// https://syzkaller.appspot.com/bug?id=191c4c580607aac67faf37e19c2af902781d9bb5 // 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 #ifndef __NR_bpf #define __NR_bpf 321 #endif static __thread int clone_ongoing; static __thread int skip_segv; static __thread jmp_buf segv_env; static void segv_handler(int sig, siginfo_t* info, void* ctx) { if (__atomic_load_n(&clone_ongoing, __ATOMIC_RELAXED) != 0) { exit(sig); } uintptr_t addr = (uintptr_t)info->si_addr; const uintptr_t prog_start = 1 << 20; const uintptr_t prog_end = 100 << 20; int skip = __atomic_load_n(&skip_segv, __ATOMIC_RELAXED) != 0; int valid = addr < prog_start || addr > prog_end; if (skip && valid) { _longjmp(segv_env, 1); } exit(sig); } static void install_segv_handler(void) { 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(...) \ ({ \ int ok = 1; \ __atomic_fetch_add(&skip_segv, 1, __ATOMIC_SEQ_CST); \ if (_setjmp(segv_env) == 0) { \ __VA_ARGS__; \ } else \ ok = 0; \ __atomic_fetch_sub(&skip_segv, 1, __ATOMIC_SEQ_CST); \ ok; \ }) static void use_temporary_dir(void) { char tmpdir_template[] = "./syzkaller.XXXXXX"; char* tmpdir = mkdtemp(tmpdir_template); if (!tmpdir) exit(1); if (chmod(tmpdir, 0777)) exit(1); if (chdir(tmpdir)) exit(1); } 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_sysctl() { char mypid[32]; snprintf(mypid, sizeof(mypid), "%d", getpid()); struct { const char* name; const char* data; } files[] = { {"/sys/kernel/debug/x86/nmi_longest_ns", "10000000000"}, {"/proc/sys/kernel/hung_task_check_interval_secs", "20"}, {"/proc/sys/net/core/bpf_jit_kallsyms", "1"}, {"/proc/sys/net/core/bpf_jit_harden", "0"}, {"/proc/sys/kernel/kptr_restrict", "0"}, {"/proc/sys/kernel/softlockup_all_cpu_backtrace", "1"}, {"/proc/sys/fs/mount-max", "100"}, {"/proc/sys/vm/oom_dump_tasks", "0"}, {"/proc/sys/debug/exception-trace", "0"}, {"/proc/sys/kernel/printk", "7 4 1 3"}, {"/proc/sys/kernel/keys/gc_delay", "1"}, {"/proc/sys/vm/oom_kill_allocating_task", "1"}, {"/proc/sys/kernel/ctrl-alt-del", "0"}, {"/proc/sys/kernel/cad_pid", mypid}, }; for (size_t i = 0; i < sizeof(files) / sizeof(files[0]); i++) { if (!write_file(files[i].name, files[i].data)) printf("write to %s failed: %s\n", files[i].name, strerror(errno)); } } uint64_t r[1] = {0xffffffffffffffff}; int main(void) { syscall(__NR_mmap, /*addr=*/0x1ffff000ul, /*len=*/0x1000ul, /*prot=*/0ul, /*flags=*/0x32ul, /*fd=*/-1, /*offset=*/0ul); syscall(__NR_mmap, /*addr=*/0x20000000ul, /*len=*/0x1000000ul, /*prot=*/7ul, /*flags=*/0x32ul, /*fd=*/-1, /*offset=*/0ul); syscall(__NR_mmap, /*addr=*/0x21000000ul, /*len=*/0x1000ul, /*prot=*/0ul, /*flags=*/0x32ul, /*fd=*/-1, /*offset=*/0ul); setup_sysctl(); install_segv_handler(); use_temporary_dir(); intptr_t res = 0; NONFAILING(*(uint32_t*)0x200000c0 = 0x11); NONFAILING(*(uint32_t*)0x200000c4 = 0xb); NONFAILING(*(uint64_t*)0x200000c8 = 0x20000180); NONFAILING(memcpy( (void*)0x20000180, "\x18\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x18\x01" "\x00\x00\x20\x20\x70\x25\x00\x00\x00\x00\x00\x20\x20\x20\x7b\x1a\xf8\xff" "\x00\x00\x00\x00\xbf\xa1\x00\x00\x00\x00\x00\x00\x07\x01\x00\x00\xf8\xff" "\xff\xff\xb7\x02\x00\x00\x08\x00\x00\x00\xb7\x03\x00\x00\x00\x00\x60\xff" "\x85\x00\x00\x00\x2d\x00\x00\x00\x95", 81)); NONFAILING(*(uint64_t*)0x200000d0 = 0x20000040); NONFAILING(memcpy((void*)0x20000040, "GPL\000", 4)); NONFAILING(*(uint32_t*)0x200000d8 = 0); NONFAILING(*(uint32_t*)0x200000dc = 0); NONFAILING(*(uint64_t*)0x200000e0 = 0); NONFAILING(*(uint32_t*)0x200000e8 = 0); NONFAILING(*(uint32_t*)0x200000ec = 0); NONFAILING(memset((void*)0x200000f0, 0, 16)); NONFAILING(*(uint32_t*)0x20000100 = 0); NONFAILING(*(uint32_t*)0x20000104 = 0); NONFAILING(*(uint32_t*)0x20000108 = 0); NONFAILING(*(uint32_t*)0x2000010c = 0); NONFAILING(*(uint64_t*)0x20000110 = 0); NONFAILING(*(uint32_t*)0x20000118 = 0); NONFAILING(*(uint32_t*)0x2000011c = 0); NONFAILING(*(uint64_t*)0x20000120 = 0); NONFAILING(*(uint32_t*)0x20000128 = 0); NONFAILING(*(uint32_t*)0x2000012c = 0); NONFAILING(*(uint32_t*)0x20000130 = 0); NONFAILING(*(uint32_t*)0x20000134 = 0); NONFAILING(*(uint64_t*)0x20000138 = 0); NONFAILING(*(uint64_t*)0x20000140 = 0); NONFAILING(*(uint32_t*)0x20000148 = 0); NONFAILING(*(uint32_t*)0x2000014c = 0); res = syscall(__NR_bpf, /*cmd=*/5ul, /*arg=*/0x200000c0ul, /*size=*/0x90ul); if (res != -1) r[0] = res; NONFAILING(*(uint64_t*)0x20000280 = 0x20000240); NONFAILING(memcpy((void*)0x20000240, "sched_switch\000", 13)); NONFAILING(*(uint32_t*)0x20000288 = r[0]); syscall(__NR_bpf, /*cmd=*/0x11ul, /*arg=*/0x20000280ul, /*size=*/0x10ul); return 0; }