// https://syzkaller.appspot.com/bug?id=4cbec535ee5ffaa9bd224540911a33edd354220a // 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_seccomp #define __NR_seccomp 317 #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 long syz_open_dev(volatile long a0, volatile long a1, volatile long 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 { unsigned long nb = a1; char buf[1024]; char* hash; strncpy(buf, (char*)a0, sizeof(buf) - 1); buf[sizeof(buf) - 1] = 0; while ((hash = strchr(buf, '#'))) { *hash = '0' + (char)(nb % 10); nb /= 10; } return open(buf, a2, 0); } } 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 int inject_fault(int nth) { int fd; fd = open("/proc/thread-self/fail-nth", O_RDWR); if (fd == -1) exit(1); char buf[16]; sprintf(buf, "%d", nth); if (write(fd, buf, strlen(buf)) != (ssize_t)strlen(buf)) exit(1); return fd; } 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); } static const char* setup_fault() { int fd = open("/proc/self/make-it-fail", O_WRONLY); if (fd == -1) return "CONFIG_FAULT_INJECTION is not enabled"; close(fd); fd = open("/proc/thread-self/fail-nth", O_WRONLY); if (fd == -1) return "kernel does not have systematic fault injection support"; close(fd); static struct { const char* file; const char* val; bool fatal; } files[] = { {"/sys/kernel/debug/failslab/ignore-gfp-wait", "N", true}, {"/sys/kernel/debug/fail_futex/ignore-private", "N", false}, {"/sys/kernel/debug/fail_page_alloc/ignore-gfp-highmem", "N", false}, {"/sys/kernel/debug/fail_page_alloc/ignore-gfp-wait", "N", false}, {"/sys/kernel/debug/fail_page_alloc/min-order", "0", false}, }; unsigned i; for (i = 0; i < sizeof(files) / sizeof(files[0]); i++) { if (!write_file(files[i].file, files[i].val)) { if (files[i].fatal) return "failed to write fault injection file"; } } return NULL; } 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 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[4] = {0xffffffffffffffff, 0xffffffffffffffff, 0xffffffffffffffff, 0xffffffffffffffff}; void execute_one(void) { intptr_t res = 0; if (write(1, "executing program\n", sizeof("executing program\n") - 1)) { } // seccomp$SECCOMP_SET_MODE_FILTER_LISTENER arguments: [ // op: const = 0x1 (8 bytes) // flags: seccomp_flags_listener = 0x0 (8 bytes) // arg: ptr[in, sock_fprog] { // sock_fprog { // len: len = 0x1 (2 bytes) // pad = 0x0 (6 bytes) // filter: ptr[in, array[sock_filter]] { // array[sock_filter] { // sock_filter { // code: int16 = 0x6 (2 bytes) // jt: int8 = 0x0 (1 bytes) // jf: int8 = 0x0 (1 bytes) // k: int32 = 0x7fff0006 (4 bytes) // } // } // } // } // } // ] // returns fd_seccomp *(uint16_t*)0x2000000000c0 = 1; *(uint64_t*)0x2000000000c8 = 0x200000000000; *(uint16_t*)0x200000000000 = 6; *(uint8_t*)0x200000000002 = 0; *(uint8_t*)0x200000000003 = 0; *(uint32_t*)0x200000000004 = 0x7fff0006; res = syscall(__NR_seccomp, /*op=*/1ul, /*flags=*/0ul, /*arg=*/0x2000000000c0ul); if (res != -1) r[0] = res; // openat$dma_heap arguments: [ // fd: const = 0xffffffffffffff9c (8 bytes) // file: ptr[in, buffer] { // buffer: {2f 64 65 76 2f 64 6d 61 5f 68 65 61 70 2f 73 79 73 74 65 6d // 00} (length 0x15) // } // flags: open_flags = 0x0 (4 bytes) // mode: const = 0x0 (2 bytes) // ] // returns fd_dma_heap memcpy((void*)0x200000000000, "/dev/dma_heap/system\000", 21); res = syscall(__NR_openat, /*fd=*/0xffffffffffffff9cul, /*file=*/0x200000000000ul, /*flags=*/0, /*mode=*/0); if (res != -1) r[1] = res; // ioctl$DMA_HEAP_IOCTL_ALLOC arguments: [ // fd: fd_dma_heap (resource) // cmd: const = 0xc0184800 (4 bytes) // arg: ptr[inout, dma_heap_allocation_data] { // dma_heap_allocation_data { // len: int64 = 0x1020004 (8 bytes) // fd: fd (resource) // fd_flags: dma_open_flags = 0x80000 (4 bytes) // heap_flags: const = 0x0 (8 bytes) // } // } // ] *(uint64_t*)0x200000000100 = 0x1020004; *(uint32_t*)0x200000000108 = r[0]; *(uint32_t*)0x20000000010c = 0x80000; *(uint64_t*)0x200000000110 = 0; res = syscall(__NR_ioctl, /*fd=*/r[1], /*cmd=*/0xc0184800, /*arg=*/0x200000000100ul); if (res != -1) r[2] = *(uint32_t*)0x200000000108; // syz_open_dev$dri arguments: [ // dev: ptr[in, buffer] { // buffer: {2f 64 65 76 2f 64 72 69 2f 63 61 72 64 23 00} (length 0xf) // } // id: intptr = 0x48 (8 bytes) // flags: open_flags = 0x80000 (8 bytes) // ] // returns fd_dri memcpy((void*)0x200000000180, "/dev/dri/card#\000", 15); res = -1; res = syz_open_dev(/*dev=*/0x200000000180, /*id=*/0x48, /*flags=O_CLOEXEC*/ 0x80000); if (res != -1) r[3] = res; // ioctl$DRM_IOCTL_PRIME_FD_TO_HANDLE arguments: [ // fd: fd_dri (resource) // cmd: const = 0xc00c642e (4 bytes) // arg: ptr[inout, drm_prime_handle$DRM_IOCTL_PRIME_FD_TO_HANDLE] { // drm_prime_handle$DRM_IOCTL_PRIME_FD_TO_HANDLE { // handle: drm_gem_handle (resource) // flags: const = 0x0 (4 bytes) // fd: fd_dri (resource) // } // } // ] *(uint32_t*)0x2000000000c4 = 0; *(uint32_t*)0x2000000000c8 = r[2]; inject_fault(10); syscall(__NR_ioctl, /*fd=*/r[3], /*cmd=*/0xc00c642e, /*arg=*/0x2000000000c0ul); } 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); 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_fault())) printf("the reproducer may not work as expected: fault injection setup " "failed: %s\n", 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; }