// https://syzkaller.appspot.com/bug?id=37556d70764e226e660023fad17c9c0316cb6f1d // 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_memfd_create #define __NR_memfd_create 319 #endif static unsigned long long procid; 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 struct fs_image_segment { void* data; uintptr_t size; uintptr_t offset; }; static int setup_loop_device(long unsigned size, long unsigned nsegs, struct fs_image_segment* segs, const char* loopname, int* memfd_p, int* loopfd_p) { int err = 0, loopfd = -1; int memfd = syscall(__NR_memfd_create, "syzkaller", 0); if (memfd == -1) { err = errno; goto error; } if (ftruncate(memfd, size)) { err = errno; goto error_close_memfd; } for (size_t i = 0; i < nsegs; i++) { if (pwrite(memfd, segs[i].data, segs[i].size, segs[i].offset) < 0) { } } loopfd = open(loopname, O_RDWR); if (loopfd == -1) { err = errno; goto error_close_memfd; } if (ioctl(loopfd, LOOP_SET_FD, memfd)) { if (errno != EBUSY) { err = errno; goto error_close_loop; } ioctl(loopfd, LOOP_CLR_FD, 0); usleep(1000); if (ioctl(loopfd, LOOP_SET_FD, memfd)) { err = errno; goto error_close_loop; } } *memfd_p = memfd; *loopfd_p = loopfd; return 0; error_close_loop: close(loopfd); error_close_memfd: close(memfd); error: errno = err; return -1; } static long syz_mount_image(volatile long fsarg, volatile long dir, volatile unsigned long size, volatile unsigned long nsegs, volatile long segments, volatile long flags, volatile long optsarg, volatile long change_dir) { struct fs_image_segment* segs = (struct fs_image_segment*)segments; int res = -1, err = 0, loopfd = -1, memfd = -1, need_loop_device = !!segs; char* mount_opts = (char*)optsarg; char* target = (char*)dir; char* fs = (char*)fsarg; char* source = NULL; char loopname[64]; if (need_loop_device) { memset(loopname, 0, sizeof(loopname)); snprintf(loopname, sizeof(loopname), "/dev/loop%llu", procid); if (setup_loop_device(size, nsegs, segs, loopname, &memfd, &loopfd) == -1) return -1; source = loopname; } mkdir(target, 0777); char opts[256]; memset(opts, 0, sizeof(opts)); if (strlen(mount_opts) > (sizeof(opts) - 32)) { } strncpy(opts, mount_opts, sizeof(opts) - 32); if (strcmp(fs, "iso9660") == 0) { flags |= MS_RDONLY; } else if (strncmp(fs, "ext", 3) == 0) { if (strstr(opts, "errors=panic") || strstr(opts, "errors=remount-ro") == 0) strcat(opts, ",errors=continue"); } else if (strcmp(fs, "xfs") == 0) { strcat(opts, ",nouuid"); } res = mount(source, target, fs, flags, opts); if (res == -1) { err = errno; goto error_clear_loop; } res = open(target, O_RDONLY | O_DIRECTORY); if (res == -1) { err = errno; goto error_clear_loop; } if (change_dir) { res = chdir(target); if (res == -1) { err = errno; } } error_clear_loop: if (need_loop_device) { ioctl(loopfd, LOOP_CLR_FD, 0); close(loopfd); close(memfd); } errno = err; return res; } 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"); setup_binderfs(); loop(); exit(1); } static void close_fds() { for (int fd = 3; fd < MAX_FDS; fd++) close(fd); } uint64_t r[2] = {0xffffffffffffffff, 0xffffffffffffffff}; void loop(void) { intptr_t res = 0; memcpy((void*)0x200000c0, "vfat\000", 5); memcpy((void*)0x20000080, "./file0\000", 8); *(uint64_t*)0x20000140 = 0x20000000; memcpy((void*)0x20000000, "\xeb\x3c\x90\x6d\x8d\x66\x73\xfd\xd2\x61\x74\x00\x02\x80\x01\x00\x02" "\x40\x00\x00\x04\xf8\x01", 23); *(uint64_t*)0x20000148 = 0x17; *(uint64_t*)0x20000150 = 0; *(uint64_t*)0x20000158 = 0x20000400; memcpy( (void*)0x20000400, "\x57\x59\x5a\x4b\x41\x4c\x4c\x45\x52\x20\x20\x08\x5a\xc1\x9f\x69\xf2\xb2" "\xb1\xea\x1b\x8a\x0a\xc9\x13\x5e\xed\x1d\xf1\xd1\x00\x1c\xc2\xde\x85\x0f" "\x06\x00\x00\x00\x00\x00\x00\x00\xf7\xe7\x5e\xff\xac\x2a\xc4\xc1\x5e\x29" "\xfb\x3c\x18\xfa\xff\xf8\xd1\x98\xe3\x12\x47\x5f\xfa\x1d\x00\x00\x00\x00" "\x00\x00\xad\x25\x82\x2a\x17\xb1\x7f\x46\x3e\x10\x41\x79\xc1\x9c\x2a\xd2" "\xfb\xdd\xc0\x77\x7d\xf2\xec\x4f\x62\x82\x60\x86\x70\x4d\xc5\x75\xb6\x97" "\x06\xd1\x15\x47\x81\x27\xd9\xf0\xbe\x59\xcd\xc0\x76\x84\x48\x0b\xe4\xb8" "\x86\x93\x7d\x8f\xb4\xf0\xff\x94\xe3\xa7\x6e\xcb\xc6\x3c\x2a\xe0\xb3\x87" "\xef\x96\xd2\x06\x6a\x83\x2e\xb0\x74\x3d\x5b\x8d\x2d\xd7\x53\x1c\x1b\x63" "\xa8\xb2\x81\xdd\xaa\x3d\x1a\x5a\xb2\xe1\xe3\xed\x7a\xba\x34\x0e\xad\x25" "\x71\x05\xf3\x6c\xf4\x99\x31\x92\x41\x1d\x5a\xbb\x4c\x65\xf2\xe6\xc2\xb2" "\x8b\x69\xb9\x68\x1b\x56\xdb\xb1\x9b\x01\x1d\x41\xf6\x17\x3b\x1e\x9d\xe0" "\xae\x2d\x37\xcc\x0d\x67\x74\x57\xb0\x61\x22\x0e\x7a\xa9\x70\x46\x35\x16" "\xf0\x82\x4f\x1d\xf4\xdd\x9b\xbf\x16\x5f\xa3\xb0\xea\x49\xdc\xa4\x04\x73" "\x07\x74\x59\xda\xe8\xce\x5e\x07\x33\x2c\xa1\x1f\x60\xaa\x39\x88\x64\xd5" "\x2c\x56\x96\x0c\x7d\x5c\x65\xcf\x9f\xe7\xdf\x48\x48\x7d\xf8\x6c\x42\x22" "\xae\x62\x1f\x0c\x1e\xc0\xbc\x3c\xf7\x94\x3f\xa8\x31\x5d\x96\x31\x40\x0b" "\x5c\x16\x57\xd4\xfd\x72\x91\xfe\xbd\xc1\xf9\xe0\x04\x65\xfa\xac\x75\xf3" "\xd1\x60\x46\xef\x88\x84\xbe\xc8\x06\x7e\x1d\xe4\xd0\x6e\xcd\x94\x44\xd6" "\x3d\x34\x8e\xb2\x20\x9f\xbe\xbc\x00\xc1\xcf\x2a\x4a\x09\x6e\x52\xde\xe0" "\xdd\xd6\x81\xa9\xf8\xb9\x12\x55\xa8\xa5\xd4\xaf\xd8\x97\xa2\x39\xf4\xae" "\x53\x95\x97\x3e\xd6\x93\xfa\x0a\xcf\x68\x79\x7f\x73\xd1\xd5\xb7\x26\x90" "\xe6\x05\x63\xd9\x0d\x8b\x58\xde\x72\xaf\x8d\x1f\x7b\x7e\x9e\xe0\xa9\x39" "\xd1\x01\x8d\x95\xf0\xe4\x01\x37\x4c\x40\x10\x08\xa7\x0e\x5a\x4b\x32\x42" "\x3c\x70\xd2\xc6\x99\xeb\xdd\x13\x95\xf4\x00\x00\x00\x00\x00\x00\x00" "\x00", 