// https://syzkaller.appspot.com/bug?id=c480e0efb55bb63caae0ced7c35fbdad45d9f715 // 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 #ifndef __NR_bpf #define __NR_bpf 321 #endif 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 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 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 (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); } static void setup_common() { 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); 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 = 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); setup_common(); sandbox_common(); drop_caps(); if (unshare(CLONE_NEWNET)) { } write_file("/proc/sys/net/ipv4/ping_group_range", "0 65535"); sandbox_common_mount_tmpfs(); setup_binderfs(); loop(); exit(1); } static void kill_and_wait(int pid, int* status) { kill(-pid, SIGKILL); kill(pid, SIGKILL); for (int 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() { for (int fd = 3; fd < MAX_FDS; fd++) close(fd); } #define USLEEP_FORKED_CHILD (3 * 50 * 1000) static long handle_clone_ret(long ret) { if (ret != 0) { return ret; } usleep(USLEEP_FORKED_CHILD); syscall(__NR_exit, 0); while (1) { } } static long syz_clone(volatile long flags, volatile long stack, volatile long stack_len, volatile long ptid, volatile long ctid, volatile long tls) { long sp = (stack + stack_len) & ~15; long ret = (long)syscall(__NR_clone, flags & ~CLONE_VM, sp, ptid, ctid, tls); return handle_clone_ret(ret); } static void execute_one(void); #define WAIT_FLAGS __WALL static void loop(void) { int iter = 0; for (;; iter++) { int pid = fork(); if (pid < 0) exit(1); if (pid == 0) { setup_test(); execute_one(); close_fds(); exit(0); } int status = 0; uint64_t start = current_time_ms(); for (;;) { sleep_ms(10); if (waitpid(-1, &status, WNOHANG | WAIT_FLAGS) == pid) break; if (current_time_ms() - start < 5000) continue; kill_and_wait(pid, &status); break; } } } uint64_t r[2] = {0xffffffffffffffff, 0xffffffffffffffff}; void execute_one(void) { intptr_t res = 0; if (write(1, "executing program\n", sizeof("executing program\n") - 1)) { } *(uint32_t*)0x200000c0 = 0x1b; *(uint32_t*)0x200000c4 = 0; *(uint32_t*)0x200000c8 = 0; *(uint32_t*)0x200000cc = 0x8000; *(uint32_t*)0x200000d0 = 0; *(uint32_t*)0x200000d4 = -1; *(uint32_t*)0x200000d8 = 0; memset((void*)0x200000dc, 0, 16); *(uint32_t*)0x200000ec = 0; *(uint32_t*)0x200000f0 = -1; *(uint32_t*)0x200000f4 = 0; *(uint32_t*)0x200000f8 = 0; *(uint32_t*)0x200000fc = 0; *(uint64_t*)0x20000100 = 0; res = syscall(__NR_bpf, /*cmd=*/0ul, /*arg=*/0x200000c0ul, /*size=*/0x48ul); if (res != -1) r[0] = res; *(uint32_t*)0x200000c0 = 0; *(uint32_t*)0x200000c4 = 0xc; *(uint64_t*)0x200000c8 = 0x20000240; memcpy((void*)0x20000240, "\x18\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x18" "\x12\x00\x00", 20); *(uint32_t*)0x20000254 = r[0]; memcpy((void*)0x20000258, "\x00\x00\x00\x00\x00\x00\x00\x00\xb7\x08\x00\x00\x00\x00\x00\x00\x7b" "\x8a\xf8\xff\x00\x00\x00\x00\xbf\xa2\x00\x00\x00\x00\x00\x00\x07\x02" "\x00\x00\xf8\xff\xff\xff\xb7\x03\x00\x00\x00\x00\x00\x00\xb7\x04\x00" "\x00\x02\x09\x00\x00\x85\x00\x00\x00\x43\x00\x00\x00\x95", 65); *(uint64_t*)0x200000d0 = 0; *(uint32_t*)0x200000d8 = 0; *(uint32_t*)0x200000dc = 0; *(uint64_t*)0x200000e0 = 0; *(uint32_t*)0x200000e8 = 0; *(uint32_t*)0x200000ec = 0; memset((void*)0x200000f0, 0, 16); *(uint32_t*)0x20000100 = 0; *(uint32_t*)0x20000104 = 0; *(uint32_t*)0x20000108 = -1; *(uint32_t*)0x2000010c = 0; *(uint64_t*)0x20000110 = 0; *(uint32_t*)0x20000118 = 0; *(uint32_t*)0x2000011c = 0; *(uint64_t*)0x20000120 = 0; *(uint32_t*)0x20000128 = 0; *(uint32_t*)0x2000012c = 0; *(uint32_t*)0x20000130 = 0; *(uint32_t*)0x20000134 = 0; *(uint64_t*)0x20000138 = 0; *(uint64_t*)0x20000140 = 0; *(uint32_t*)0x20000148 = 0; *(uint32_t*)0x2000014c = 0; syscall(__NR_bpf, /*cmd=*/5ul, /*arg=*/0x200000c0ul, /*size=*/0x90ul); *(uint32_t*)0x200000c0 = 0x11; *(uint32_t*)0x200000c4 = 0xc; *(uint64_t*)0x200000c8 = 0x20000240; *(uint64_t*)0x200000d0 = 0x20000200; memcpy((void*)0x20000200, "GPL\000", 4); *(uint32_t*)0x200000d8 = 0; *(uint32_t*)0x200000dc = 0; *(uint64_t*)0x200000e0 = 0; *(uint32_t*)0x200000e8 = 0; *(uint32_t*)0x200000ec = 0; memset((void*)0x200000f0, 0, 16); *(uint32_t*)0x20000100 = 0; *(uint32_t*)0x20000104 = 0; *(uint32_t*)0x20000108 = -1; *(uint32_t*)0x2000010c = 0; *(uint64_t*)0x20000110 = 0; *(uint32_t*)0x20000118 = 0; *(uint32_t*)0x2000011c = 0; *(uint64_t*)0x20000120 = 0; *(uint32_t*)0x20000128 = 0; *(uint32_t*)0x2000012c = 0; *(uint32_t*)0x20000130 = 0; *(uint32_t*)0x20000134 = 0; *(uint64_t*)0x20000138 = 0; *(uint64_t*)0x20000140 = 0; *(uint32_t*)0x20000148 = 0; *(uint32_t*)0x2000014c = 0; res = syscall(__NR_bpf, /*cmd=*/5ul, /*arg=*/0x200000c0ul, /*size=*/0x90ul); if (res != -1) r[1] = res; *(uint64_t*)0x20000340 = 0x200001c0; memcpy((void*)0x200001c0, "mmap_lock_acquire_returned\000", 27); *(uint32_t*)0x20000348 = r[1]; syscall(__NR_bpf, /*cmd=*/0x11ul, /*arg=*/0x20000340ul, /*size=*/0x10ul); syz_clone(/*flags=CLONE_NEWIPC|CLONE_NEWNS*/ 0x8020000, /*stack=*/0, /*stack_len=*/0x500, /*parentid=*/0, /*childtid=*/0, /*tls=*/0); } int main(void) { syscall(__NR_mmap, /*addr=*/0x1ffff000ul, /*len=*/0x1000ul, /*prot=*/0ul, /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul, /*fd=*/-1, /*offset=*/0ul); syscall(__NR_mmap, /*addr=*/0x20000000ul, /*len=*/0x1000000ul, /*prot=PROT_WRITE|PROT_READ|PROT_EXEC*/ 7ul, /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul, /*fd=*/-1, /*offset=*/0ul); syscall(__NR_mmap, /*addr=*/0x21000000ul, /*len=*/0x1000ul, /*prot=*/0ul, /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul, /*fd=*/-1, /*offset=*/0ul); const char* reason; (void)reason; do_sandbox_none(); return 0; }