// https://syzkaller.appspot.com/bug?id=cdf8792e8c8aff2dfc22bc6103530cc9d7cb4d77 // 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; } static void setup_common() { if (mount(0, "/sys/fs/fuse/connections", "fusectl", 0, 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 = (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 (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); } 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)) { } loop(); exit(1); } uint64_t r[4] = {0xffffffffffffffff, 0xffffffffffffffff, 0xffffffffffffffff, 0xffffffffffffffff}; void loop(void) { intptr_t res = 0; res = syscall(__NR_socket, 0x10ul, 3ul, 0ul); if (res != -1) r[0] = res; res = syscall(__NR_socket, 0x10ul, 3ul, 0ul); if (res != -1) r[1] = res; res = syscall(__NR_socket, 0x10ul, 0x803ul, 0); if (res != -1) r[2] = res; *(uint64_t*)0x200001c0 = 0; *(uint32_t*)0x200001c8 = 0; *(uint64_t*)0x200001d0 = 0x20000180; *(uint64_t*)0x20000180 = 0; *(uint64_t*)0x20000188 = 0; *(uint64_t*)0x200001d8 = 1; *(uint64_t*)0x200001e0 = 0; *(uint64_t*)0x200001e8 = 0; *(uint32_t*)0x200001f0 = 0; syscall(__NR_sendmsg, r[2], 0x200001c0ul, 0ul); *(uint32_t*)0x20000200 = 0x14; res = syscall(__NR_getsockname, r[2], 0x20000100ul, 0x20000200ul); if (res != -1) r[3] = *(uint32_t*)0x20000104; *(uint64_t*)0x20000240 = 0; *(uint32_t*)0x20000248 = 0; *(uint64_t*)0x20000250 = 0x20000140; *(uint64_t*)0x20000140 = 0x200003c0; memcpy((void*)0x200003c0, "\x38\x00\x00\x00\x24\x00\x07\x05\x00\x00\x00\x00" "\x00\xa2\xa3\x00\x05\x00\x00\x00", 20); *(uint32_t*)0x200003d4 = r[3]; memcpy((void*)0x200003d8, "\x00\x00\x00\x00\xff\xff\xff\xff\x00\x00\x00\x00" "\x09\x00\x01\x00\x68\x66\x73\x63\x00\x00\x00\x00" "\x08\x00\x02\x00\x00\x00\x00\x00", 32); *(uint64_t*)0x20000148 = 0x38; *(uint64_t*)0x20000258 = 1; *(uint64_t*)0x20000260 = 0; *(uint64_t*)0x20000268 = 0; *(uint32_t*)0x20000270 = 0; syscall(__NR_sendmsg, r[1], 0x20000240ul, 0ul); *(uint64_t*)0x200001c0 = 0; *(uint32_t*)0x200001c8 = 0; *(uint64_t*)0x200001d0 = 0x20000180; *(uint64_t*)0x20000180 = 0x20000400; memcpy( (void*)0x20000400, "4\000\000\000,\000\'\r\000\000\000\000\000\000\000\000\000\000\000\000", 20); *(uint32_t*)0x20000414 = r[3]; memcpy((void*)0x20000418, "\x00\x00\x00\x03\x00\x00\x00\x00\x0f\x00\x00\x00\x0a\x00\x01\x00\xcb" "\xb4\x17\x9b\x85\x9c\xc7\x04\x73\x16\x66\x9e\x4e\x20\xb3\x54\x72\x6f" "\x75\x74\x65\x00\x00\x00\x04\x00\x02\x00\x5d\x29\x33\xd7\xfa\x2b\x59" "\x0e\xc2\x39\x37\x1a\x36\x2d\xf1\x3d\x18\x36\x0c\xe7\xfe\x84\xc2\x8f" "\x38\xd1\x1d\xc0\xbb\x26\xd7\xf5\xf7\x6a\x7b\x5c\x6a\xab\x67\x97\x78" "\x0d\xa7\x2f\xaa\x69\x3e\x23\x6f\x50\x26\xce\x0a\x5e\x4a\xab\x87\xf2" "\x99\xb6\xfb\x6c\xed\x6c\x48\xa8\x97\x86\x77\x38\x80\x4b\x8f\xd5\x74" "\x34\xee\xfd\x3b\xa3\x03\x58\x0b\x37\x5d\xc6\x8c\xbe\x0b\x03\xc2\x78" "\x87\x86\x06\xf2\xa3\x73\x0a\xfd\x89\xbf\x7c\x7b\x64\xb9\x2c\xb7\x9c" "\x00\x00\xe7\xc8\x85\xca\x36\xb4\x10\x00", 163); *(uint64_t*)0x20000188 = 0x34; *(uint64_t*)0x200001d8 = 1; *(uint64_t*)0x200001e0 = 0; *(uint64_t*)0x200001e8 = 0; *(uint32_t*)0x200001f0 = 0; syscall(__NR_sendmsg, r[0], 0x200001c0ul, 0ul); } int main(void) { syscall(__NR_mmap, 0x20000000ul, 0x1000000ul, 3ul, 0x32ul, -1, 0); do_sandbox_none(); return 0; }