450); *(uint64_t*)0x20000160 = 0x1c2; *(uint64_t*)0x20000168 = 0x5fe; memcpy( (void*)0x200001c0, "\x69\x6f\x63\x68\x61\x72\x73\x65\x74\x3d\x63\x70\x38\x35\x32\x2c\x6e\x6f" "\x6e\x75\x6d\x74\x61\x69\x6c\x3d\x30\x2c\x73\x68\x6f\x72\x74\x6e\x61\x6d" "\x65\x3d\x6d\x69\x78\x65\x64\x2c\x73\x68\x6f\x72\x74\x6e\x61\x6d\x65\x3d" "\x6c\x6f\x77\x65\x72\x2c\x63\x68\x65\x63\x6b\x3d\x73\x74\x72\x69\x63\x74" "\x2c\x73\x68\x6f\x72\x74\x6e\x61\x6d\x65\x3d\x77\x69\x6e\x39\x35\x2c\x64" "\x69\x73\x63\x61\x72\x64\x2c\x69\x6f\x63\x68\x61\x72\x73\x65\x74\x3d\x6b" "\x6f\x69\x38\x2d\x72\x2c\x69\x6f\x63\x68\x61\x72\x73\x65\x74\x3d\x63\x70" "\x38\x36\x35\x2c\x75\x6e\x69\x5f\x78\x6c\x61\x74\x65\x3d\x31\x2c\x75\x73" "\x65\x66\x72\x65\x65\x2c\x63\x6f\x64\x65\x70\x61\x67\x65\x3d\x39\x35\x30" "\x2c\x72\x6f\x64\x69\x72\x2c\x66\x6c\x75\x73\x68\x2c\x73\x68\x6f\x72\x74" "\x6e\x61\x6d\x65\x3d\x77\x69\x6e\x6e\x74\x2c\x00\xbe\x40\x08\xf1\x70\x1f" "\x99\x0e\x33\x4c\x5c\x4f\xb7\x1d\x09\xff\x36\x79\xa3\x00\x97\xd1\x9a\xc8" "\xfc\x38\xaa\x26\x70\xf4\xd8\x28\x94\x8f\xb6\x09\x3f\x51\x92\x97\xc6\xfa" "\x0a\x5e\xe5\x46\x9a\xba\xb4\x09\x99\xd5\x52\xb7\x3c\x57\x9a\xcd\xc3\xa5" "\xe8\x81\x99\x5a\x96\xd6\x7f\x91\x43\x25\xb5\x0e\x82\x4b\x16\x3c\x60\x7c" "\xf5\xd0\x4d\x02\xaa\x00\xb3\xf9\x0c\xa4\x46\x6f\xcb\xee\xa5\x05\xea\x92" "\xe5\xa9\xa3\xb4\xc8\x46\x81\xc5\x1e\x0d", 298); syz_mount_image(0x200000c0, 0x20000080, 0x8000, 2, 0x20000140, 0x2010000, 0x200001c0, 0); memcpy((void*)0x20000140, "./file0\000", 8); syscall(__NR_chdir, 0x20000140ul); memcpy((void*)0x20000000, "./file0\000", 8); res = syscall(__NR_openat, 0xffffff9c, 0x20000000ul, 0x34caa03f8d9ceef2ul, 0ul); if (res != -1) r[0] = res; memcpy((void*)0x200003c0, "./file0\000", 8); syscall(__NR_unlink, 0x200003c0ul); memcpy((void*)0x200000c0, "cgroup.controllers\000", 19); res = syscall(__NR_openat, 0xffffff9c, 0x200000c0ul, 0x275aul, 0ul); if (res != -1) r[1] = res; syscall(__NR_write, r[1], 0x20000140ul, 0x3af4701eul); *(uint64_t*)0x20000580 = 0x200016c0; memset((void*)0x200016c0, 74, 1); *(uint64_t*)0x20000588 = 1; syscall(__NR_pwritev, r[0], 0x20000580ul, 1ul, 0, 0); close_fds(); } int main(void) { syscall(__NR_mmap, 0x1ffff000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul); syscall(__NR_mmap, 0x20000000ul, 0x1000000ul, 7ul, 0x32ul, -1, 0ul); syscall(__NR_mmap, 0x21000000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul); do_sandbox_none(); return 0; }