// https://syzkaller.appspot.com/bug?id=0ff29101efe3523c886bd8b912945241a1c6b1b4 // 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); } static void close_fds() { int fd; for (fd = 3; fd < 30; fd++) close(fd); } uint64_t r[1] = {0xffffffffffffffff}; void loop(void) { intptr_t res = 0; res = syscall(__NR_socket, 0x2000000000000021, 2, 2); if (res != -1) r[0] = res; *(uint16_t*)0x20000080 = 0x21; *(uint16_t*)0x20000082 = 0; *(uint16_t*)0x20000084 = 2; *(uint16_t*)0x20000086 = 0x10; *(uint16_t*)0x20000088 = 2; *(uint16_t*)0x2000008a = htobe16(0x4e24); *(uint8_t*)0x2000008c = 0xac; *(uint8_t*)0x2000008d = 0x14; *(uint8_t*)0x2000008e = 0x14; *(uint8_t*)0x2000008f = 0x1e; syscall(__NR_connect, r[0], 0x20000080, 0x24); *(uint64_t*)0x20005c00 = 0; *(uint32_t*)0x20005c08 = 0; *(uint64_t*)0x20005c10 = 0; *(uint64_t*)0x20005c18 = 0; *(uint64_t*)0x20005c20 = 0x20000600; memcpy((void*)0x20000600, "\x18\x00\x00\x00\x00\x00\x00\x00\x10\x01\x00\x00\x01\x00\x00\x00\x77" "\x00\x00\x00\x00\x00\x00\x00\xf4\x1b\x25\xe4\x06\xd5\x89\x37\xe7\xe8" "\x99\xe0\x52\x48\x43\xc9\x57\x7f\x89\xf7\x1e\xbd\xdf\x07\x77\x98\xb4" "\x7a\xb4\xa7\x69\x07\x47\x7a\x20\x95\x22\xad\xca\x7e\x54\x54\xb7\xde" "\xc9\xd9\xa6\x73\x05\xc0\x4a\x8c\xcf\xfc\xa5\x6c\xcb\xca\xbf\xb2\x5c" "\xc9\x46\x28\x34\x8a\x24\x59\x3c\x5d\xbd\xf2\x00\x79\x6a\x8f\xd2\x17" "\x36\x7c\x01\x7f\x76\xf1\x31\xc8\x69\x3a\xc4\x3b\x77\x47\x1b\xe9\x14" "\x70\x7d\x2c\x35\x45\xb8\x12\xf7\xf5\x8f\x43\x67\x06\xf1\x7b\x26\xae" "\x32\x08\xe5\x80\x9f\x51\x52\x8f\x24\x36\x61\x0c\x52\xb7\x24\x99\x31" "\x41\xa5\xcb\x7a\x0a\x9c\x3d\xca\x0a\x16\x78\x7a\x4d\x0c\x82\xe2\xd9" "\x82\x92\x19\xe3\xd9\x81\xd1\x96\xf1\xb7\x25\x6c\x49\xaa\xc9\x6b\x00" "\x00\x00\x00\x21\x50\xa4\x05\x8a\x8e\x43\x47\xe1\x3f\x94\xbe\x6d\x87" "\xfc\x7e\xcd\xaf\xb8\x8b\x1a\x03\xb8\xd9\xe4\xea\xc3\xf0\x07\x65\x80" "\xf6\xe7\x6a\xec\x10\x1f\xc9\x35\xe5\xc2\x5f\xac\x97\x0f\x73\xd3\xfe" "\x7d\x1f\x03\x6c\x1e\x5b\x40\x46\x42\x69\xb3\xa1\x07\x1a\x96\xf3\xd5" "\xfd\xf7\xa8\xe7\xb9\x07\xd2\x36\xe9\x1a\x85\xb6\xe2\xa1\x3b\x6b\x5e" "\xb5\x58\xd0\x81\xf5\xb2\x24\x4a\x7c\x56\x69\xb2\x24\xb8\x00\x00\x00" "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 301); *(uint64_t*)0x20005c28 = 0x18; *(uint32_t*)0x20005c30 = 0; *(uint32_t*)0x20005c38 = 0; syscall(__NR_sendmmsg, r[0], 0x20005c00, 1, 0); close_fds(); } int main(void) { syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0); do_sandbox_none(); return 0; }