| // KASAN: use-after-free Read in userfaultfd_release |
| // https://syzkaller.appspot.com/bug?id=5405c21865d6290713e1fc17ef5d148a6cd27bff |
| // status:invalid |
| // autogenerated by syzkaller (http://github.com/google/syzkaller) |
| |
| #ifndef __NR_userfaultfd |
| #define __NR_userfaultfd 323 |
| #endif |
| |
| #define _GNU_SOURCE |
| |
| #include <arpa/inet.h> |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <linux/if.h> |
| #include <linux/if_ether.h> |
| #include <linux/if_tun.h> |
| #include <linux/ip.h> |
| #include <linux/tcp.h> |
| #include <net/if_arp.h> |
| #include <pthread.h> |
| #include <sched.h> |
| #include <setjmp.h> |
| #include <signal.h> |
| #include <stdarg.h> |
| #include <stdbool.h> |
| #include <stdint.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <sys/ioctl.h> |
| #include <sys/prctl.h> |
| #include <sys/resource.h> |
| #include <sys/stat.h> |
| #include <sys/syscall.h> |
| #include <sys/time.h> |
| #include <sys/wait.h> |
| #include <unistd.h> |
| |
| const int kFailStatus = 67; |
| const int kRetryStatus = 69; |
| |
| __attribute__((noreturn)) static void doexit(int status) |
| { |
| volatile unsigned i; |
| syscall(__NR_exit_group, status); |
| for (i = 0;; i++) { |
| } |
| } |
| |
| __attribute__((noreturn)) static void fail(const char* msg, ...) |
| { |
| int e = errno; |
| fflush(stdout); |
| va_list args; |
| va_start(args, msg); |
| vfprintf(stderr, msg, args); |
| va_end(args); |
| fprintf(stderr, " (errno %d)\n", e); |
| doexit((e == ENOMEM || e == EAGAIN) ? kRetryStatus : kFailStatus); |
| } |
| |
| static __thread int skip_segv; |
| static __thread jmp_buf segv_env; |
| |
| static void segv_handler(int sig, siginfo_t* info, void* uctx) |
| { |
| uintptr_t addr = (uintptr_t)info->si_addr; |
| const uintptr_t prog_start = 1 << 20; |
| const uintptr_t prog_end = 100 << 20; |
| if (__atomic_load_n(&skip_segv, __ATOMIC_RELAXED) && |
| (addr < prog_start || addr > prog_end)) { |
| _longjmp(segv_env, 1); |
| } |
| doexit(sig); |
| for (;;) { |
| } |
| } |
| |
| static void install_segv_handler() |
| { |
| struct sigaction sa; |
| |
| memset(&sa, 0, sizeof(sa)); |
| sa.sa_handler = SIG_IGN; |
| syscall(SYS_rt_sigaction, 0x20, &sa, NULL, 8); |
| syscall(SYS_rt_sigaction, 0x21, &sa, NULL, 8); |
| |
| memset(&sa, 0, sizeof(sa)); |
| sa.sa_sigaction = segv_handler; |
| sa.sa_flags = SA_NODEFER | SA_SIGINFO; |
| sigaction(SIGSEGV, &sa, NULL); |
| sigaction(SIGBUS, &sa, NULL); |
| } |
| |
| #define NONFAILING(...) \ |
| { \ |
| __atomic_fetch_add(&skip_segv, 1, __ATOMIC_SEQ_CST); \ |
| if (_setjmp(segv_env) == 0) { \ |
| __VA_ARGS__; \ |
| } \ |
| __atomic_fetch_sub(&skip_segv, 1, __ATOMIC_SEQ_CST); \ |
| } |
| |
| static void use_temporary_dir() |
| { |
| char tmpdir_template[] = "./syzkaller.XXXXXX"; |
| char* tmpdir = mkdtemp(tmpdir_template); |
| if (!tmpdir) |
| fail("failed to mkdtemp"); |
| if (chmod(tmpdir, 0777)) |
| fail("failed to chmod"); |
| if (chdir(tmpdir)) |
