// https://syzkaller.appspot.com/bug?id=6bd6841f2932e940f20f0e15e3a6937f3068a2c6 // 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 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 { char buf[1024]; char* hash; strncpy(buf, (char*)a0, sizeof(buf) - 1); buf[sizeof(buf) - 1] = 0; while ((hash = strchr(buf, '#'))) { *hash = '0' + (char)(a1 % 10); a1 /= 10; } return open(buf, a2, 0); } } 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 = 0; 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[8] = {0xffffffffffffffff, 0xffffffffffffffff, 0xffffffffffffffff, 0x0, 0x0, 0x0, 0xffffffffffffffff, 0x0}; void loop(void) { intptr_t res = 0; memcpy((void*)0x20000000, "/proc/self/exe\000", 15); res = syscall(__NR_openat, 0xffffff9c, 0x20000000ul, 0ul, 0ul); if (res != -1) r[0] = res; syscall(__NR_close, r[0]); memcpy((void*)0x20000000, "/proc/self/exe\000", 15); res = syscall(__NR_openat, 0xffffff9c, 0x20000000ul, 0ul, 0ul); if (res != -1) r[1] = res; memcpy((void*)0x200002c0, "/dev/dri/card#\000", 15); res = -1; res = syz_open_dev(0x200002c0, 0, 0); if (res != -1) r[2] = res; *(uint32_t*)0x20000040 = 0x80; *(uint32_t*)0x20000044 = 0xc26d; *(uint32_t*)0x20000048 = 0x7e; *(uint32_t*)0x2000004c = 0; res = syscall(__NR_ioctl, r[2], 0xc02064b2, 0x20000040ul); if (res != -1) r[3] = *(uint32_t*)0x20000050; syscall(__NR_close, r[1]); *(uint32_t*)0x20000100 = r[3]; syscall(__NR_ioctl, r[2], 0xc00c642d, 0x20000100ul); *(uint32_t*)0x20000084 = 0; *(uint32_t*)0x20000088 = r[1]; res = syscall(__NR_ioctl, r[2], 0xc00c642e, 0x20000080ul); if (res != -1) r[4] = *(uint32_t*)0x20000080; *(uint32_t*)0x200000c0 = r[4]; res = syscall(__NR_ioctl, r[2], 0xc008640a, 0x200000c0ul); if (res != -1) r[5] = *(uint32_t*)0x200000c4; *(uint32_t*)0x20000140 = r[5]; syscall(__NR_ioctl, r[2], 0xc0106441, 0x20000140ul); memcpy((void*)0x200002c0, "/dev/dri/card#\000", 15); res = -1; res = syz_open_dev(0x200002c0, 0, 0); if (res != -1) r[6] = res; *(uint32_t*)0x20000040 = 0x80; *(uint32_t*)0x20000044 = 0xc26d; *(uint32_t*)0x20000048 = 0x7e; *(uint32_t*)0x2000004c = 0; res = syscall(__NR_ioctl, r[6], 0xc02064b2, 0x20000040ul); if (res != -1) r[7] = *(uint32_t*)0x20000050; *(uint32_t*)0x20000080 = r[7]; syscall(__NR_ioctl, r[2], 0xc00464b4, 0x20000080ul); *(uint32_t*)0x20000740 = r[0]; *(uint16_t*)0x20000744 = 0x2015; *(uint16_t*)0x20000746 = 0; syscall(__NR_ppoll, 0x20000740ul, 1ul, 0ul, 0ul, 0ul); 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; }