail("mkdir failed"); if (mount("/dev", "./syz-tmp/newroot/dev", NULL, MS_BIND | MS_REC | MS_PRIVATE, NULL)) fail("mount(dev) failed"); if (mkdir("./syz-tmp/newroot/proc", 0700)) fail("mkdir failed"); if (mount(NULL, "./syz-tmp/newroot/proc", "proc", 0, NULL)) fail("mount(proc) failed"); if (mkdir("./syz-tmp/pivot", 0777)) fail("mkdir failed"); if (syscall(SYS_pivot_root, "./syz-tmp", "./syz-tmp/pivot")) { if (chdir("./syz-tmp")) fail("chdir failed"); } else { if (chdir("/")) fail("chdir failed"); if (umount2("./pivot", MNT_DETACH)) fail("umount failed"); } if (chroot("./newroot")) fail("chroot failed"); if (chdir("/")) fail("chdir failed"); 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)) fail("capget failed"); cap_data[0].effective &= ~(1 << CAP_SYS_PTRACE); cap_data[0].permitted &= ~(1 << CAP_SYS_PTRACE); cap_data[0].inheritable &= ~(1 << CAP_SYS_PTRACE); if (syscall(SYS_capset, &cap_hdr, &cap_data)) fail("capset failed"); loop(); doexit(1); } static int do_sandbox_namespace(int executor_pid, bool enable_tun) { int pid; real_uid = getuid(); real_gid = getgid(); mprotect(sandbox_stack, 4096, PROT_NONE); pid = clone(namespace_sandbox_proc, &sandbox_stack[sizeof(sandbox_stack) - 64], CLONE_NEWUSER | CLONE_NEWPID, NULL); if (pid < 0) fail("sandbox clone failed"); return pid; } static void test(); void loop() { while (1) { test(); } } long r[1]; uint64_t procid; void test() { memset(r, -1, sizeof(r)); syscall(__NR_mmap, 0x20000000, 0xfff000, 3, 0x32, -1, 0); memcpy((void*)0x20000000, "/dev/sg#", 9); r[0] = syz_open_dev(0x20000000, 0, 2); *(uint64_t*)0x20001000 = 0; *(uint64_t*)0x20001008 = 6; *(uint16_t*)0x20001010 = 0; *(uint16_t*)0x20001012 = 0; *(uint32_t*)0x20001014 = 0; *(uint64_t*)0x20001018 = 0; *(uint64_t*)0x20001020 = 0; *(uint16_t*)0x20001028 = 0; *(uint16_t*)0x2000102a = 0; *(uint32_t*)0x2000102c = 7; *(uint64_t*)0x20001030 = 0; *(uint64_t*)0x20001038 = 0x2710; *(uint16_t*)0x20001040 = 0; *(uint16_t*)0x20001042 = 0; *(uint32_t*)0x20001044 = 0; *(uint64_t*)0x20001048 = 0; *(uint64_t*)0x20001050 = 0; *(uint16_t*)0x20001058 = 0; *(uint16_t*)0x2000105a = 0; *(uint32_t*)0x2000105c = 0; syscall(__NR_write, r[0], 0x20001000, 0x60); *(uint64_t*)0x20977000 = 0x20e4afea; *(uint64_t*)0x20977008 = 0x16; *(uint64_t*)0x20977010 = 0x20603000; *(uint64_t*)0x20977018 = 0xfa; *(uint64_t*)0x20977020 = 0x2075afb6; *(uint64_t*)0x20977028 = 0x4a; *(uint64_t*)0x20977030 = 0x206b9000; *(uint64_t*)0x20977038 = 0x3d; *(uint64_t*)0x20977040 = 0x2077cfbe; *(uint64_t*)0x20977048 = 0x42; *(uint64_t*)0x20977050 = 0x20c87fbc; *(uint64_t*)0x20977058 = 0x44; *(uint64_t*)0x20977060 = 0x20291f01; *(uint64_t*)0x20977068 = 0xff; syscall(__NR_readv, r[0], 0x20977000, 7); } int main() { char* cwd = get_current_dir_name(); for (procid = 0; procid < 8; procid++) { if (fork() == 0) { for (;;) { if (chdir(cwd)) fail("failed to chdir"); use_temporary_dir(); int pid = do_sandbox_namespace(procid, false); int status = 0; while (waitpid(pid, &status, __WALL) != pid) { } } } } sleep(1000000); return 0; }