| fail("failed to chdir"); |
| } |
| |
| static void vsnprintf_check(char* str, size_t size, const char* format, |
| va_list args) |
| { |
| int rv; |
| |
| rv = vsnprintf(str, size, format, args); |
| if (rv < 0) |
| fail("tun: snprintf failed"); |
| if ((size_t)rv >= size) |
| fail("tun: string '%s...' doesn't fit into buffer", str); |
| } |
| |
| static void snprintf_check(char* str, size_t size, const char* format, |
| ...) |
| { |
| va_list args; |
| |
| va_start(args, format); |
| vsnprintf_check(str, size, format, args); |
| va_end(args); |
| } |
| |
| #define COMMAND_MAX_LEN 128 |
| |
| static void execute_command(const char* format, ...) |
| { |
| va_list args; |
| char command[COMMAND_MAX_LEN]; |
| int rv; |
| |
| va_start(args, format); |
| |
| vsnprintf_check(command, sizeof(command), format, args); |
| rv = system(command); |
| if (rv != 0) |
| fail("tun: command \"%s\" failed with code %d", &command[0], rv); |
| |
| va_end(args); |
| } |
| |
| static int tunfd = -1; |
| |
| #define SYZ_TUN_MAX_PACKET_SIZE 1000 |
| |
| #define MAX_PIDS 32 |
| #define ADDR_MAX_LEN 32 |
| |
| #define LOCAL_MAC "aa:aa:aa:aa:aa:%02hx" |
| #define REMOTE_MAC "bb:bb:bb:bb:bb:%02hx" |
| |
| #define LOCAL_IPV4 "172.20.%d.170" |
| #define REMOTE_IPV4 "172.20.%d.187" |
| |
| #define LOCAL_IPV6 "fe80::%02hxaa" |
| #define REMOTE_IPV6 "fe80::%02hxbb" |
| |
| static void initialize_tun(uint64_t pid) |
| { |
| if (pid >= MAX_PIDS) |
| fail("tun: no more than %d executors", MAX_PIDS); |
| int id = pid; |
| |
| tunfd = open("/dev/net/tun", O_RDWR | O_NONBLOCK); |
| if (tunfd == -1) |
| fail("tun: can't open /dev/net/tun"); |
| |
| char iface[IFNAMSIZ]; |
| snprintf_check(iface, sizeof(iface), "syz%d", id); |
| |
| struct ifreq ifr; |
| memset(&ifr, 0, sizeof(ifr)); |
| strncpy(ifr.ifr_name, iface, IFNAMSIZ); |
| ifr.ifr_flags = IFF_TAP | IFF_NO_PI; |
| if (ioctl(tunfd, TUNSETIFF, (void*)&ifr) < 0) |
| fail("tun: ioctl(TUNSETIFF) failed"); |
| |
| char local_mac[ADDR_MAX_LEN]; |
| snprintf_check(local_mac, sizeof(local_mac), LOCAL_MAC, id); |
| char remote_mac[ADDR_MAX_LEN]; |
| snprintf_check(remote_mac, sizeof(remote_mac), REMOTE_MAC, id); |
| |
| char local_ipv4[ADDR_MAX_LEN]; |
| snprintf_check(local_ipv4, sizeof(local_ipv4), LOCAL_IPV4, id); |
| char remote_ipv4[ADDR_MAX_LEN]; |
| snprintf_check(remote_ipv4, sizeof(remote_ipv4), REMOTE_IPV4, id); |
| |
| char local_ipv6[ADDR_MAX_LEN]; |
| snprintf_check(local_ipv6, sizeof(local_ipv6), LOCAL_IPV6, id); |
| char remote_ipv6[ADDR_MAX_LEN]; |
| snprintf_check(remote_ipv6, sizeof(remote_ipv6), REMOTE_IPV6, id); |
| |
| execute_command("sysctl -w net.ipv6.conf.%s.accept_dad=0", iface); |
| |
| execute_command("sysctl -w net.ipv6.conf.%s.router_solicitations=0", |
| iface); |
| |
| execute_command("ip link set dev %s address %s", iface, local_mac); |
| execute_command("ip addr add %s/24 dev %s", local_ipv4, iface); |
| execute_command("ip -6 addr add %s/120 dev %s", local_ipv6, iface); |
| execute_command("ip neigh add %s lladdr %s dev %s nud permanent", |
| remote_ipv4, remote_mac, iface); |
| execute_command("ip -6 neigh add %s lladdr %s dev %s nud permanent", |
| remote_ipv6, remote_mac, iface); |
| execute_command("ip link set dev %s up", iface); |
| } |
| |
| static void setup_tun(uint64_t pid, bool enable_tun) |
| { |
| if (enable_tun) |
| initialize_tun(pid); |
| } |
| |
| 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 = 128 << 20; |
| setrlimit(RLIMIT_AS, &rlim); |
| rlim.rlim_cur = rlim.rlim_max = 8 << 20; |
| setrlimit(RLIMIT_MEMLOCK, &rlim); |
| rlim.rlim_cur = rlim.rlim_max = 1 << 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); |
| |
| unshare(CLONE_NEWNS); |
| unshare(CLONE_NEWIPC); |
| unshare(CLONE_IO); |
| } |
| |
| static int do_sandbox_none(int executor_pid, bool enable_tun) |
| { |
| int pid = fork(); |
| if (pid) |
| return pid; |
| |
| sandbox_common(); |
| setup_tun(executor_pid, enable_tun); |
| |
| loop(); |
| doexit(1); |
| } |
| |
| static void test(); |
| |
| void loop() |
| { |
| while (1) { |
| test(); |
| } |
| } |
| |
| long r[16]; |
| void* thr(void* arg) |
| { |
| switch ((long)arg) { |
| case 0: |
| r[0] = syscall(__NR_mmap, 0x20000000ul, 0xfff000ul, 0x3ul, 0x32ul, |
| 0xfffffffffffffffful, 0x0ul); |
| break; |
| case 1: |
| r[1] = syscall(__NR_gettid); |
| break; |
| case 2: |
| r[2] = syscall(__NR_userfaultfd, 0x0ul); |
| break; |
| case 3: |
| NONFAILING(*(uint64_t*)0x20bcf000 = (uint64_t)0xaa); |
| NONFAILING(*(uint64_t*)0x20bcf008 = (uint64_t)0x2); |
| NONFAILING(*(uint64_t*)0x20bcf010 = (uint64_t)0x0); |
| r[6] = syscall(__NR_ioctl, r[2], 0xc018aa3ful, 0x20bcf000ul); |
| break; |
| case 4: |
| NONFAILING(*(uint64_t*)0x20b54fe0 = (uint64_t)0x20e9c000); |
| NONFAILING(*(uint64_t*)0x20b54fe8 = (uint64_t)0x3000); |
| NONFAILING(*(uint64_t*)0x20b54ff0 = (uint64_t)0x1); |
| NONFAILING(*(uint64_t*)0x20b54ff8 = (uint64_t)0x0); |
| r[11] = syscall(__NR_ioctl, r[2], 0xc020aa00ul, 0x20b54fe0ul); |
| break; |
| case 5: |
| r[12] = syscall(__NR_read, r[2], 0x20517f87ul, 0x20ul); |
| break; |
| case 6: |
| NONFAILING(*(uint64_t*)0x20923000 = (uint64_t)0x5); |
| r[14] = syscall(__NR_sched_setaffinity, 0x0ul, 0x8ul, 0x20923000ul); |
| break; |
| case 7: |
| r[15] = syscall(__NR_clone, 0x0ul, 0x20000f7dul, 0x20744000ul, |
| 0x20f8b000ul, 0x20804000ul); |
| break; |
| } |
| return 0; |
| } |
| |
| void test() |
| { |
| long i; |
| pthread_t th[16]; |
| |
| memset(r, -1, sizeof(r)); |
| srand(getpid()); |
| for (i = 0; i < 8; i++) { |
| pthread_create(&th[i], 0, thr, (void*)i); |
| usleep(rand() % 10000); |
| } |
| for (i = 0; i < 8; i++) { |
| pthread_create(&th[8 + i], 0, thr, (void*)i); |
| if (rand() % 2) |
| usleep(rand() % 10000); |
| } |
| usleep(rand() % 100000); |
| } |
| |
| int main() |
| { |
| install_segv_handler(); |
| use_temporary_dir(); |
| int pid = do_sandbox_none(0, true); |
| int status = 0; |
| while (waitpid(pid, &status, __WALL) != pid) { |
| } |
| return 0; |
| } |